Transmission method

Abstract

To provide a transmission method capable of supporting proper acquisition of communication content in response to reception of broadcast content.SOLUTION: The transmission method includes steps: transmitting broadcast content via broadcasting (S502); and transmitting acquired information via the broadcast, which is information related to the acquisition of the communication content, which is a piece of information for linking communication content transmitted by communication with the received broadcast content, and playing it back, a piece of location information indicating where the communication content is stored, a piece of information indicating whether there is communication content linked to the broadcast content, and a piece of information indicating the type of communication content (S501). The acquired information includes a piece of information indicating the expiration date of the communication content.SELECTED DRAWING: Figure 26

Description

[Technical Field]

[0001] The present invention relates to a receiving method for synchronously playing back content such as video, audio, and subtitles obtained through broadcasting and communication, respectively. [Background technology]

[0002] In recent years, various services that combine broadcasting and communications have been proposed.

[0003] As a device for receiving such services, for example, the following receiving device has been proposed (see, for example, Patent Documents 1, 2 and 3).

[0004] The receiving device receives broadcast content from a digital broadcast signal, receives communication content linked to the broadcast content from a communication network, and presents the broadcast content and communication content in synchronization with each other. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-9332 [Patent Document 2] Japanese Patent Application Laid-Open No. 2013-9359 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-9341 Summary of the Invention [Problem to be solved by the invention]

[0006] Broadcast content is usually transmitted from a broadcast station at a predetermined time. Therefore, when the broadcast content and the communication content are presented (played) in synchronization with each other, the receiving device acquires and plays the communication content in response to reception of the broadcast content.

[0007] However, there are limitations on the reception device's acquisition of communication content, such as the capacity of the buffer for communication content, etc. Therefore, there is room for further study on the method of reception device's acquisition of communication content.

[0008] The present invention provides a transmission method that assists in properly acquiring communication content in response to receiving broadcast content. [Means for solving the problem]

[0009] A transmission method according to one aspect of the present invention transmits broadcast content via broadcasting, and transmits information for playing communication content transmitted via communication in conjunction with the received broadcast content, the information including acquisition information related to the acquisition of the communication content, location information indicating the storage location of the communication content, information indicating whether there is communication content that is linked to the broadcast content, and information indicating the type of the communication content, via the broadcasting, and the acquisition information includes information indicating the expiration date of the communication content.

[0010] These comprehensive or specific aspects may be realized as a system, an apparatus, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, etc. Furthermore, these comprehensive or specific aspects may be realized as any combination of a system, an apparatus, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0011] According to a transmission method according to an aspect of the present invention, it is possible to assist in appropriately acquiring communication content in response to reception of broadcast content. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram showing a configuration of a receiving device 1 according to a first embodiment of the present invention. [Figure 2]FIG. 2 is a block diagram showing an example of the configuration of the buffer 13 and the buffer 22 shown in FIG. [Figure 3] FIG. 3 is a diagram showing an example of state transition of content presentation in the receiving device 1 of FIG. [Figure 4] FIG. 4 is a diagram showing a signal image for explaining an example of a method for synchronously presenting broadcast content and communication content in the receiving device 1 of FIG. [Figure 5] FIG. 5 is a flowchart showing an example of the processing operation of the method for synchronously presenting broadcast content and communication content by the receiving device 1 of FIG. [Figure 6] FIG. 6 is a diagram showing a signal image for explaining another example of the synchronous presentation method. [Figure 7] FIG. 7 is a diagram showing a signal image for explaining yet another example of a synchronous presentation method. [Figure 8] FIG. 8 is a flowchart showing another example of the processing operation of the synchronous presentation method. [Figure 9] FIG. 9 is a block diagram showing a configuration of a receiving device 1A according to a modification of the first embodiment. [Figure 10] FIG. 10 is a block diagram showing a configuration of a receiving device 1B according to another variation of the first embodiment. [Figure 11] FIG. 11 is a diagram showing an example of the setting menu screen. [Figure 12] FIG. 12 is a diagram showing an example of the synchronous presentation method setting screen. [Figure 13] FIG. 13 is a diagram showing an example of the synchronous presentation manual setting screen. [Figure 14] FIG. 14 is a block diagram showing a configuration of a receiving device 100 according to the second embodiment of the present invention. [Figure 15] FIG. 15 is a block diagram showing an example of the configuration of the control management unit 141 in FIG. [Figure 16] FIG. 16 is a flowchart showing an example of the initial operation of the delay buffer and de-jitter buffer after receiving apparatus 100 of FIG. 14 starts receiving broadcast communication. [Figure 17]FIG. 17 is a flowchart showing an example of the control method determination operation by the control method determination unit 174 of FIG. [Figure 18] FIG. 18 is a block diagram showing a configuration of a receiving device 100A according to a modification of the second embodiment. [Figure 19] FIG. 19 is a flowchart showing an example of an operation of the receiving device according to the third embodiment to acquire communication content. [Figure 20] FIG. 20 is a flowchart showing an example of a synchronized playback operation including acquisition of a communication content. [Figure 21] FIG. 21 is a flowchart showing an example of an operation in which a broadcasting and communication cooperative service is started in the middle of a program. [Figure 22] FIG. 22 is a flowchart showing an example of a filing operation of communication content. [Figure 23] FIG. 23 is a flowchart showing an example of determining whether or not the online content can be acquired at any time. [Figure 24] FIG. 24 is a flowchart showing an example of the operation when delayed presentation of broadcast content is not permitted. [Figure 25] FIG. 25 is a block diagram showing the configuration of a transmitting device. [Figure 26] FIG. 26 is a flowchart showing an example of the operation of the transmitting device. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Findings that formed the basis of the invention 1) The receiving device described in Patent Document 1 receives broadcast content from a digital broadcast signal and receives communication content linked to the broadcast content from a communication network. The receiving device then temporarily stores the received broadcast content in a first synchronization buffer and temporarily stores the received communication content in a second synchronization buffer. The receiving device controls the output time of content output from either the first synchronization buffer or the second synchronization buffer according to a time specified by an instruction execution unit, and delays the presentation of either the broadcast content or the communication content. This makes it possible to present the broadcast content and the communication content, which are received at different times, in a synchronized manner.

[0014] Furthermore, the receiving device described in Patent Document 2 synchronizes the presentation of broadcast content and online content by delaying the presentation of the broadcast content. In this receiving device, the online content is acquired in response to an external operation or an external control signal, and after the acquisition of the online content is completed, delayed presentation is initiated, which presents the broadcast content at a later time than when the broadcast content is normally presented. This makes it possible to present the broadcast content normally even while the online content is being acquired.

[0015] In the conventional receiving devices described in Patent Documents 1 and 2, when switching from a state in which broadcast content is being played but not network content to a state in which both broadcast content and network content are being played, it is necessary to delay the presentation of the broadcast content in accordance with the delay time between the reception time of the network content and the reception time of the broadcast content. As a result, the broadcast content presented to the viewer is temporarily interrupted. This has a greater impact on the viewer the greater the delay time between the reception time of the network content and the reception time of the broadcast content.

[0016] The same problem occurs when the reception time of the broadcast content is delayed relative to the reception time of the communication content. That is, when switching from a state in which the communication content is being played but the broadcast content is not being played to a state in which both the communication content and the broadcast content are being played, the presentation of the communication content must be delayed according to the delay time between the reception time of the broadcast content and the reception time of the communication content. As a result, the communication content presented to the viewer is temporarily interrupted. The greater the delay time between the reception time of the broadcast content and the reception time of the communication content, the greater the impact on the viewer.

[0017] However, so far no technical solution to this problem has been explored.

[0018] Therefore, the inventors have investigated technical solutions to this problem.

[0019] As a result of this study, the inventors discovered that the impact on viewers can be reduced by, for example, notifying viewers about the synchronization between broadcast and communication before and after delaying the presentation of broadcast content or before and after delaying the presentation of communication content.

[0020] Hereinafter, an embodiment based on a solution obtained based on this knowledge will be described.

[0021] (Embodiment 1) FIG. 1 is a block diagram showing a configuration of a receiving device 1 which is a broadcast and communication cooperative receiving device according to the first embodiment of the present invention.

[0022] The receiving device 1 includes a digital broadcast receiving unit 11, a separation unit 12, a buffer 13, a decoding unit 14, a communication transmitting / receiving unit 21, a buffer 22, a decoding unit 23, a content generating unit 31, a communication transmitting / receiving unit 41, an operation input unit 42, and a control unit 51.

[0023] However, the receiving device 1 is, for example, a device such as a television receiver, a portable television, a recorder, a set-top box, a smartphone, or a tablet.

[0024] Digital broadcast receiving unit 11 receives as input a digital broadcast signal received by an external broadcast antenna 3. Digital broadcast receiving unit 11 then selects a desired channel from the digital broadcast signal, performs demodulation processing, error correction processing, etc. on the digital broadcast signal of the selected desired channel, generates a transport stream, and outputs it to separation unit 12. Note that receiving device 1 may also be equipped with broadcast antenna 3 internally.

[0025] However, digital broadcasting includes, for example, terrestrial digital broadcasting, BS (Broadcasting Satellite) digital broadcasting, CS (Communications Satellite) digital broadcasting, cable television, optical fiber, and other IP (Internet Protocol) broadcasting. Examples include broadcasting using the IEEE 802.11n Protocol (IEEE 802.11n) network.

[0026] The demultiplexer 12 demultiplexes the transport stream generated by the digital broadcast receiver 11 into video data, audio data, data broadcast, etc. The demultiplexer 12 also acquires various types of control information included in the transport stream.

[0027] The control information included in the transport stream includes, for example, system information such as PSI (Program Specific Information) and SI (Service Information), and synchronization information such as PCR (Program Clock Synchronization Information). The application information table (AIT) contains information about the application. The AIT contains, for example, an application ID that identifies the application, a control code that can control the life cycle of the application, such as starting and ending, and location information of the application.

[0028] The video data, audio data, etc. output from the separator 12 are configured as PES (Packetized Elementary Stream) packets. The PES header included in each PES packet stores a PTS (Presentation Time Stamp) and a DTS (Decoding Time Stamp) as presentation time information for synchronization. Note that the PES header may not include either the PTS or the DTS, or both.

[0029] The separated video data, audio data, etc. are output from the separator 12 to the buffer 13, and the PCR, AIT, etc. are output from the separator 12 to the control unit 51.

[0030] The buffer 13 stores the video data, audio data, etc. output from the separation unit 12. The buffer 13 outputs content data for each component, such as video and audio, in PES packet units to one or both of the decoding unit 14 and the communication transmission / reception unit 41 at a timing instructed by the control unit 51. The buffer 13 will be described further below with reference to FIG. 2.

[0031] The decoding unit 14 converts the PES packets for each component, such as video and audio, output from the buffer 13 into an elementary stream (ES), and extracts the PTS and DTS from the PES header of the PES packet. The decoding unit 14 also outputs the extracted PTS and DTS to the control unit 51. The decoding unit 14 then decodes the elementary stream for each component and outputs it to the content generation unit 31. However, if the order of picture frames of the video content before decoding differs from the order of picture frames after decoding, the decoding unit 14 rearranges the order using an internal buffer before outputting it to the content generation unit 31.

[0032] The communication transmitting / receiving unit 21 acquires applications and AV content from a content server provided by a company related to the broadcasting company or another company via a communication network. The communication transmitting / receiving unit 21 may also acquire control information such as AIT via the communication network. AV content provided by a communication company includes file data, video data, audio data, etc. The communication transmitting / receiving unit 21 outputs the acquired applications and control information to the control unit 51. The communication transmitting / receiving unit 21 outputs the acquired AV content to the buffer 22.

[0033] The communication transmitting / receiving unit 21 and a communication transmitting / receiving unit 41 (to be described later) are connected to, for example, a wireless LAN (Local Area Network). Communication is performed using a communication method that complies with communication standards such as IEEE 1394, ...

[0034] The buffer 22 stores content data of AV content output from the communication transmitting / receiving unit 21. The buffer 22 outputs content data for each component, such as video and audio, in PES packet units to one or both of the decoding unit 23 and the communication transmitting / receiving unit 41 at a timing instructed by the control unit 51. The buffer 22 will be described further below with reference to FIG. 2.

[0035] The decoding unit 23 converts the PES packets for each component, such as video and audio, output from the buffer 22 into an elementary stream (ES), and extracts the PTS and DTS from the PES header of the PES packet. The decoding unit 23 also outputs the extracted PTS and DTS to the control unit 51. The decoding unit 23 then decodes the elementary stream for each component and outputs it to the content generation unit 31. However, if the order of picture frames of the video content before decoding differs from the order of picture frames after decoding, the decoding unit 23 rearranges the order using an internal buffer before outputting it to the content generation unit 31.

[0036] The content generation unit 31 uses the content data of each component (video, audio, subtitles, etc.) output from the decoding unit 14 and the content data of each component (video, audio, subtitles, etc.) output from the decoding unit 23 to generate presentation content for the service in accordance with instructions from the control unit 51. The presentation content generated by the content generation unit 31 is output to the external presentation unit 5 and presented by the presentation unit 5. Note that the receiving device 1 may also be provided with the presentation unit 5 internally.

[0037] The communication transmitting / receiving unit 41 communicates with a content presentation device other than the presentation unit 5 and an input interface operated by a viewer. Examples of content presentation devices include television receivers, portable televisions, smartphones, and tablets. The communication transmitting / receiving unit 41 transmits PES packets output from the buffers 13 and 22 to the content presentation device. The communication transmitting / receiving unit 41 also transmits data received from the control unit 51 to the content presentation device. Examples of input interfaces include a remote control, a tablet terminal, a smartphone, a keyboard, a mouse, a camera, and a microphone of a personal computer. The communication transmitting / receiving unit 41 also outputs input content received from the input interface to the operation input unit 42 or the control unit 51. The content presentation device and the input interface may be the same device or different devices.

[0038] The operation input unit 42 acquires a control signal from an external input interface or a built-in input interface in response to an operation by a viewer using the input interface, and transmits control information corresponding to the acquired control signal to the control unit 51. Examples of the input interface include a remote control, a tablet terminal, a smartphone, a keyboard of a personal computer, a mouse, a camera, and a microphone. The operation by the viewer using the input interface includes, for example, pressing a button physically or virtually arranged on the screen, a gesture, a voice operation, or a combination thereof. The control signal from the input interface may be input to the operation input unit 42 via the communication transceiver 41, or may be input directly to the control unit 51 via the communication transceiver 41. When the control signal from the input interface is input directly to the control unit 51 via the communication transceiver 41, the receiving device 1 does not need to include the operation input unit 42.

[0039] The control unit 51 generates a reference clock signal using the PCR output from the separation unit 12. This generated reference clock signal is used to control the output timing of the buffers 13 and 22, and the like.

[0040] The control unit 51 uses the PTS output from the decoding unit 14 to generate control information for adjusting the output timing of each piece of content (video content, audio content, etc.) transmitted by broadcasting, and outputs the control information to a PES buffer 71 (described later) in the buffer 13. The control unit 51 also uses the PTS output from the decoding unit 23 to generate control information for adjusting the output timing of each piece of content (video content, audio content, etc.) transmitted by communication, and outputs the control information to a PES buffer 71 (described later) in the buffer 22.

[0041] Furthermore, the control unit 51 calculates the delay time between the broadcast content and the communication content using the PTS output from the decoding unit 14 and the PTS output from the decoding unit 23. Then, based on the calculated delay time, it generates control information for matching the output timing of the broadcast content and the communication content, and outputs the control information to a synchronization buffer 72 (described later) in the buffer 13 and a synchronization buffer 72 (described later) in the buffer 22. The control unit 51 also instructs the content generation unit 31 to notify the viewer about the synchronization between the broadcast content and the communication content (synchronization presentation notification).

[0042] The synchronous presentation notification is, for example, a notification to the viewer of the occurrence of discontinuous video presentation when broadcast content switches from normal presentation (described later) to delayed presentation (described later), or a notification to the viewer of the occurrence of overlapping video presentation. This synchronous presentation notification will be described later, including specific examples.

[0043] An example of the configuration of the buffer 13 and the buffer 22 will be described below with reference to Fig. 2. The buffer 13 and the buffer 22 can have the same configuration, so they will be described together.

[0044] FIG. 2 is a block diagram showing an example of the configuration of the buffer 13 and the buffer 22 shown in FIG.

[0045] The buffers 13 and 22 each include a PES buffer 71 and a synchronization buffer 72 .

[0046] The PES buffer 71 is a buffer for aligning the output timing of content such as video content, audio content, etc. The PES buffer 71 converts each content such as video content, audio content, etc. into PES packets, and outputs content data in PES units at the output timing instructed by the control unit 51 using control information.

[0047] The synchronization buffer 72 is a buffer for aligning the output timing between the broadcast content and the communication content, and outputs content data in PES units at the timing instructed by the control unit 51 using control information.

[0048] However, the PES buffer 71 and synchronization buffer 72 can output content data in PES units with any delay time and any output timing, and the delay time and output timing are all in accordance with instructions from the control unit 51.

[0049] A synchronous presentation method for presenting broadcast content and communication content by synchronizing the output timing of the broadcast content and communication content will be described below.

[0050] There are two types of broadcasting and communication collaboration services: one that controls the collaboration between broadcasting and communication using an application such as HTML5, and one that controls the collaboration between broadcasting and communication without the intervention of an application. Note that the following describes an example in which a broadcasting and communication collaboration service is provided using an application, but the application may be an HTML5 application or a resident application on the receiver. Also, some of the functions of the resident application or receiver may be provided as an API and controlled by another application such as HTML5.

[0051] Broadcasting and communication integrated services include dependent services in which applications are linked to AV content, and independent services in which applications are not linked to AV content. There are also various types of communication content.

[0052] In the following explanation, we consider a use case in which a dependent service linked to broadcast content presents communication content linked to the broadcast content. Also, we assume that the communication content is a real-time multicast distribution of live video, for which packets cannot be acquired in advance.

[0053] FIG. 3 shows an example of state transition of content presentation in the receiving device 1, which will be used to explain a specific example of a method for synchronously presenting broadcast content and communication content.

[0054] In the state transition diagram of Figure 3, the receiving device 1 starts from a power-off state (broadcast-off / communication-off state). Then, by turning on broadcast content presentation, the receiving device 1 transitions from the broadcast-off / communication-off state to a state in which only broadcast content is presented (broadcast-on / communication-off state). Furthermore, by turning on communication content presentation, the receiving device 1 transitions from the broadcast-on / communication-off state to a state in which both broadcast content and communication content are presented (broadcast-on / communication-on state).

[0055] In the following, the "broadcast ON / communication OFF state" is defined as "State A," and the "broadcast ON / communication ON state" is defined as "State B." In addition, the period from when it is decided to transition from "State A" to "State B" until the transition is completed is defined as the "transition period."

[0056] In order to provide a broadcasting and communication integrated service, it is a prerequisite that the application is running. Therefore, if the application is not running when providing the broadcasting and communication integrated service, it must be started. Furthermore, in order to provide only the broadcasting service, the application does not necessarily have to be running.

[0057] For example, when transitioning from state A to state B, if an application is not running in state A, it is necessary to start the application. At this time, the application is started based on the AIT included in the broadcast signal.

[0058] The timing of application startup may be explicitly specified by the viewer based on the AIT stored in the broadcast content or communication content, or may be automatically started dynamically in conjunction with the content based on the application startup information in the AIT, etc. The timing of application termination may be explicitly specified by the viewer based on the AIT stored in the broadcast content or communication content, or may be automatically terminated dynamically in conjunction with the content based on the application termination information in the AIT, etc.

[0059] Methods for turning on communication content while broadcast content is being presented include a method in which the viewer explicitly specifies it based on the AIT stored in the broadcast content, and a method in which communication content is automatically started based on the AIT stored in the broadcast content.

[0060] Generally, the reception of communication content involves a larger delay than the reception of broadcast content, so when live video is transmitted by broadcast and communication, the communication content is received at the receiving end with a delay relative to the broadcast content.

[0061] In order to start presenting communication content while broadcast content is being presented and present the broadcast content and communication content in synchronization, it is necessary to present the broadcast content with a delay.

[0062] An example of a method for synchronously presenting broadcast content and communication content in the state transition of content presentation shown in FIG. 3 will be described with reference to FIGS. 4 and 5. FIG.

[0063] FIG. 4 is a diagram showing a signal image for explaining an example of a method for synchronously presenting broadcast content and communication content in the state transition of content presentation shown in FIG.

[0064] Figure 4(a) shows the time signal of broadcast content without delay. Broadcast presentation using this signal is defined as "normal presentation."

[0065] Figure 4(b) shows the time signal of delayed broadcast content. Broadcast presentation using this signal is defined as "delayed presentation." Note that "D" in the figure is the delay time between the reception time of the communication content and the reception time of the broadcast content.

[0066] FIG. 4(c) shows the time signal of the communication content.

[0067] FIG. 4(d) shows the time signal of the broadcast content that is actually presented.

[0068] FIG. 4(e) shows the time signal of the communication content that is actually presented.

[0069] The receiving device 1 normally presents the broadcast content until time T1, and from time T1 when acquisition of the communication content begins until time T2 when preparation for presentation of the communication content is complete, that is, until the transition from state A to state B is complete.

[0070] Then, during the period after time T2 when preparation for presenting the communication content is complete, that is, after the transition from state A to state B is complete, the receiving device 1 presents the communication content together with the broadcast content with a delay.

[0071] In this way, when the transition from State A to State B is complete, the presentation of the broadcast content switches from normal presentation to delayed presentation. Therefore, when the transition from State A to State B is complete, the broadcast content presentation becomes discontinuous video, etc. Also, for a while after the delayed presentation begins, the broadcast content presentation becomes overlapping video, etc. that was presented once in normal presentation. The discontinuous presentation of video, etc. or overlapping video, etc. can cause viewers to feel uneasy and sometimes uncomfortable.

[0072] Therefore, during the overlapping presentation period of the broadcast content, the receiving device 1 notifies the viewer of the synchronization between the broadcast content and the communication content (synchronization presentation notification) (for example, by presenting a message on the presentation unit 5 stating that "broadcast content is being overlappingly presented to synchronize the broadcast content and the communication content").

[0073] By providing such synchronous presentation notification, the viewer can understand the reason for the discontinuous presentation of images, etc. or the overlapping presentation of images, etc., thereby alleviating the sense of discomfort or annoyance that the viewer may experience while watching.

[0074] Fig. 5 is a flowchart showing an example of the processing operation of the method for synchronously presenting broadcast content and communication content by the receiving device 1 in the state transition of content presentation shown in Fig. 3. However, at the start of the flowchart in Fig. 5, the receiving device 1 is in a power-off state (broadcast-off / communication-off state).

[0075] By turning on the broadcast content presentation, the receiving device 1 transitions from a power-off state (broadcast-off / communication-off state) to a broadcast-on / communication-off state (state A) (step S11). The receiving device 1 starts acquiring the broadcast content and starts normal presentation of the broadcast content (step S12).

[0076] Next, the receiving device 1 starts acquiring communication content upon acquiring the application (step S13).

[0077] The receiving device 1 determines whether or not preparation for presenting the online content has been completed (step S14). The processing of step S14 is performed until it is determined that preparation for presenting the online content has been completed (S14: No). Then, if it is determined that preparation for presenting the online content has been completed (S14: Yes), the processing of step S15 is performed. Note that the determination of whether or not preparation for acquiring the online content has been completed is made, for example, when a predetermined amount of content data of the online content has been accumulated in the buffer 22.

[0078] The control unit 51 of the receiving device 1 compares the PTS of the decoded broadcast content with the PTS of the communication content, and calculates the delay time of the communication content relative to the broadcast content (step S15).

[0079] The control unit 51 generates control information for synchronizing the output timing of the broadcast content and the communication content based on the delay time calculated in step S15, and outputs the control information to the synchronization buffer 72 in the buffer 13 and the synchronization buffer 72 in the buffer 22. The synchronization buffer 72 in the buffer 13 delays the buffer output based on the delay time calculated in step S15 in accordance with the control information, and the synchronization buffer 72 in the buffer 22 performs buffer output in accordance with the control information. As a result, the receiving device 1 switches the presentation of the broadcast content from normal presentation to delayed presentation and starts the delayed presentation, and simultaneously starts presenting the communication content. Furthermore, the control unit 51 instructs the content generation unit 31 to present a message for synchronization presentation notification (for example, a message stating, "Broadcast content is being presented overlappingly to synchronize the broadcast content and the communication content"), and the content generation unit 31 starts presenting the message for synchronization presentation to the presentation unit 5 based on this instruction (step S16).

[0080] The control unit 51 determines whether the overlapping presentation of the broadcast content has ended based on the delay time calculated in step S15 (step S17). The process of step S17 is repeated until it is determined that the overlapping presentation of the broadcast content has ended (S17: No). If it is determined that the overlapping presentation of the broadcast content has ended (S17: Yes), the control unit 51 instructs the content generation unit 31 to end the presentation of the synchronous presentation notification message, and the content generation unit 31 ends the presentation of the synchronous notification message to the presentation unit 5 based on this instruction (step S18).

[0081] (Supplementary note to the first embodiment) The following provides supplementary information on the first embodiment.

[0082] (1) The method of synchronously presenting broadcast content and communication content described in the first embodiment is an example, and the present invention is not limited to this.

[0083] For example, the synchronous presentation method shown in Fig. 6 may be used, but the time signals in Fig. 6(a) to (e) are of the same type as the time signals in Fig. 4(a) to (e), respectively.

[0084] In the synchronous presentation method of FIG. 4, broadcast content is normally presented during a state transition period, that is, during the period from when acquisition of the communication content begins until preparation for presentation of the communication content is complete.

[0085] 6, in contrast, during the state transition period, that is, the period from when acquisition of the communication content starts until preparation for presentation of the communication content is completed, the presentation of the broadcast content is interrupted and the screen of the presentation unit 5 is blacked out. At the same time, the receiving device 1 presents, on the presentation unit 5, a message indicating that it is waiting to synchronize the broadcast content with the communication content, for example, to notify the viewer of the synchronous presentation.

[0086] Furthermore, various synchronous presentation methods are possible by changing the method of controlling the buffer clock timing or the presentation timing, such as the synchronous presentation method shown in Figure 7. However, the time signals in Figures 7(a) to 7(e) are the same type as the time signals in Figures 4(a) to 4(e), respectively.

[0087] In the synchronous presentation method of FIG. 7, the receiving device 1 starts slow playback of the broadcast content upon acquiring the communication content, and transitions to a state in which delayed presentation of the broadcast content and presentation of the communication content are performed while comparing the completion of preparation for presentation of the communication content with the playback time of the broadcast content. At the same time, the receiving device 1 displays a message on the presentation unit 5 indicating that slow playback of the broadcast content is being performed to synchronize the broadcast content and the communication content, for example, to notify the viewer of the synchronous presentation. Note that slow playback can be achieved by extending the time interval between buffer outputs. The broadcast content is gradually delayed by slow playback, and when the delay adjustment is completed and the presentation time of the broadcast content and the presentation time of the communication content coincide, the broadcast content and the communication content are presented in a synchronized manner. In this case, the time when preparation for presentation of the communication content is completed does not coincide with the timing of synchronous presentation.

[0088] The playback timing and clock control are controlled by the control unit 51. The control unit 51 also outputs appropriate presentation and presentation timing to the content generation unit 31 in accordance with the synchronous presentation method.

[0089] The synchronized presentation method of FIG. 7 allows smoother presentation of broadcast content and communication content when they are presented in synchronization with each other.

[0090] (2) In the synchronous presentation method of the first embodiment, the presentation of the broadcast content is switched from normal presentation to delayed presentation when the preparation of the communication content is completed. However, this is not limited to this, and for example, the broadcast content may be delayed in advance. An example of this will be described using the flowchart of Fig. 8. However, at the start of the flowchart of Fig. 8, the receiving device 1 is in a power-off state (broadcast-off / communication-off state).

[0091] By turning on the broadcast content presentation, the receiving device 1 transitions from a power-off state (broadcast-off / communication-off state) to a broadcast-on / communication-off state (step S51). The receiving device 1 starts acquiring the broadcast content and starts normal presentation of the broadcast content (step S52).

[0092] During normal presentation of the broadcast content, the receiving device 1 starts an application (hereinafter referred to as a "delayed presentation application") that presents the broadcast content in a delayed manner as a first application (step S53). Examples of the delayed presentation timing of the broadcast include timing designated by a viewer, timing designated by a broadcaster or other business in the AIT of communication or broadcast, or timing designated by an application acquired based on the AIT.

[0093] After starting the delayed presentation application, the receiving device 1 acquires the communication content in the control unit 51, compares the PTS of the decoded broadcast content with the PTS of the communication content, and calculates the delay time of the communication content relative to the broadcast content (step S54).

[0094] The control unit 51 controls the output delay of the synchronization buffer 72 in the buffer 13 based on the delay time calculated in step S54, and as a result, the receiving device 1 switches the presentation of the broadcast content from normal presentation to delayed presentation and starts the delayed presentation. Furthermore, the control unit 51 instructs the content generation unit 31 to present a message for synchronous presentation notification (for example, a message to the effect that "broadcast content is being presented overlappingly to synchronize the broadcast content with the communication content"), and the content generation unit 31 starts presenting the message for synchronous presentation notification to the presentation unit 5 based on this instruction (step S55).

[0095] The control unit 51 determines whether the overlapping presentation of the broadcast content has ended based on the delay time calculated in step S54 (step S56). The process of step S56 is repeated until it is determined that the overlapping presentation of the broadcast content has ended (S56: No). If it is determined that the overlapping presentation of the broadcast content has ended (S56: Yes), the control unit 51 instructs the content generation unit 31 to end the presentation of the message for synchronous presentation notification, and the content generation unit 31 ends the presentation of the message for synchronous presentation notification to the presentation unit 5 based on this instruction (step S57).

[0096] In the broadcast ON / communication OFF state and during delayed presentation of the broadcast content, the receiving device 1 starts up the second application, thereby starting to acquire the communication content (step S58).

[0097] The receiving device 1 determines whether or not preparation for presenting the online content is complete (step S59). The process of step S59 is repeated until it is determined that preparation for presenting the online content is complete (S59: No). If it is determined that preparation for presenting the online content is complete (S59: Yes), the receiving device 1 starts presenting the online content (step S60).

[0098] In the case of a program that may require delayed presentation, the broadcast content is presented in advance with a delay at a timing that will cause minimal discomfort to the viewer, such as when broadcast reception starts, when selecting a channel, or during a commercial, thereby enabling smooth synchronized presentation of the broadcast content and the communication content.

[0099] Note that, for example, depending on the timing at which delayed presentation of broadcast content is disclosed (for example, when broadcast reception starts or when a channel is selected), the message for synchronous presentation notification may not be presented.

[0100] (3) The content and period of the notification (synchronous presentation notification) regarding the synchronous presentation of broadcast content and communication content to viewers in the synchronous presentation method described in embodiment 1 are merely examples and are not limited to these.

[0101] The synchronous presentation notification will be described below, including the contents described in the first embodiment.

[0102] The content of the synchronous presentation notification may include, for example, the presentation of a message relating to the synchronous presentation of broadcast content and communication content, and the presentation of animation of discontinuous video.

[0103] Specifically, for example, it is presented as follows: -Display a message or icon that indicates to the viewer the synchronous presentation method that has been set. - Discontinuous video display occurs, or the discontinuous video display occurs. A message or icon is displayed to the listener. -Display a message or icon to inform the viewer that the video is being presented twice. -Insert animation between images to eliminate discontinuity.

[0104] In addition to the display of messages or icons, there are also other methods such as displaying captions and outputting audio. Also, the information may be presented using an external device.

[0105] The timing or period of the synchronous presentation notification may be, for example, a period during which overlapping presentation of broadcast content is being performed, a period from when acquisition of communication content begins until the overlapping presentation of broadcast content ends, a timing or period corresponding to an event of the receiving device 1, such as when an application is started, or when preparation of communication content is completed. It may also be a timing or period based on an interface operation by a viewer. The synchronous presentation notification may be performed only while the viewer permits the synchronous presentation notification.

[0106] The control unit 51 determines the content, timing, or period of the synchronous presentation notification according to, for example, a synchronous presentation method specified in an application, a predetermined rule, or settings of the receiving device, and instructs the content generation unit 31. The content generation unit 31 executes the synchronous presentation notification of the determined content at the determined timing or period according to the instruction of the control unit 51. Note that the viewer may or may not be able to configure the settings of the receiving device.

[0107] In addition, it may be possible to embed a control signal in broadcasting or communication that indicates the content, timing, or duration of the synchronized presentation notification, so that the broadcasting company, a company related to the broadcasting company, or another company can indicate the content, timing, or duration of the synchronized presentation notification depending on the content.

[0108] (4) In the first embodiment, the timing of acquiring the communication content is the same as the timing of acquiring the application, but this is not limited to this and may be different timing. Note that the timing of acquiring the communication content follows, for example, instructions from the application.

[0109] (5) In the first embodiment, the state transition of the receiving device 1 is described as being the state transition shown in FIG. 3, but is not limited to this and may be, for example, as follows.

[0110] The receiving device 1 is also required to delay the broadcast content during normal presentation of the broadcast content and during a state transition from a state in which an independent communication application not linked to the content is running (broadcast ON / communication independent application ON / linked application OFF state) to a state in which an application linked to the broadcast is running (broadcast ON / communication independent application ON / linked application ON state). Even in this case, it is possible to apply substantially the same content as the synchronous presentation method and synchronous presentation notification in the synchronous presentation method described in the first embodiment and the supplement to the first embodiment.

[0111] (6) In the first embodiment and supplementary paragraph (2) of the first embodiment, the PTS output after decoding is used to calculate the delay time between the broadcast content and the communication content. However, this is not limited to this, and the calculation may be performed using the DTS, or using two pieces of information, the PTS and the DTS. The calculation may also be performed using the PTS and the DTS before decoding. The calculation may also be performed using the PCR, or a clock (STC) generated based on the PCR, the PTS, and the DTS. If the reference clock is NTP, the calculation may be performed using NTP. If the broadcast content and the communication content use different reference clocks, the calculation may also be performed using timeline auxiliary information indicating the correspondence between the respective reference clocks.

[0112] The buffer control timing is calculated taking into consideration the location where the PTS and DTS are calculated and the buffer position. As an example where the location where the PTS and DTS are calculated and the buffer position are different, the following configuration can be used.

[0113] In the first embodiment, the PTS and DTS are extracted by the decoder 14. However, the conversion from PES packets to ESs and the extraction of PTS and DTSs may be performed in the PES buffer 71 in the buffer 13, rather than in the decoder 14. In this case, it is desirable that the positions of the PES buffer 71 and the synchronization buffer 72 in the buffer 13 are reversed. The PES buffer 71 outputs the extracted PTS and DTS to the control unit 51. The PES buffer 71 outputs content data for each component, such as video and audio, to one or both of the decoder 14 and the communication transceiver 41 at a timing instructed by the control unit 51. Similarly, the conversion from PES packets to ESs and the extraction of PTS and DTSs may be performed in the PES buffer 71 in the buffer 22, rather than in the decoder 23. In this case, it is desirable that the positions of the PES buffer 71 and the synchronization buffer 72 in the buffer 22 are reversed. The PES buffer 71 outputs the extracted PTS and DTS to the control unit 51. The PES buffer 71 outputs content data for each component, such as video and audio, to one or both of the decoding unit 23 and the communication transmitting / receiving unit 41 at the timing instructed by the control unit 51. Note that the above configuration is equivalent to the configuration described in the second embodiment, which will be described later, and the PES buffer 71 in Fig. 2 corresponds to the separation buffer 114 in Figs. 14 and 18.

[0114] (7) In the first embodiment, it has been explained that content data for each component, such as video and audio, is output to the communication transceiver 41 in PES packet units at the timing instructed by the control unit 51, and the communication transceiver 41 transmits the content data and data received from the control unit 51 to the content presentation device. More specifically, the communication transceiver 41 re-multiplexes the access units and PES packets for each component, such as video and audio, and the control information and clock information input from the control unit 51 using a specific multiplexing method, and then transmits them to the linked terminal. Examples of multiplexing methods include MP4, MPEG2-TS, MPEG-DASH, and MMT.

[0115] (8) In the first embodiment, the communication content is delayed by a certain time from the broadcast content. However, it is also possible that the broadcast content is delayed from the communication content. In this case, the broadcast content is presented in one pattern, namely, normal presentation, and the communication content is presented in two patterns, namely, normal presentation and delayed presentation. Except for this point, it is possible to apply substantially the same content as the synchronous presentation method and the synchronous presentation notification in the synchronous presentation method described in the first embodiment and the supplement to the first embodiment.

[0116] In embodiment 1, it was assumed that the communication content is delayed by a fixed time relative to the broadcast content, but if the delay time of the communication content relative to the broadcast content is not fixed, for example, due to the influence of transmission jitter in the communication transmission path, the buffer is appropriately controlled to present the broadcast content and the communication content in synchronization.

[0117] (9) In the first embodiment, the transition from the broadcast ON / communication OFF state to the broadcast ON / communication ON state has been described, but there is also a transition from the broadcast ON / communication ON state to the broadcast ON / communication OFF state.

[0118] When transitioning from this broadcast ON / communication ON state to the broadcast ON / communication OFF state, if the presentation of the broadcast content is switched from delayed presentation to normal presentation, discontinuous presentation of the broadcast content or missing parts of the broadcast content presentation may occur.

[0119] For this reason, the receiving device 1 may be configured to provide the viewer with a synchronous presentation notification that includes the occurrence of discontinuous presentation of broadcast content, the occurrence of partial loss of presentation of broadcast content, and the like.

[0120] The control unit 51 determines the content, timing, or period of the synchronous presentation notification and instructs the content generation unit 31. Then, the content generation unit 31 performs notification of the instructed content at the instructed timing or period.

[0121] (10) In the first embodiment, a case where broadcast content and communication content are presented in synchronization with each other is described using FIG. 1, but this is not limited to this, and may be, for example, as follows.

[0122] When one content is transmitted over two different transmission paths, the receiving device may be configured as shown in Fig. 9, in which the content received from the two transmission paths is synchronized and decoded by one decoder. However, in Fig. 9, the same reference numerals are used for components that perform substantially the same processing as the components in Fig. 1.

[0123] 9, a decoding unit 14A receives the outputs of buffers 13 and 22, decodes the input data from each buffer, and outputs the decoded data to a content generation unit 31A. The content generation unit 31A receives the output of decoding unit 14A and generates presentation content for the service using the input data in accordance with instructions from a control unit 51.

[0124] When transmitting the main video via broadcasting and the extended information via communication, the receiving device may be configured as shown in Fig. 10, in which the main video is decoded by one decoding unit and the main video and extended video are decoded by another decoding unit. However, in Fig. 10, the same reference numerals are used for the constituent units that perform substantially the same processing as the constituent units in Fig. 1.

[0125] 10, a decoding unit 14B receives the output of the buffer 13 as input, decodes the input data, and outputs the decoded data to a content generation unit 31B. The content generation unit 31B receives the output of the decoding unit 14B as input, generates presentation content such as non-extended video using the input data in accordance with instructions from a control unit 51, and outputs the presentation content to a presentation unit 5.

[0126] The decoding unit 23B receives the outputs of the buffer 13 and the buffer 22, decodes the input data, and outputs the decoded data to the content generation unit 32B. The content generation unit 32B receives the outputs of the decoding units 14B and 23B, and generates presentation content such as an extended video using the input data from each unit in accordance with instructions from the control unit 51, and outputs the content to the presentation unit 5B.

[0127] In either case of FIG. 9 or FIG. 10, it is possible to apply substantially the same content as the synchronous presentation method and synchronous presentation notification in the synchronous presentation method described in the first embodiment and the supplement to the first embodiment.

[0128] (11) Even if there is a time difference between reception of broadcast and communication, depending on the content, there may be cases where synchronization between broadcast and communication is not necessary, and there is also the option of not performing synchronization control between broadcast and communication. In this case, the control unit 51 may determine whether or not to perform synchronization control between broadcast and communication.

[0129] The necessity of synchronization may be determined by the receiving device, or the delay tolerance may be specified for each content and communicated to the receiving device by the broadcaster, a business associated with the broadcaster, or another business via broadcasting or communication. The delay tolerance may be sent in the AIT, within an application that can be identified by the AIT, or in the control information (SI) of the broadcast signal.

[0130] (12) The buffer configuration in the receiving device 1 described in the first embodiment with reference to FIGS. 1 and 2 is an example, and is not limited to this configuration as long as the buffer has the same functions as those in the first embodiment.

[0131] For example, it is desirable to place the buffer in a position where the memory size can be minimized. Also, in the first embodiment, a buffer is provided for each function, such as a PES buffer, a synchronization buffer, and a reorder buffer, but this is not limited to this, and one buffer may be provided with multiple functions. Also, the memory allocation that the buffer allocates to each function may be dynamic, or multiple functions may be realized by sharing memory.

[0132] The same can be said for the receiving devices 1A and 1B described with reference to FIGS.

[0133] (13) In the first embodiment, the synchronization control of broadcasting and communication is described, but the linked systems are not limited to the link between broadcasting and communication, and may be the link between broadcasting and broadcasting, the link between communication and communication, or the link between signals based on three or more transmission paths.

[0134] (14) In the first embodiment, the packet structure defined in the MPEG2-TS system is used for explanation, but the multiplexing method is not particularly limited. Examples of multiplexing methods include MP4, RTP, MMT, etc., which are widely used for streaming.

[0135] (15) In the broadcasting and communication cooperation service, a service has been proposed in which a receiving device cooperates with a content presentation device, which is a communication terminal such as a smartphone or a tablet.

[0136] In this case, it is necessary to control synchronization between the content presented by the receiving device 1 and the content presented by the content presentation device.

[0137] An example of such a service is one in which broadcast content is presented on a receiving device and communication content is presented on a content presentation device.

[0138] However, services in which a receiving device and a content presentation device cooperate with each other are not limited to this. For example, there are (A) a service in which communication content is presented by a receiving device and broadcast content is presented by a content presentation device, (B) a service in which broadcast content and a portion of the communication content are presented by a receiving device and a portion of the communication content are presented by a content presentation device, (C) a service in which a portion of broadcast content is presented by a receiving device and a portion of the broadcast content and the communication content are presented by a content presentation device, (D) a service in which a portion of the communication content is presented by a receiving device and a portion of the communication content and the broadcast content are presented by a content presentation device, (E) a service in which a portion of the broadcast content and the communication content are presented by a receiving device and the broadcast content is presented by a content presentation device, and (F) a service in which a portion of the broadcast content and a portion of the communication content are presented by a receiving device and a portion of the broadcast content and a portion of the communication content are presented by a content presentation device.

[0139] In order to realize synchronous control of broadcasting and communication between a receiving device and a content presentation device, it is necessary to notify the other party of control information such as AIT related to synchronization, PTS or DTS or delay time between broadcasting and communication, and synchronous presentation method and synchronous presentation notification as necessary.

[0140] When a receiving device receives a broadcast and a tablet terminal, which is a linked terminal, receives a communication and synchronizes them with each other, it is necessary to notify the receiving device of the PTS of the linked terminal.

[0141] Furthermore, when broadcast content or communication content received by a receiving device is transmitted to a linked terminal, the load on the hardware and software of the linked terminal can be reduced by transmitting the data after synchronization control has been performed by the receiving device. In this case, the receiving device may calculate a delay time occurring in communication between the receiving device and the content presentation device, and control the output timing of PES packets from the PES buffer 71 in the buffer 13 and the PES buffer 71 in the buffer 22, taking into account both the delay time between the reception time of the communication content and the reception time of the broadcast content and the delay time occurring in communication between the receiving device and the content presentation device.

[0142] In either case, the control unit 51 determines the synchronous presentation method and the content and timing or period of the synchronous presentation notification, and instructs the content generation unit, while notifying the linked terminal of the determined content via the communication transmission / reception unit 41.

[0143] (16) Depending on the type of application and content, there are many use cases and synchronized presentation methods for synchronizing communication and broadcasting.

[0144] The control unit 51 has a function to provide multiple synchronous presentation methods and a function to control the presentation method related to the synchronous presentation according to the synchronous presentation method, and presents to the viewer multiple synchronous presentation methods that can be selected depending on the application or content.

[0145] The viewer selects from among a plurality of selectable synchronized presentation methods by operating the input interface. The selection is then input to and set in the control unit 51. Note that the control unit 51, operation input unit 42, content generation unit 31, and presentation unit 5 perform a series of operations related to the setting in cooperation with each other.

[0146] An example of the settings menu is shown in Figure 11.

[0147] In the example of FIG. 11, the broadcasting / communication cooperation menu allows for animation settings and synchronous presentation method settings.

[0148] The animation settings allow you to set the animation when connecting two discontinuous images, for example, in a synchronous screen transition.

[0149] The synchronous presentation method setting allows you to set the synchronous presentation method. An example of the synchronous presentation method setting screen is shown in Figure 12. In the synchronous presentation method setting, viewers can select from a variety of synchronous presentation methods (Type 1, Type 2) that can be presented to them, including receiver-selected mode, broadcaster-selected mode, manual mode, and OFF (no synchronous presentation).

[0150] When the viewer selects the broadcast station automatic mode, the control unit 51 executes the synchronous presentation method described in the AIT only if the synchronous presentation method is set in the AIT.

[0151] When a viewer selects the receiver-selected mode, the control unit 51 selects a synchronous presentation method from among synchronous presentation methods that can be presented to the viewer or synchronous presentation methods described in the AIT, and executes the selected synchronous presentation method. Note that the selection of the synchronous presentation method may be performed dynamically.

[0152] In addition to specifying the synchronous presentation method in the AIT, there are other methods such as specifying the method within an application that can be identified by the AIT, and specifying the method using control information (SI, etc.) of the broadcast signal.

[0153] When a viewer selects manual mode, a manual setting screen, an example of which is shown in FIG. 13, appears. In the example of the manual setting screen in FIG. 13, the viewer can set the delay time between -MAX seconds and +MAX seconds out of the range of -10 seconds to +10 seconds. The maximum delay time value is determined by the control unit 51 based on the size of the content data, the size of the buffer, and the like. The synchronization delay time calculated from the PTS is also displayed as a recommended value. The viewer can change the delay time setting by moving the position of the black arrow in the figure. The viewer can also return the delay time to the recommended value determined by the control unit 51 by pressing the recommended value button. The viewer can also set the delay time to 0 by pressing the reset button (switching to normal presentation with no delay).

[0154] When the viewer performs an operation to change the delay time setting, a control signal indicating the delay time is output to the control unit 51. The control unit 51 controls the buffer based on the control signal to adjust the delay.

[0155] (17) The functions of the control unit 51 described in this embodiment may be implemented as software or an application. Also, some of the functions may be packaged as an API (Application Programming Interface).

[0156] (Findings that formed the basis of the invention 2) The receiving device described in Patent Document 3 receives broadcast content from a digital broadcast signal and receives communication content linked to the broadcast content from a communication network. The receiving device then delays presentation of the broadcast content based on the difference between the PTS of the broadcast content and the PTS of the communication content.

[0157] In communication networks such as the Internet, jitter occurs along the transmission path, and the jitter must be compensated for on the receiving side. Therefore, a receiving device for communication requires a de-jitter buffer to compensate for the jitter. On the other hand, a receiving device for broadcast does not require a de-jitter buffer. A receiving device that functions as a broadcast / communication integrated receiving device that integrates broadcast and communication must include a de-jitter buffer for communication, and a delay buffer for broadcast that realizes a buffer delay equivalent to the buffer delay of the de-jitter buffer, thereby matching the playback times of communication and broadcast.

[0158] As described above, the receiving device described in Patent Document 3 synchronizes broadcast content and communication content based on the difference between the PTS of the broadcast content and the PTS of the communication content. If a large-capacity buffer is used for synchronization, it becomes possible to compensate for jitter without underflow or overflow.

[0159] However, increasing the buffer capacity poses a problem of increasing the end-to-end delay. Conventional broadcast receiving systems are required to minimize the end-to-end delay, and even if the receiving device has sufficient surplus memory, it is not realistic to use all of the memory for jitter compensation. It is therefore desirable to use the minimum amount of memory necessary. Furthermore, when a system decoder model is specified to ensure synchronous playback and buffer management during decoding in the receiving device, it is necessary to ensure the operation of the receiving device by using a buffer of a predetermined size.

[0160] In a receiving device that functions as a broadcast / communication cooperative receiving device, when a buffer of a predetermined size is used to control the de-jitter buffer, there is a high possibility that underflow and overflow will occur, and as a countermeasure against underflow, for example, further buffering of communication content will be necessary. When the receiving device described in Patent Document 3 is used, the delay time of the broadcast delay buffer is affected by the control of the de-jitter buffer, causing overflow or underflow in the broadcast delay buffer, affecting content viewing and making it difficult to guarantee the operation of the broadcast receiver.

[0161] Therefore, the inventors have studied technical solutions to this problem, and as a result of this study, embodiments based on the solutions that the inventors have arrived at will be described below.

[0162] (Embodiment 2) FIG. 14 is a block diagram showing a configuration of a receiving device 100 which is a broadcast and communication cooperative receiving device according to the second embodiment of the present invention.

[0163] The receiving device 100 includes a digital broadcast receiving unit 111, a separation unit 112, a delay buffer 113, a separation buffer 114, a decoding unit 115, a communication transmitting / receiving unit 121, a separation unit 122, a de-jitter buffer 123, a separation buffer 124, a decoding unit 125, a content generating unit 131, a control management unit 141, and a control unit 151.

[0164] The digital broadcast receiving unit 111 receives as input a digital broadcast signal received by an external broadcast antenna 3. The digital broadcast receiving unit 111 then selects a desired channel from the digital broadcast signal, performs demodulation processing, error correction processing, etc. on the digital broadcast signal of the selected desired channel, generates a transport stream, and outputs it to the separating unit 112.

[0165] The separator 112 separates the transport stream generated by the digital broadcast receiver 111 into video data, audio data, subtitle data, etc., and outputs them to the delay buffer 113. The separator 112 also acquires various control information contained in the transport stream, outputs the PCR to the controller 151, and outputs control information including information related to the type of content and control to the control manager 141.

[0166] Delay buffer 113 is a buffer for realizing a buffer delay equivalent to the buffer delay of de-jitter buffer 123. Delay buffer 113 adjusts the delay of content data for each component, such as video data and audio data, output from demultiplexer 112 in accordance with input / output timing instructed by control unit 151, and outputs the adjusted data to demultiplexer buffer 114.

[0167] The separation buffer 114 stores the video data, audio data, etc. output from the delay buffer 113, and outputs elementary streams (ES) for each component such as video and audio in units of access units to the decoding unit 115 with their output timing aligned based on timestamp information such as DTS obtained from the PES header of the PES packet. The separation buffer 114 also outputs timestamp information such as DTS obtained from the PES header to the control unit 151. The separation buffers 114 and 124 have the same function as the Elementary Stream Buffer in the MPEG2 system.

[0168] The decoding unit 115 decodes the access units for each component such as video and audio output from the separation buffer 114 and outputs them to the content generation unit 131 .

[0169] The communication transmitting / receiving unit 121 acquires AV content from a content server provided by a company related to the broadcasting company or another company via a communication network, and outputs the acquired AV content to the separation unit 122. The AV content provided by the communication company includes file data, video data, audio data, and the like.

[0170] Separation unit 122 separates the AV content input from communication transmission / reception unit 121 into video data, audio data, etc., and outputs the data to de-jitter buffer 123. Separation unit 122 also outputs control information to control management unit 141, the control information including information related to the type of content and control included in the AV content.

[0171] De-jitter buffer 123 is a buffer for absorbing jitter due to the transmission path. De-jitter buffer 123 adjusts the delay of content data for each component, such as video data and audio data, output from demultiplexer 122 at input / output timing instructed by control unit 151, and outputs the adjusted data to demultiplexer buffer 124.

[0172] Separation buffer 124 stores the video data, audio data, etc. output from de-jitter buffer 123, and based on timestamp information such as DTS obtained from the PES header of the PES packet, aligns the output timing of elementary streams for each component such as video and audio, and outputs them to decoding unit 115 in access unit units. In addition, separation buffer 124 outputs timestamp information such as DTS obtained from the PES header to control unit 151.

[0173] The decoding unit 125 decodes the access units for each component such as video and audio output from the separation buffer 124 and outputs them to the content generation unit 131 .

[0174] The content generation unit 131 generates presentation content using the content data of each component (video, audio, subtitles, etc.) output from the decoding unit 115 and the content data of each component (video, audio, subtitles, etc.) output from the decoding unit 125. The presentation content generated by the content generation unit 131 is output to the external presentation unit 5 and presented by the presentation unit 5.

[0175] Control management unit 141 determines a control method for delay buffer 113 and de-jitter buffer 123 based on the type of content and control-related information included in the control information, and the states of delay buffer 113 and de-jitter buffer 123, and instructs control unit 151 on the determined control method. Control management unit 141 will be described further below using FIG. 15.

[0176] The control unit 151 generates a reference clock signal using the PCR output from the separation unit 112. This generated reference clock signal is used to control the output timing of each buffer, etc.

[0177] The control unit 151 controls the delay of the delay buffer 113 and the de-jitter buffer 123 based on timestamp information such as DTS output from the separation buffer 114, timestamp information such as DTS output from the separation buffer 124, and the control method determined by the control management unit 141.

[0178] An example of the configuration of the control management unit 141 will be described below with reference to FIG.

[0179] FIG. 15 is a block diagram showing an example of the configuration of the control management unit 141 in FIG.

[0180] The control management unit 141 includes a control information extraction unit 171 , a buffer management unit 172 , a monitoring unit 173 , and a control method determination unit 174 .

[0181] The control information extraction unit 171 extracts information related to the type of content and control from the input control information, and outputs the extracted information related to the type of content and control to the control method determination unit 174. However, the information related to the type of content and control includes, for example, information related to the accuracy required for content synchronization and information related to the allowable end-to-end delay time of broadcast content. Note that the control information such as the information related to the type of content and control is multiplexed and transmitted, for example, on the transmitting side. For example, when the MPEG2-TS method is used as the multiplexing method, the control information is PSI, SI, sections, etc., which are composed of descriptors, tables, etc.

[0182] The buffer management unit 172 manages the buffer size, buffer occupancy, and delay time (the time from input to output from the buffer) for each of the delay buffer 113 and the de-jitter buffer 123, and calculates the size of the available surplus buffer based on these.

[0183] For example, buffer management section 172 can constantly monitor the input clock and output clock, and calculate the delay time and buffer occupancy in de-jitter buffer 123 and delay buffer 113, respectively.

[0184] Furthermore, buffer management section 172 can calculate the buffer occupancy in each of de-jitter buffer 123 and delay buffer 113 by multiplying the average bit rate by the delay time in the buffer.

[0185] If there is a buffer memory that is shared and managed in addition to delay buffer 113 and de-jitter buffer 123, buffer management section 172 may dynamically determine the buffer size including the available memory therein.

[0186] Monitor 173 constantly monitors the possibility of occurrence of underflow and overflow in de-jitter buffer 123, and notifies control method determiner 174 of the monitoring result.

[0187] Here, an example of the monitoring process performed by the monitoring unit 173 in the second embodiment will be described.

[0188] Monitor 173 monitors the buffer occupancy of de-jitter buffer 123 .

[0189] Then, when the buffer occupancy of de-jitter buffer 123 is less than a predetermined first threshold, monitoring unit 173 determines that there is a possibility of underflow occurring and turns on an underflow flag. On the other hand, when the buffer occupancy of de-jitter buffer 123 is equal to or greater than the predetermined first threshold, monitoring unit 173 determines that there is no possibility of underflow occurring and turns off the underflow flag.

[0190] Furthermore, when the buffer occupancy of de-jitter buffer 123 exceeds a predetermined second threshold, monitoring unit 173 determines that an overflow may occur and turns on an overflow flag. On the other hand, when the buffer occupancy of de-jitter buffer 123 is equal to or less than the predetermined second threshold, monitoring unit 173 determines that an overflow may not occur and turns off the overflow flag.

[0191] The monitoring unit 173 performs the above operation at all times.

[0192] When there is a possibility of an underflow or an overflow occurring, control method determination unit 174 determines a control method for delay buffer 113 and de-jitter buffer 123 based on the surplus buffer size, end-to-end delay, content type, control-related information, etc., and notifies control unit 151 of the determined control method. The operation of control method determination unit 174 will be described further below using FIG. 17.

[0193] Figure 16 is a flowchart showing an example of the initial operation of delay buffer 113 and de-jitter buffer 123 after receiving device 100 of Figure 14 starts receiving broadcast communication. However, in the flowchart of Figure 16, it is assumed that underflow and overflow do not occur in delay buffer 113 and de-jitter buffer 123. In Figure 16, communication-related processing is shown on the left side of the figure, and broadcast-related processing is shown on the right side of the figure.

[0194] The receiving device 100 starts receiving a broadcast (step S101) and starts receiving a communication (step S102).

[0195] After communication reception starts, de-jitter buffer 123 starts buffering communication data under the control of control unit 151 (step S103). Control unit 151 controls the start of buffering by delay buffer 113 in synchronization with the start of buffering by de-jitter buffer 123, and delay buffer 113 starts buffering broadcast data under the control of control unit 151 (step S104).

[0196] Control unit 151 determines whether the buffering amount of de-jitter buffer 123 has reached the initial buffering amount, that is, whether the initial buffering of de-jitter buffer 123 has been completed (step S105). Until it is determined that the initial buffering of de-jitter buffer 123 has been completed (S105: No), the initial buffering of de-jitter buffer 123 and delay buffer 113 is performed, and the process of step S105 is performed.

[0197] If it is determined that the initial buffering of de-jitter buffer 123 is completed (S105: Yes), control unit 151 controls the start of delayed output of data from de-jitter buffer 123 and delay buffer 113. De-jitter buffer 123 starts delayed output of communication data under the control of control unit 151 (step S106), and delay buffer 103 starts delayed output of broadcast data under the control of control unit 151 (step S107).

[0198] As described above, delay buffer 113 is operated in accordance with the operation of de-jitter buffer 123, and the initial operation is completed.

[0199] However, the initial buffering amount of de-jitter buffer 123 is, for example, a value obtained by multiplying the estimated time of jitter to be compensated for by the average bit rate.

[0200] The output of normal broadcast data before the delayed output is started may start after the initial buffering of de-jitter buffer 123 is completed, or may start without waiting for the initial buffering of de-jitter buffer 123 to be completed.

[0201] When de-jitter buffer 123 starts outputting, communication data is output that is timed to match the broadcast data based on the time difference calculated from the time stamp information of the broadcast data and communication data.

[0202] In Figure 16, it is explained that the size of the delay buffer 113 is large enough to delay the broadcast, but if the delay buffer 113 is about to overflow before the delayed output of the broadcast data begins, appropriate processing must be performed at that time.

[0203] Fig. 17 is a flowchart showing an example of the control method determination operation by control method determination section 174 of Fig. 14. However, at the start of the flowchart of Fig. 17, it is assumed that de-jitter buffer 123 and delay buffer 113 are in a steady state where they are synchronized.

[0204] Control method determination unit 174 determines whether an underflow flag based on the result of monitoring of de-jitter buffer 123 by monitor 173 is ON or OFF (step S151). If the underflow flag is OFF, that is, if there is no possibility of underflow occurring in de-jitter buffer 123 (S151: OFF), control method determination unit 174 determines whether an overflow flag based on the result of monitoring of de-jitter buffer 123 by monitor 173 is ON or OFF (step S152).

[0205] If the overflow flag is OFF, that is, if there is no possibility of an overflow occurring in de-jitter buffer 123 (S152: OFF), the process returns to step S151.

[0206] If the overflow flag is ON, that is, if there is a possibility of an overflow occurring in de-jitter buffer 123 (S152: ON), control method determination unit 174 determines the control method to be a process for overflow (for example, a process for skipping the output of de-jitter buffer 123) and instructs control unit 151. Control unit 151 receives this instruction and executes the process for overflow on de-jitter buffer 123 (step S153).

[0207] If the underflow flag is ON, that is, if there is a possibility of underflow occurring in de-jitter buffer 123 (S151: ON), control method determination unit 174 determines whether or not there is room in de-jitter buffer 123 (step S154). In step S154, for example, it is determined that there is room in de-jitter buffer 123 if the surplus buffer size of de-jitter buffer 123 calculated by buffer management unit 172 is equal to or greater than a predetermined value.

[0208] If it is determined that de-jitter buffer 123 does not have room (S154: No), the process proceeds to step S162.

[0209] On the other hand, if it is determined that de-jitter buffer 123 has room to spare (S154: Yes), control method determination unit 174 determines whether delay buffer 113 has room to spare (step S155). In step S155, for example, it is determined that delay buffer 113 has room to spare if the surplus buffer size of delay buffer 113 calculated by buffer management unit 172 is equal to or greater than a predetermined value.

[0210] If it is determined that there is no room in the delay buffer 113 (S155: No), the process proceeds to step S162.

[0211] If it is determined that delay buffer 113 has room (S155: Yes), control method determination unit 174 instructs control unit 151 to perform additional buffering in de-jitter buffer 123, and control unit 151, upon receiving this instruction, performs control to stop the output of de-jitter buffer 123 and perform additional buffering. De-jitter buffer 123 stops output under the control of control unit 151 and performs additional buffering (step S156).

[0212] Control method determination unit 174 determines whether or not additional buffering in de-jitter buffer 123 is complete (step S157). Completion of additional buffering is determined, for example, based on the result of monitoring de-jitter buffer 123 by monitoring unit 173, when it is determined that the occupancy of the de-jitter buffer is sufficient and that there is little possibility that the de-jitter buffer will underflow again.

[0213] If it is determined that additional buffering by de-jitter buffer 123 is not completed (S157: No), the process returns to step S154.

[0214] If it is determined that additional buffering in de-jitter buffer 123 is complete (S157: Yes), control method determination unit 174 determines whether or not it is necessary to delay the broadcast (step S158). The determination in step S158 is that it is not necessary to delay the broadcast when, for example, the information related to the accuracy required for content synchronization indicates that synchronization is not necessary.

[0215] If it is determined that there is no need to delay the broadcast (S158: No), the control method determination unit 174 determines the control method to be one that does not perform delay control of the delay buffer 113, and notifies the control unit 151 of the determined control method. Upon receiving this notification, the control unit 151 does not perform delay control of the delay buffer 113, and the delay buffer 113 outputs the broadcast data without delaying it (step S159).

[0216] If it is determined that the broadcast needs to be delayed (S158: Yes), the control method determination unit 174 uses information related to the allowable end-to-end delay time of the broadcast content to determine whether the actual end-to-end delay time is within an allowable range (step S160). For example, the information related to the allowable end-to-end delay time of the broadcast content can be obtained by specifying the allowable end-to-end delay time of the content on the transmitting side and transmitting it as a control signal by broadcasting, and the receiving device can receive the broadcast signal and obtain the information related to the allowable end-to-end delay time of the broadcast content from the control signal.

[0217] If it is determined that the end-to-end delay time is not within the allowable range (S160: No), the process proceeds to step S162.

[0218] If it is determined that the end-to-end delay time is within the allowable range (S160: Yes), control method determination unit 174 determines the control method to be the control method for performing delay control of delay buffer 113, and notifies control unit 151 of the determined control method. Control unit 151 receives this notification and performs delay control of delay buffer 113, and delay buffer 113 performs delayed output operation of broadcast data (step S161). The amount of delay in delay buffer 113 during delay control can be calculated by using input / output counters of de-jitter buffer 123 and delay buffer 113.

[0219] In step S162, control method determination unit 174 determines that synchronization between broadcasting and communication is impossible. Then, control method determination unit 174 determines a control method for independently controlling de-jitter buffer 123 and delay buffer 113 so as to guarantee only the broadcast reception operation, and notifies control unit 151 of the determined control method. Control unit 151 receives this notification and independently controls de-jitter buffer 123 and delay buffer 113 (step S162).

[0220] (Supplementary note to the second embodiment) The following provides supplementary information about the second embodiment.

[0221] (1) In the second embodiment, when there is a delay difference due to the transmission path between broadcasting and communication, the receiving device can be configured as shown in Fig. 18. However, in Fig. 18, the same reference numerals are used for the constituent units that perform substantially the same processing as the constituent units in Fig. 14.

[0222] The receiving device 100A of Figure 18 is configured by adding a synchronization buffer 191 between the delay buffer 113 and the separation buffer 114, and adding a synchronization buffer 196 between the de-jitter buffer 123 and the separation buffer 124, compared to the receiving device 100 of Figure 14.

[0223] The control unit 151 uses timestamp information such as DTS from the separation buffer 114 and timestamp information such as DTS from the separation buffer 124 to control the output timing of the synchronization buffer 191 and the synchronization buffer 196 so that synchronization is achieved between the broadcast data and the communication data.

[0224] (2) Even if there is a possibility that de-jitter buffer 123 may underflow or overflow, it is not necessarily necessary to control delay buffer 113.

[0225] (3) The mechanism for determining the control method described in the second embodiment can be used when various methods for avoiding underflow or overflow are used.

[0226] (4) In the second embodiment, if a buffer size for ensuring buffer operation is specified in advance, the surplus buffer size may be calculated using the specified buffer size.

[0227] If it is not possible to control de-jitter buffer 123 and delay buffer 113 with the specified buffer size, reception operation regarding communication does not need to be guaranteed.

[0228] If control is not possible with the specified buffer size, a message indicating this may be displayed on the display unit 5, for example.

[0229] If control is not possible with the specified buffer size, information indicating this may be fed back to the transmitting side using communication means.

[0230] Information relating to the transmission path, such as the actual jitter time and the delay time between broadcasting and communication, may be fed back to the transmitting side using a communication means.

[0231] (5) When synchronization between broadcasting and communication cannot be guaranteed, it is preferable to perform control that gives priority to broadcasting-related operations of the receiving device.

[0232] If synchronization between broadcasting and communication cannot be guaranteed, the operation of the receiving device with respect to broadcasting is guaranteed by appropriately controlling de-jitter buffer 123 and delay buffer 113 while monitoring de-jitter buffer 123.

[0233] (6) As a result of the control of de-jitter buffer 123, it is also possible to change the communication content to data with less delay and jitter. In this case, communication transmitting / receiving unit 121 notifies the content server of this, and data with less jitter is obtained. This makes it possible to provide stable services to viewers.

[0234] It is also assumed that a change in the acquisition of communication content may require a change in the method of acquiring broadcast content, in which case the control management unit 141 changes the method of acquiring broadcast content.

[0235] (7) The transmitting side may multiplex and transmit control information indicating the quality of the transmission path as a signaling message, and the receiving device may determine or limit the control method based on the transmitted quality. For example, if the transmitting side signals the maximum delay time expected in the communication transmission path as a control signal indicating the quality of the transmission path, the receiving device may compare the maximum delay time with the buffer size of the receiving device to determine whether to receive the communication content or whether to synchronously play back the broadcast content and the communication content.

[0236] The transmitting side may multiplex and transmit control information indicating a recommended control method as a signaling message, and the receiving device may operate based on the transmitted recommended control method.

[0237] The transmitting side may multiplex and transmit information on the jitter time for which the transmitting side can guarantee operation, and the buffer sizes of de-jitter buffer 123 and delay buffer 113 as a signaling message.

[0238] (8) The accuracy required for content synchronization may be, for example, (A) no synchronization is required for one piece of content with another piece of content, (B) synchronization accuracy within 10 seconds is required, (C) synchronization accuracy within 1 second is required, or (D) synchronization accuracy on a frame-by-frame basis is required.

[0239] Receiving device 100 can freely determine the control method for synchronization and jitter so as to satisfy the accuracy required for content synchronization. This makes it possible to select a control method that matches the specifications and capabilities of the receiving device. For example, if frame-level synchronization is required, high-accuracy control of delay buffer 113 is performed in accordance with de-jitter buffer 123. Furthermore, if synchronization is not required, it is also possible to choose not to control delay buffer 113 in accordance with the control of de-jitter buffer 123. Instead of notifying the minimum required synchronization accuracy, a recommended synchronization accuracy may be transmitted.

[0240] The receiving device can also determine the synchronization accuracy according to the content and decide the control method. For example, if the content is video and subtitles, the synchronization accuracy can be reduced as long as it is at a level that does not cause problems when viewing the subtitles.

[0241] (9) The transmitting side may transmit control information indicating whether one of the contents can be decoded independently or not. For example, if the broadcast cannot be decoded independently, it is necessary to synchronize the broadcast and communication. On the other hand, if the broadcast can be decoded independently, it is also possible to select to display only the broadcast content when synchronization is not possible.

[0242] (10) The transmitting side may specify the allowable jitter and de-jitter buffer amount and transmit them as control signals.

[0243] The content creator may decide the accuracy of synchronization, for example, to "force" or "not force," and send this information on the sending side.

[0244] (11) It is preferable that the control information be available before decoding begins.

[0245] For example, when MMT (MPEG Media Transport) is used as the multiplexing method, the information that can be obtained before the start of decoding may be described in CI (Composition Information), or may be described in an MPT (MMT Package Table) together with a list of assets. In the case of MPEG2-TS, control information such as a PMT (Program Map Table) may be used, or when MPEG-DASH (Dynamic Adaptive Streaming over HTTP) is used, it may be described in an MPD (Media Presentation Description). In the case of other multiplexing systems, any program information that can be obtained by the receiving device before the start of decoding may be used.

[0246] The control information is transmitted via either broadcasting or communication, or both, and control management section 141 acquires and analyzes the control information before decoding begins, and determines the control method for de-jitter buffer 123 and delay buffer 113 .

[0247] (12) A buffer size for compensating for jitter and synchronization between broadcasting and communication may be specified in advance, and constraints for compensating for operation within the specified buffer size may be specified, and buffer operation, such as measures to prevent underflow and overflow, may be determined based on the specified conditions.

[0248] The total size of the de-jitter buffer, delay buffer, and synchronization buffer may be specified, and operations may be guaranteed within the total size.

[0249] (13) The configurations of the receiving devices 100 and 100A shown in Figures 14 and 18 may be modified to decode using one decoding unit as described using Figure 9, or may be modified to include, for example, two content generation units as described using Figure 10.

[0250] (14) The functions described in the second embodiment and the supplement to the second embodiment may be realized by hardware or software. Also, some may be realized by hardware and some may be realized by software.

[0251] (15) Content for which jitter or synchronization between broadcasting and communication has been eliminated may be transmitted to a linked device such as a tablet before being decoded.

[0252] (16) Some of the functions described in the second embodiment and the supplement to the second embodiment may be realized not only as a receiving device but also as part of the functions of a relay station.

[0253] (17) The control results of the de-jitter buffer 123 and the delay buffer 113 (for example, an error message such as “synchronization between broadcast and communication is not possible”) may be presented to the viewer or recorded as a report.

[0254] (18) The buffer configuration in the receiving device 100 described in the second embodiment with reference to FIG. 14 is an example, and is not limited to this configuration as long as the buffer has the same function as in the second embodiment.

[0255] For example, it is desirable to place the buffer in a position where the memory size can be minimized. Also, in the second embodiment, a buffer is provided for each function, such as delay buffer 113, separation buffer 114, de-jitter buffer 123, and separation buffer 124, but this is not limited to this, and one buffer may be provided with multiple functions. Also, the memory allocation that the buffer allocates to each function may be dynamic, or multiple functions may be realized by sharing memory.

[0256] The same can be said for the receiving device 100A described with reference to FIG.

[0257] (19) In the second embodiment, MPEG2-TS is used as an example of the multiplexing method, but the multiplexing method is not particularly limited. Examples of the multiplexing method include MP4, RTP, MMT, etc., which are widely used for streaming.

[0258] (others) The contents explained in the first embodiment and the supplement to the first embodiment may be combined as appropriate.

[0259] The contents explained in the second embodiment and the supplement to the second embodiment may be combined as appropriate.

[0260] The contents explained in the first embodiment and the supplement to the first embodiment and the contents explained in the second embodiment and the supplement to the second embodiment may be combined as appropriate.

[0261] The contents described in embodiment 1 and the supplement to embodiment 1 may be applied to the contents described in embodiment 2 and the supplement to embodiment 2, and the contents described in embodiment 2 and the supplement to embodiment 2 may be applied to the contents described in embodiment 1 and the supplement to embodiment 1.

[0262] <Summary> The receiving apparatus and receiving method according to the embodiment and the modified example, and their effects will be summarized.

[0263] (1) A first receiving device includes a first buffer that accumulates and outputs a first signal received over a first transmission path that does not require jitter compensation, a second buffer that accumulates and outputs a second signal received over a second transmission path that requires jitter compensation, a control management unit that monitors whether or not an underflow is likely to occur in the second buffer, and if an underflow is likely to occur, determines a control method for the first buffer and the second buffer based on the surplus buffer size of the first buffer and the surplus buffer size of the second buffer, and a control unit that controls the first buffer and the second buffer based on the control method for the first buffer and the second buffer determined by the control management unit.

[0264] The first receiving method is a receiving method performed in a receiving device that includes a first buffer that accumulates and outputs a first signal received over a first transmission path that does not require jitter compensation, and a second buffer that accumulates and outputs a second signal received over a second transmission path that requires jitter compensation, and the receiving method monitors whether or not there is a possibility of underflow occurring in the second buffer, and if there is a possibility of underflow occurring, determines a control method for the first buffer and the second buffer based on the surplus buffer size of the first buffer and the surplus buffer size of the second buffer, and controls the first buffer and the second buffer based on the determined control method for the first buffer and the second buffer.

[0265] According to these, it is possible to improve the quality of service of the first signal that does not require jitter compensation and the second signal that requires jitter compensation.

[0266] (2) In the second receiving device, the control management unit in the first receiving device further determines the control method based on control information relating to the accuracy required for synchronization between the first signal and the second signal.

[0267] (3) In the third receiving device, the control management unit in the first receiving device further determines the control method based on information relating to the allowable end-to-end delay time of the first signal.

[0268] (4) A fourth receiving device includes a first buffer that accumulates and outputs a first signal received from a first transmission path, a second buffer that accumulates and outputs a second signal received from a second transmission path, a control unit that performs synchronization control of the first buffer and the second buffer regarding synchronization between the first signal and the second signal based on time information included in the first signal and time information included in the second signal, and a notification unit that performs notification regarding synchronization in accordance with the synchronization control by the control unit.

[0269] The second receiving method is a receiving method performed in a receiving device that includes a first buffer that accumulates and outputs a first signal received from a first transmission path, and a second buffer that accumulates and outputs a second signal received from a second transmission path, and performs synchronization control of the first buffer and the second buffer related to synchronization between the first signal and the second signal based on time information included in the first signal and time information included in the second signal, and performs a notification related to synchronization in accordance with the synchronization control.

[0270] According to these, it is possible to reduce the sense of incongruity and discomfort felt by the viewer when the first signal and the second signal are synchronized.

[0271] (5) In a fifth receiving device, the control unit performs the synchronization control based on input contents from a viewer.

[0272] This allows the synchronization between the first and second signals to be in line with the viewer's wishes.

[0273] (Embodiment 3) In the embodiments described so far, examples have been described in which the receiving device does not select the communication content, such as when acquiring communication content that has been multicast-streamed. In embodiment 3, an example will be described in which communication content selected by the receiving device is presented synchronously with broadcast content.

[0274] In the following third embodiment, when simply referring to a "receiving device," any of the receiving devices described in Figures 1, 9, 10, and 14 may be used. The same applies to the description of components of the receiving device, such as a "control unit."

[0275] [overview] Below, we will explain an overview of the operations performed by the receiving device and server according to embodiment 3. Note that the server is an example of a transmitting device, and in the following embodiment 3, when the term "server" is used in relation to a function that can be realized by both a communication server and a broadcast server, it may be either a communication server or a broadcast server. The server transmits control information including information on whether the communication protocol is multicast and whether the content is live. The receiving device determines whether it can acquire the communication content at any time based on the control information and whether the content to acquire is available on the communication server. If the receiving device can acquire communication content at any time, the receiving device determines the time and acquisition timing of the communication content to be acquired and acquires it from the server. The receiving device pre-buffers the communication content if it can acquire the communication content for a given time. The server notifies the receiving device of the timing of pre-buffering as control information or an event, and the receiving device starts pre-buffering at the notified time. The receiving device determines whether synchronous playback of broadcast content and communication content is possible based on the buffer status, content type, transmission path status, etc. If there is a possibility that synchronous playback will be impossible, the receiving device controls the buffer or makes a determination based on the acquisition of communication content and performs control based on that determination. The server signals the required accuracy for synchronizing broadcast content with communication content and the allowable time difference between content presentation as control information. The receiving device controls the presentation method and buffer based on the control information. The server signals the accuracy required for synchronizing broadcast content and communication content and the allowable time difference for content presentation as control information, and instructs the communication server on the communication content to be acquired based on the control information.

[0276] [detail] The following describes in detail the operations performed by the receiving device and the server according to the third embodiment.

[0277] For example, in a progressive download method such as MPEG-DASH, content of different quality may be selected depending on the communication environment. Also, data of a desired time may be selected and acquired from segmented data, or communication content may be selected for acquisition using a protocol such as RTSP in a streaming service.

[0278] In the case of MPEG-DASH, for example, multiple pieces of video data with different image sizes and encoding speeds are prepared on the server for one piece of video content, and the video data is divided into segments. The MPD also contains information about the video data stored on the server.

[0279] The receiving device acquires and analyzes the MPD from the server, determines the data to acquire in consideration of the capabilities of the receiving device and the state of the communication transmission path, and requests the data from the server.The receiving device then acquires the desired video data from the server using the HTTP protocol.

[0280] In the broadcasting and communication cooperation service according to the third embodiment, it is desirable that the receiving device acquires and synchronously plays back communication content in an appropriate manner according to the broadcasting service (broadcasting content). Therefore, in the third embodiment, the receiving device acquires control information related to the acquisition of communication content, and also acquires control information related to broadcasting and communication cooperation, and acquires communication content according to the broadcasting service.

[0281] In order to provide a broadcasting and communication cooperation service, the transmitting side can include in the control information related to broadcasting and communication cooperation the transmission method of the communication content, information related to the communication content service, information indicating whether time information related to the acquisition of the communication content is included, time information or timing information related to the acquisition of the communication content, location information of the communication content, etc. Each piece of information will be explained below.

[0282] The transmission method of the communication content is, for example, the MPEG-DASH method, the MMT method, the RTP method, etc. When the control information related to the broadcasting and communication cooperation includes the transmission method of the communication content, the receiving device acquires the transmission method of the communication content from the control information related to the broadcasting and communication cooperation, and acquires the communication content using a reception method suitable for the transmission method.

[0283] The information relating to the service of the communication content is, for example, information indicating VOD, streaming, or live.

[0284] The information indicating whether time information related to the acquisition of the online content is included is, for example, information indicating that time information or timing information related to the start of the acquisition of the online content is described in the control information. The timing information may be, for example, timing information such as an event message.

[0285] When the control information includes time information related to the acquisition of the communication content, the receiving device acquires the time information, controls the acquisition of the communication content, or selects the communication content to be acquired. When the control information includes information indicating that an event message is being transmitted, the receiving device monitors the event message and controls the acquisition of the communication content in accordance with the event.

[0286] The time information related to the acquisition of the communication content is information for specifying the timing of acquiring the communication content to the receiving device, which is necessary for playing back the communication content in synchronization with the broadcast content.

[0287] The receiving device does not have to acquire the content based on the time information related to the acquisition of the communication content. The decision on whether to acquire the content based on the time information may be made by transmitting a control signal so that the broadcasting station can specify it, or the receiving device may make the decision itself. Furthermore, such a decision may also be made by the viewer.

[0288] Specifically, the time information or timing information relating to the acquisition of the communication content is the following information. Time information or timing information relating to the start of acquiring communication content (information indicating the time or timing at which communication content acquisition should begin in order to synchronize with broadcast content) Time information or timing information regarding the completion of acquisition of communication content (information indicating the time or timing at which acquisition of communication content should be completed in order to synchronize with broadcast content) Time information or timing information related to the playback of communication content (information indicating the time or timing at which communication content should be played in order to synchronize with broadcast content) Time information or timing information indicating the time when communication content can be acquired The time information may be absolute time such as NTP, or may be relative time to a reference time of the broadcast signal (PCR, NTP, etc.) Furthermore, timing information such as an event message may be transmitted as time information related to the acquisition of communication content.

[0289] The location information of the communication content is, for example, information indicating the storage location of the communication content.

[0290] In addition to the above information, the control information may include the following information.

[0291] For example, the information may include information indicating a switch from a broadcast-only program to a broadcast-communication integrated program, or time information indicating a time when the broadcast-communication integrated program will start. A broadcast-communication integrated program is, for example, a program that synchronously plays back broadcast and communication, but may also be a program that does not synchronously play back broadcast and communication.

[0292] Furthermore, when switching from a broadcast-only program to a broadcast-communication integrated program, the receiving side can be notified in advance that the broadcast-communication integrated program will start and the time information for the broadcast-communication integrated program will start before the switch, and program information for the next program can be transmitted in advance to instruct pre-buffering of the communication content. This allows the receiving device to obtain program information in advance from a time before the start of the broadcast program, start obtaining the communication content, and pre-buffer it, enabling smooth synchronized playback of the broadcast-communication integrated program.

[0293] Furthermore, when the state of the combination of transmission paths that constitute a program changes, information indicating the change in state in advance and information indicating the time when the state will change may be included in the control information. Such information may be transmitted using the EIT, or may be described in the information of the next program by setting the current next indicator in the PMT to '0' and transmitted as program information.

[0294] Furthermore, these pieces of information may be described in the AIT and transmitted. For example, in the hybrid cast specification, it is assumed that the descriptor of the PMT information of the next program describes a descriptor ait identifier info() indicating that AIT (application control information) is included. In such a case, the AIT of the next program may be transmitted in advance while the current program is being broadcast. Specifically, a flag indicating whether the AIT has been transmitted in advance may be stored in the descriptor, or information that can identify whether the AIT is related to the current program or the AIT is related to the next program information may be described inside the AIT.

[0295] The control information may also include information indicating that the communication server is in a state where it can provide the online content. In other words, this information is information (acquisition information) indicating that it is in a state where it is possible to acquire the online content. The control information may also include time information at which the online content will be available for provision. In other words, this time information is information (acquisition information) indicating that, by notifying a timing, it will be possible to acquire the online content from that timing onwards. The control information may also indicate acquisition information for multiple online contents, or may indicate a list of online contents that the communication server can provide.

[0296] The control information related to broadcasting and communication cooperation may be described as a descriptor in program information based on a broadcast transmission method, or in program information based on a communication transmission method. Furthermore, the control information related to broadcasting and communication cooperation may be described in program information of other formats. The control information related to broadcasting and communication cooperation may be described in any one of these types of program information, or in multiple pieces of program information.

[0297] Here, the program information will be supplemented.

[0298] For example, program information is described in a PMT when MPEG2-TS is used, but may be described in an MPT when MMT is used, or in an MPD for MPEG-DASH. Also, program information may be described in application control information (Application Information Table) used in hybridcast and the like, and transmitted as a section, or transmitted in a data carousel.

[0299] The program information is transmitted using at least one of a plurality of transmission paths, such as broadcasting and communication. For example, program information based on a communication transmission method may be transmitted using broadcasting.

[0300] In addition, the program information may include information indicating that the program information includes control information related to broadcasting and communication cooperation, or the program information may include information indicating location information that includes control information related to broadcasting and communication cooperation.

[0301] A specific example in which control information relating to broadcasting and communication cooperation is described as a descriptor in program information will be described below.

[0302] When broadcast content is transmitted using the MPEG2-TS format and communication content is transmitted using MPEG-DASH, a descriptor corresponding to control information may be written in a PMT transmitted by broadcasting or in an MPD transmitted by communication. Also, a descriptor corresponding to control information may be written in both a PMT and an MPD, or the MPD may be transmitted by broadcasting or the PMT may be transmitted by communication.

[0303] [Content acquisition example] Next, the operation of acquiring a communication content by the receiving device according to embodiment 3 will be described with reference to a flowchart. Fig. 19 is a flowchart showing an example of the operation of acquiring a communication content by the receiving device according to embodiment 3. Note that the flowchart in Fig. 19 is based on the premise that the communication content can be acquired at any time (a state in which the communication content is ready to be transmitted).

[0304] First, the control unit (receiving device) determines a method for acquiring the communication content based on the transmission method of the communication content and information on the service of the communication content (step S201).

[0305] Next, based on the communication content acquisition method determined in step S201, the control unit acquires control information related to broadcasting, control information related to communication, and control information related to broadcasting and communication cooperation, starting from the entry program information (step S202).

[0306] Next, the control unit acquires the following information for acquiring the communication content (step S203). The control unit acquires information about the content prepared on the server from the control information related to communication. For example, in the case of an MPEG-DASH MPD, the content information includes the image size of the video data, the encoding speed of the video data, and time information of the video data. The control unit acquires information on the quality of the communication transmission path from the communication transmitting / receiving unit 21. The control unit acquires the capabilities of the receiving device required to play the content.

[0307] When only the communication content is played back in the receiving device, the control unit can determine the communication content based on the information for acquiring the communication content. However, in order to synchronously play back the broadcast content and the communication content in the broadcast communication cooperation service, the control unit further acquires information related to the playback of the broadcast content (step S204) and determines the communication content suitable for synchronously playing back the broadcast content.

[0308] Information related to the playback of broadcast content includes, for example, the presentation time and decoding time of the broadcast content such as PTS and DTS, the status of buffers such as delay buffers and de-jitter buffers in the receiving device (buffer size, buffer usage, overflow, underflow, etc.), and end-to-end delay amount.

[0309] In the above step S203, the receiving device may acquire time information or timing information related to the acquisition of the above-mentioned online content (information indicating the timing related to the acquisition of the online content). Also, in the above step S203, the receiving device may acquire information indicating that the online content is available for acquisition (information indicating that the online content is ready in the server). In the third embodiment, this information (information related to the acquisition of the online content, i.e., acquisition information) is received via broadcasting, but may also be received via communication.

[0310] Such acquisition information allows the receiving device to appropriately acquire the communication content in response to reception of the broadcast content. Furthermore, by the receiving device acquiring the communication content in response to the acquisition information, the possibility of discontinuities such as skipping or stopping occurring in the presentation of the broadcast, which is the main content, can be reduced, ensuring stable broadcast viewing.

[0311] Next, the control unit selects the communication content suitable for synchronous playback with the broadcast content based on the information acquired in steps S203 and S204, and acquires the selected communication content from the server (step S205).

[0312] Then, the control unit controls the buffer appropriately according to the acquired communication content, thereby synchronously playing back the broadcast content and the communication content (step S206). Note that the broadcast content is received, for example, in step S206. The buffer control method here has been described in the first and second embodiments, so a description thereof will be omitted.

[0313] The following provides additional details about the processing of step S205. Specifically, in step S205, the control unit acquires the timestamp of the broadcast content, and selects the online content that can be played back in sync with the broadcast content. The control unit then requests the server to acquire the selected online content.

[0314] Furthermore, during synchronous playback of broadcast content and communication content, the buffer status may be monitored and it may be determined that synchronous playback cannot be continued due to buffer overflow or underflow, etc. In such cases, the control unit may be able to continue synchronous playback by controlling the acquisition of communication content. Here, controlling the acquisition of communication content means controlling the acquisition of content (pausing, fast-forwarding, rewinding, etc.).

[0315] The control unit can also continue synchronous playback by acquiring content with a different playback time from the server. Acquiring content with a different playback time means, for example, skipping the acquisition of a communication content and acquiring a communication content with a slower playback time, or rewinding the acquisition of a communication content and acquiring a communication content with a faster playback time. This type of control is effective when jitter or delay in the transmission path changes.

[0316] [Example of steady state operation] Next, a synchronous playback operation including the acquisition of a communication content in a steady state where the de-jitter buffer and the delay buffer are synchronized will be described with reference to Fig. 20. Fig. 20 is a flowchart showing an example of a synchronous playback operation including the acquisition of a communication content.

[0317] 17 described in the second embodiment, if it is determined that synchronous playback of the broadcast content and the online content is difficult, control is performed to ensure only the broadcast reception operation. In contrast, the flowchart in Fig. 20 differs in that even if it is determined that synchronous playback of the broadcast content and the online content is difficult, an attempt is made to further acquire online content that allows synchronous playback.

[0318] In a steady state, the control unit (or control management unit) monitors buffers (such as a delay buffer, a de-jitter buffer, and a synchronization buffer) in the receiving device, and determines whether synchronized playback of the broadcast content and the communication content is difficult based on the state of the buffers (step S251).

[0319] If it is determined that synchronized playback of broadcast communication is difficult through buffer control due to overflow or underflow, etc. (S251: Yes), the control unit selects the communication content to acquire based on the operation flow for acquiring communication content shown in Figure 19 (step S252).

[0320] Next, the control unit determines whether the broadcast content and the selected online content can be synchronously played back (step S253). If it is determined that the broadcast content and the selected online content can be synchronously played back (S253: Yes), the control unit acquires the selected online content (step S254), returns to the steady state, and the processing from step S251 onwards is performed side by side.

[0321] On the other hand, if it is determined in step S253 that synchronous playback is not possible (S253: No), buffer control is performed to ensure only the broadcast reception operation (step S255).

[0322] [Example 1 of pre-buffering] In a broadcasting and communication collaboration service, to achieve highly accurate synchronized playback between broadcast content and communication content, it is advisable to acquire the communication content in advance and play it in synchronization with the broadcast content. This allows for smooth synchronized playback without delaying the broadcast content.

[0323] An example in which a broadcasting and communication cooperative service is started in the middle of a program will be described below. Fig. 21 is a flowchart showing an example of an operation in which a broadcasting and communication cooperative service is started in the middle of a program.

[0324] First, the control unit selects a broadcast program (broadcast station), receives program information corresponding to the service ID of the selected program, and analyzes it (step S300). The program information is, for example, a PMT in the case of an MPEG2-TS format.

[0325] Next, the control unit analyzes the program information and determines whether the selected program is related to a broadcasting and communication cooperation service (step S301). If the program information does not describe that the program is related to a broadcasting and communication cooperation service (S301: No), the control unit receives only the broadcast content (step S307) and plays the broadcast content (step S308).

[0326] If the program information describes that the service is a broadcasting / communication cooperative service (S301: Yes), the control unit determines whether the descriptor relating to the start time of acquiring the communication content contains start time information (information related to the acquisition of the communication content) (step S302). If start time information is present (S302: Yes), the control unit acquires the time. At this time, the control unit also acquires location information of the communication content. Then, the control unit calculates the start time of acquiring the communication content based on the acquired information (if necessary), and starts acquiring the communication content at the calculated time (step S303).

[0327] For example, if the start time of acquiring the communication content is indicated by the broadcasting station's PCR-based time information, the control unit starts acquiring the communication content when the PCR time played on the receiving device matches the PCR time indicated by the start time information.

[0328] Also, for example, if the start time of acquiring the communication content is described as T seconds before the start of the broadcast program, the control unit calculates T seconds before the start time of the broadcast program and starts acquiring the communication content at that time.

[0329] In step S303, a step of determining whether the online content is available for acquisition may be provided. Whether the online content is available for acquisition may be determined by an inquiry from the receiving device to the server, or by transmission of a descriptor of program information or an event message from the server. Furthermore, whether the online content is available for acquisition may be determined by transmission of time information, etc., during which the online content can be acquired.

[0330] In step S302, if there is no information on the start time of acquiring the online content (S302: No), the control unit starts acquiring the online content in response to an input from the viewer, such as a user interface input (step S306). In this case, the control unit may start acquiring the content at a predetermined time, or may calculate the time to acquire the online content and start acquiring it.

[0331] The communication content acquired in advance in step S303 or step S306 is buffered in a memory (buffer) or the like, and is output when the broadcast content is received or the synchronized playback time arrives.

[0332] Following step S303, the control unit receives the broadcast content (step S304) and performs synchronous playback of the broadcast content and the communication content (step S305).

[0333] In addition, even if it is determined in step S302 that there is information on the start time of acquisition of the communication content, a determination step may be provided to determine whether to pre-acquire the communication content based on the playback capabilities, buffer performance, etc. of the receiving device.

[0334] Note that the descriptor including the control information (here, information on the start time of content acquisition) described in the example of Fig. 21 may be described in the same program information or in different program information. It may be transmitted over at least one of multiple broadcast or communication transmission paths. If transmitted over different transmission paths, information indicating the location of the program information is described in the program information that serves as an entry.

[0335] Also, in the example of FIG. 21, the control information is described as a descriptor, but the control information may also be transmitted as an event message.

[0336] 21, the broadcasting and communication cooperation service was started in the middle of a broadcast program, but if the broadcasting and communication cooperation service is to be started from the beginning of the next broadcast program, it is necessary to obtain the communication content before the start of the next broadcast program. In this case, the program information of the next program is transmitted while the previous program is being provided.

[0337] When the receiving device receives the program information of the next program, the receiving device determines whether or not it is possible to acquire the communication content of the next program in advance, and acquires the communication content in advance. At this time, the previous program information may include information indicating that the provision of the next program information has begun or location information, so that the receiving device recognizes the existence of the communication content and starts acquiring the program information.

[0338] [Example 2 of pre-buffering] The buffering operation of communication content will be described using the hybridcast specification standardized by the IPTV Forum and ARIB as an example. Fig. 22 is a flowchart showing an example of the buffering operation of communication content. In the example of Fig. 22, information on the acquisition start time of the communication content is notified as an event using a control code of the AIT.

[0339] First, the control unit selects a broadcast program (broadcast station), receives the PMT of the selected program, and analyzes it (step S351). Next, the control unit determines whether the PMT contains a descriptor ait_identifier_info() indicating that an AIT has been transmitted (step S352). If the descriptor does not exist, that is, if an AIT has not been transmitted (S352: No), the control unit receives only the broadcast content (step S353) and plays back the received broadcast content (step S354).

[0340] If the descriptor is present (S352: Yes), the control unit starts acquiring and monitoring the AIT (step S355). Specifically, the control unit analyzes the AIT and acquires location information of the application, acquisition start time information of the communication content, and location information included in the AIT.

[0341] Next, the control unit monitors the application control code of the AIT (step S356), and monitors the application pre-acquisition flag (PREFECH command in the Hybridcast specification), that is, determines whether the application pre-acquisition flag is present (step S357).

[0342] If the application pre-acquisition flag is present (S357: Yes), the control unit pre-acquires the application (step S360) and returns to the processing of step S356. If the application pre-acquisition flag is not present (S357: No), the control unit monitors the online content pre-acquisition flag (PREBUFFER command in the Hybridcast specification), that is, determines whether the online content pre-acquisition flag is present (step S358). Note that if there is no information on the start time of acquisition of the online content in step S355, the monitoring of the online content pre-acquisition flag in step S358 does not have to be performed.

[0343] If the communication content advance acquisition flag is present (S358: Yes), the control unit advances the communication content from the server and buffers it, and returns to the process of step S356. If the communication content advance acquisition flag is not present (S358: No), the control unit monitors the application execution flag (AUTOSTART command in the Hybridcast specification), that is, determines whether the application execution flag is present (step S359).

[0344] The processes of steps S356 to S358, S360, and S361 are repeated until the application execution flag is set in step S359 (S359: No). If the application execution flag is set (S359: Yes), the control unit acquires the application from the location specified by the location information described in the AIT (step S362). At this time, if the application has been acquired in advance in step S360, the process here is skipped.

[0345] Next, the control unit executes the application (step S363) and acquires the communication content from the location specified by the location information of the communication content (step S364). At this time, if the communication content has been acquired in advance in step S361, the process here is skipped.

[0346] Finally, the control unit receives the broadcast content (step S365), and synchronously plays back the broadcast content and the communication content (step S366).

[0347] Note that the operations related to the applications and online content described in the operation example of Fig. 22 may be realized as a single application, or may be realized as separate applications. For example, acquisition of online content may be executed as part of a single application, or an application for acquiring the online content and an application for playing the online content may be provided separately and executed separately. In this case, the application for acquiring the online content is launched first, and the application for playing the online content is launched at a different timing.

[0348] Furthermore, the location information of the communication content may be described in the AIT or may be obtained within the application.

[0349] Furthermore, the location information of the communication content may be acquired by executing an application for acquiring only the program information from the communication transmission path.

[0350] Furthermore, information indicating whether the online content is available for acquisition and information indicating whether the online content is available for playback may be acquired by an API or the like.

[0351] Furthermore, the information on the start time of acquiring the communication content is not limited to the control code of the AIT, but may be written in the control information, or may be determined based on the presence or absence of other control information.

[0352] [Modification of the third embodiment] The functions (operations) described in the third embodiment may be implemented in software or hardware. Alternatively, some of the functions may be implemented as APIs, allowing the functions to be controlled from an application. Alternatively, an API may be implemented that can acquire information obtained by the functions and information indicating the status of the functions, allowing the information to be acquired from the application.

[0353] Here, the functional status refers to, for example, the occupied capacity of a buffer (delay buffer, de-jitter buffer), end-to-end delay time, application status, and communication content acquisition status.

[0354] If it is determined that the program being played is not an on-air program but a recorded program, the receiving device may obtain information on whether the application or communication content is valid from the server. If the application or communication content is invalid, the receiving device may prohibit the acquisition and execution of the application or the acquisition of the communication content.

[0355] In such cases, application control information for recording and playback, pre-acquisition information for communication content for recording and playback, etc. may be prepared separately on the server, and in the case of recording and playback, information for on-air broadcasting may not be used, and information for recording and playback may be acquired from the server.

[0356] In addition, in the above-mentioned third embodiment, an example has been described in which content acquisition is mainly performed based on the start time of the acquisition of the communication content. However, the completion time of the acquisition of the communication content may be specified, and the receiving device may determine the start time of the acquisition of the communication content taking into account the time required for communication transmission and transmission delays. Furthermore, when application control or communication content acquisition is performed through a linked terminal such as a tablet, the time required for the acquisition of the communication content may be determined taking into account transmission delays between the linked terminals.

[0357] (Supplementary note to the third embodiment) [Supplement 1: Acquisition of communication content] The acquisition of communication content described with reference to FIGS. 19 and 20 will now be described in further detail.

[0358] In a broadcasting and communication cooperation service, information necessary for determining each control method for delay control, synchronization control, and communication content acquisition control includes control information signaled from the transmitting side, the state of the receiving device, and the state of the transmission path. The receiving device can acquire this information as needed. In addition, the receiving device can detect changes in the information and state by monitoring the following information and state.

[0359] The flow relating to the acquisition of information and status corresponds to steps S201 to S204 in Fig. 19. Examples of control information, status of the receiving device, and status of the transmission path include the following.

[0360] (1) The control information relating to the broadcasting and communication cooperation includes, for example, the following information (for example, stored in a metafile such as PMT in the MPEG-2TS system or MPT in the MMT system): -Information indicating whether it is a broadcasting and communications collaboration program - Information indicating the type of broadcasting and communications collaboration program Information indicating that the content is scalably coded and that one of the base layer data and the enhancement layer data is broadcast and the other is transmitted via communication - Information indicating that the program has been subjected to rain attenuation countermeasures (when rain attenuation deteriorates the broadcast transmission path, the content is switched to instead). Other information indicating multi-view, multi-audio, or targeted advertising -Information indicating whether the broadcast program can be decoded independently Information indicating the accuracy of synchronization required for decoding and presenting broadcast content and communication content. This information indicates, for example, whether high-precision synchronization at the frame level is required, or whether asynchronous presentation is possible. Information indicating whether broadcast content and communication content are to be synchronized -Information on whether the timeline is synchronized -Information indicating whether the video is live or not Information indicating that broadcast content is delayed relative to communication content, or communication content is delayed relative to broadcast content. Note that this information may not be the delay of an individual receiving device, but may be information indicating the amount of delay expected based on the line design of the broadcasting station. Information indicating the acceptable end-to-end delay in the presentation of broadcast programs - Information that notifies you in advance that control information will change

[0361] (2) Examples of information related to communication means include the following information: Note that information related to communication means is stored in, for example, an MPD in MPEG-DASH or a metafile in the IPTVF VOD specification. - Information indicating the communication protocol (e.g., http, rtsp, etc.) Information indicating whether it is unicast (TCP), multicast (UDP), or unicast (UDP)

[0362] (3) Examples of information related to communication content include the following information: Note that information related to communication content is stored in, for example, an MPD in MPEG-DASH or a metafile in the IPTVF VOD specification. Information indicating the attributes of communication content Content expiration date Content viewing restrictions (CAS) Content type (resolution, transmission rate) -Can communication content be obtained in advance at any time?

[0363] (4) The following parameters are exemplified as the state of the broadcast transmission path, the state of the communication transmission path, and the state of the delay. Note that these parameters are acquired by the receiving device. - Communication channel status Jitter, QoS, RTT End-to-End Delay Transmission rate (bandwidth) - Delay difference between broadcast and communication (broadcast first? communication first?)

[0364] (5) The buffer status may be exemplified by the following parameters, which are acquired by the receiving device: Buffer capacity Buffer occupancy Buffer delay

[0365] (6) The specifications or capabilities of the receiving device include the following parameters, which are acquired by the receiving device: Specifications Number of decoders Supported browsers Version information, etc.

[0366] (7) Information relating to delay control, synchronization control, and content acquisition control methods is exemplified by "information indicating whether to issue a control instruction." This information is stored in a metafile such as a PMT in the MPEG-2TS format or an MPT in the MMT format.

[0367] The information indicating whether to issue a control instruction specifies, for example, whether the broadcasting station issues an instruction on the control method, whether the receiving device determines the control method, or whether the user determines the control method through user settings.

[0368] When the broadcast station instructs the control method, the broadcast station instructs, for example, whether to synchronously present the broadcast content and the communication content, or whether to pre-buffer the communication content. When instructing pre-buffering, the broadcast station signals time information and timing information.

[0369] When the user determines the control method through user settings, the user settings include settings that follow instructions from the broadcasting station, settings that are left to the receiver, and manual settings by the user.

[0370] [Supplement 2: Determining whether communication content can be obtained at any time] So far, we have explained the cases where the communication content can be acquired at any time and the cases where it cannot. Here, the receiving device may determine whether the communication content can be acquired at any time and determine the control content based on the determination result.

[0371] Whether or not communication content can be acquired at any time can be determined, for example, by control information signaled from the transmitting side.

[0372] 1.Depends on communication method This determination can be made based on whether the communication method in the broadcast / communication cooperation service is unicast or multicast. For example, in the case of multicast, it is determined that the communication content cannot be acquired at any time.

[0373] 2. Content Dependence Whether or not communication content among broadcasting and communication cooperative content can be acquired at any time is signaled, and a determination can be made based on the signaled information. Based on the signaled information, the determination is made, for example, as follows. 2-1. Communication content cannot be obtained at any time 2-2. All communication content is stored on the server and can be retrieved at any time. 2-3. It is unclear whether communication content can be obtained at any time (for example, in the case of live video).

[0374] In the above cases 1, 2-1, and 2-2, the receiving device can determine the control content by analyzing the control information signaled on the transmitting side, so that the control content can basically be determined without making an inquiry to the server. Even in these cases, if the determination by analyzing the control information is impossible, the control content is determined by making an inquiry to the server. Figure 23 is a flowchart showing an example of determining whether communication content can be acquired at any time.

[0375] 23, the receiving device first analyzes the control information transmitted from the server and determines whether the communication content can be acquired at any time (step S401). If the determination is possible by analyzing the control information (S402: Yes), the control content is determined based on the determination result (step S404). If the determination is not possible by analyzing the control information (S402: No), the receiving device makes a determination based on an inquiry to the server (step S403), and the control content is determined based on the determination result (step S404).

[0376] If it is determined that it is impossible to acquire the communication content at any time, the receiving device performs buffer control, for example, using the methods described in embodiments 1 and 2, to control the delay and synchronous presentation between the broadcast content and the communication content.

[0377] If it is determined that the communication content can be acquired at any time, the method described in embodiment 3 is used, for example, to control the buffer of the receiving device and the acquisition of the communication content, thereby controlling the delay between the broadcast content and the communication content, or presenting the broadcast content and the communication content synchronously.

[0378] Specifically, when it is determined as 2-3 above, the server signals whether the broadcast content is live video and determines that it is live video.

[0379] Here, if the broadcast content is live video, it is highly likely that the communication content is not prepared on the server, but there are cases where the content is prepared on the server, so whether it can actually be acquired is determined by the receiving device making an inquiry to the server.

[0380] The server may also signal whether the broadcast is a delayed live video. If the broadcast is a live video that is not delayed, it is highly likely that the communication content is not prepared on the server, whereas if the broadcast is delayed, it is likely that the communication content is prepared on the server. In this case, the server may signal information about how much the broadcast is delayed.

[0381] The time it takes for the receiving device to actually acquire the communication content depends on the bandwidth of each communication line, the capabilities of the receiving device, CPU usage, buffer size, etc. Therefore, in the case of 2-3 above, the sending side (server) may signal whether the communication content can be acquired at any time in the environment assumed by the sending side, and may guarantee acquisition of the communication content by the receiving side.

[0382] Here, the environment assumed by the transmitting side is an environment determined based on, for example, the minimum buffer size defined by the standard, the bandwidth of the communication line, and the CPU capacity.

[0383] The above describes the determination of whether or not online content can be acquired at any time. However, it may also be determined whether or not online content can be acquired at any time for broadcast content. For example, in the case of live video, the period during which it can be acquired may be limited, such as whether or not online content can be acquired a predetermined time after the broadcast content.

[0384] [Supplement 3: Behavior when delayed presentation of broadcast content is not permitted] Below, we will explain the operation when communication content can be acquired at any time, and when there is a possibility that communication content can be acquired at any time but delayed presentation of broadcast content is not permitted (prohibited).

[0385] In the broadcasting and communication cooperation service, the delayed presentation of the main broadcast content creates a sense of incongruity for the viewer and results in a unstable broadcasting service. Therefore, this paper describes control under the condition that the delayed presentation of the broadcast content in the broadcasting and communication cooperation service must not be allowed.

[0386] As mentioned above, whether or not the communication content can be acquired at any time may be determined based on the control information or by actually making an inquiry to the server. In the following explanation, it is assumed that the communication content to be synchronized with the broadcast content changes over time (there are multiple communication contents at each time).

[0387] FIG. 24 is a flowchart showing an example of the operation when delayed presentation of broadcast content is not permitted.

[0388] First, the receiving device acquires the delay time between the communication content and the broadcast content (step S451). The delay time (delay difference) between the broadcast content and the communication content can be acquired by the receiving device as described above. Then, the receiving device determines whether the communication content is delayed relative to the broadcast content (step S452).

[0389] If the communication content is delayed relative to the broadcast content (S452: Yes), the broadcast content cannot be delayed, so the receiving device acquires the communication content at a later time (step S453). In other words, the receiving device skips frames of the communication content.

[0390] Here, the receiving device determines whether or not the communication content of the desired time can be acquired (step S457). If the communication content of the desired time can be acquired (S457: Yes), that is, if the communication content of the desired time is communication content even if it is for a later time, the receiving device acquires the communication content of the later time and synchronously presents the broadcast content and the acquired communication content (step S459).

[0391] If the communication content cannot be acquired at the desired time (S457: No), synchronous presentation is not possible. Therefore, the receiving device determines whether the accuracy of decoding and presenting the broadcast content and communication content is acceptable, and if not, presents only the broadcast content (step S458).

[0392] If the accuracy of decoding and presentation is acceptable, the decoding and presentation of the broadcast content and the decoding and presentation of the communication content are controlled independently (step S458). For example, if the communication content is subtitles added to the broadcast content, it is considered that high-accuracy synchronization is not necessary, and therefore it may be acceptable to present the broadcast content and the communication content without synchronizing them.

[0393] Note that the case where the accuracy of decoding and presentation is acceptable specifically means that the time difference between the playback timing of the communication content and the playback timing of the broadcast content is within a predetermined tolerance range, and the case where the accuracy of decoding and presentation is unacceptable means that the time difference between the playback timing of the communication content and the playback timing of the broadcast content is outside the predetermined tolerance range.

[0394] On the other hand, if the broadcast content is delayed relative to the communication content (S452: No), the receiving device determines whether the delay buffer for the communication content has sufficient capacity (whether the remaining capacity is less than a predetermined value) (step S454).

[0395] If there is not enough buffer capacity (S454: No), the receiving device acquires communication content that is earlier in time than the communication content currently acquired (step S455). If communication content for the desired time can be acquired (S457: Yes), the receiving device acquires communication content for the desired time and synchronously presents the broadcast content and the acquired communication content (step S459). In this case, it is usually possible to acquire the desired communication content. If communication content for the desired time cannot be acquired, synchronous presentation is not possible, so the receiving device presents only the broadcast content, or independently controls the decoding and presentation of the broadcast content and the decoding and presentation of the communication content (step S458).

[0396] If there is a spare capacity in the buffer (S454: Yes), the communication content is buffered and delayed (step S456), and the presentation time is synchronized with the broadcast content, thereby presenting the broadcast content and the communication content in synchronization (step S459).

[0397] If the polarity of the delay time difference between the broadcast content and the communication content is reversed or there is a possibility that it will be reversed, the change in state is detected, and 1-1 and 1-2 are controlled based on the detection result.

[0398] 24, steps S454 and S456 may be omitted. That is, even if there is sufficient buffer capacity, the previous communication content may be acquired. In this case, if the broadcast content is delayed relative to the communication content (S452: No), the receiving device acquires the communication content earlier than the currently acquired communication content (step S455).

[0399] Next, a request to acquire communication content from the server of the receiving device, which is made in steps S453 and S455, will be described.

[0400] When acquiring the communication content from the server, the receiving device requests acquisition of the communication content by specifying the timing to acquire the communication content and the time (for example, PTS) of the communication content to be acquired.

[0401] If the server has communication content for the specified time, it transmits the communication content to the receiving device. If the server does not have communication content for the specified time, it notifies the receiving device that there is no communication content.

[0402] Here, if the receiving device does not have communication content for the specified time, the server may transmit communication content for the most recent time to the receiving device instead of the communication content for the specified time. Also, the server may transmit communication content for the time closest to (before or after) the specified communication content to the receiving device. Also, the above-mentioned notification and transmission of alternative communication content may be combined.

[0403] If the receiving device does not have the communication content for the specified time, the server may transmit the communication content to the receiving device based on an instruction from the receiving device.

[0404] Incidentally, when a receiving device requests acquisition of a communication content and specifies the requested communication content by a function, the time of the requested communication content and an operation instruction in the case where the content is not available are stored as arguments.

[0405] Here, the operation instruction does not necessarily have to be included in the acquisition request, and after the receiving device determines the operation to be performed when it is determined that synchronous presentation is not possible (step S458), the operation instruction for when communication content is not available may be given based on the determined operation.

[0406] Specifically, for example, if the accuracy of decoding and presenting the broadcast content and the communication content is acceptable, the receiving device issues an instruction to request acquisition of communication content at an alternative time, and decodes and presents the broadcast content and the communication content independently. Also, for example, if the accuracy of decoding and presenting the broadcast content and the communication content is unacceptable, the receiving device issues an instruction that communication content does not need to be transmitted, and presents only the broadcast content.

[0407] In addition, if there is no communication content at the time specified by the receiving device, or if there is no random access point at that time, the receiving device may request to obtain the communication content that is closest to the communication content at the specified time (either before or after the specified time).

[0408] Next, the presentation control of broadcast content and communication content performed in steps S458 and S459 will be described.

[0409] (1) Until the communication content is ready to be presented During the time until the communication content is ready for presentation, if accuracy is required in the decoding and presentation of the broadcast content and the communication content, the receiving device presents only the broadcast content. If accuracy is not required in the decoding and presentation of the broadcast content and the communication content, the receiving device decodes and presents the broadcast content and the communication content independently.

[0410] (2) After the communication content is ready to be presented In the above (1), if only the broadcast content is being presented (if the presentation of the network content has been stopped), the receiving device starts the synchronous presentation of the broadcast content and the network content.

[0411] On the other hand, in the above (1), if the broadcast content and the communication content are decoded and presented independently, and if the broadcast content is delayed, the communication content is skipped and the broadcast content and the communication content are presented synchronously. If the communication content is delayed and the communication content was presented in the above (1), the receiving device retroactively presents (or continues to present) the communication content that was presented in the above (1).

[0412] When presenting the content, a message indicating the status (for example, a message indicating whether the broadcast content and the communication content are being presented synchronously or whether the broadcast content is being presented independently) may be presented to the user.

[0413] In addition, when the communication content can be acquired before the broadcast content, the server may signal whether or not it is okay to present the communication content before the broadcast content. If it is okay to present the communication content first, the receiving device presents the communication content immediately after preparation for presentation of the communication content is completed. If it is not okay to present the communication content first, the receiving device buffers the communication content until preparation for presentation of the broadcast content is completed, and after preparation for presentation of the broadcast content is completed, presents the broadcast content and the communication content synchronously.

[0414] [Supplement 4: How to set the delay time on the sending side] This section explains how a transmitting station (transmitting device) sets the delay amount for broadcast content when delaying broadcast content. Broadcast content is transmitted from a transmitting station to multiple receiving devices, but the capabilities and communication bandwidth of each receiving device vary. For this reason, it is difficult to guarantee that all receiving terminals can receive the broadcast content with a delay.

[0415] Therefore, in order to change the delay amount depending on the receiving device, the transmitting station may be configured to be able to switch between multiple delay modes, where, for example, the transmitting station is provided with multiple delay modes with different expected communication transmission rates.

[0416] Specifically, the transmitting station is provided with a first mode that assumes a high transmission speed such as an optical line, and a second mode that assumes a medium transmission speed such as CATV or ADSL.

[0417] The amount of delay is determined based on the following formula, for example.

[0418] Delay amount = minimum buffer size specified by the standard / expected transmission speed in each mode

[0419] The transmitting station may signal the delay amount and delay mode in the broadcast signal. In this signaling, the delay amount and delay mode are stored in the PMT in MPEG-2 TS or the MPT in MMT. This allows the receiving device to control itself based on the signaled delay amount and delay mode.

[0420] In addition, if it is determined that the actual delay amount is larger than expected based on the signaled delay amount and the actual delay amount, the receiving device may increase the allocation of resources (CPU speed and communication transmission speed) of the receiving device to the communication.

[0421] Also, for example, if the receiving device cannot accommodate the signaled delay amount, only the broadcast content is presented with priority.

[0422] In addition, there may be cases where the same content, such as baseball or soccer, is simultaneously transmitted using both broadcast and communication cooperative content and regular broadcast-only content. In such cases, the transmitting station may delay-transmit the broadcast-only content together with the broadcast and communication cooperative content to be transmitted with a delay, or may transmit the content as is without a delay.

[0423] Furthermore, in simultaneous broadcasting, the transmitting station may signal information indicating whether each content has been transmitted with a delay, or whether there is a delay difference, and information on each delay difference.

[0424] [Supplement 5: Configuration of transmitter] Here, we will provide additional information about a transmitting device (specifically, a server) used in a transmitting station (broadcast station). Fig. 25 is a block diagram showing the configuration of a transmitting device. Fig. 26 is a flowchart showing an example of the operation of the transmitting device. Fig. 26 is a flowchart of the operation of the transmitting device corresponding to the flowchart in Fig. 19.

[0425] 25, the transmitting device 300 includes an encoding unit 301, a multiplexing unit 302, and a transmitting unit 303. The components of the transmitting device 300 are specifically realized by a microcomputer, a processor, a dedicated circuit, or the like.

[0426] The transmitting unit 303 transmits information for acquiring the online content to the receiving device (step S501), corresponding to step S203 in Fig. 19 described above. Here, an example of the information for acquiring the online content is the acquisition information described above. That is, the transmitting unit 303 transmits, via broadcasting, information related to the acquisition of the online content, which is information for playing the online content transmitted by communication in synchronization with the broadcast content transmitted by broadcasting.

[0427] Specifically, the multiplexing unit 302 packetizes the encoded acquired information output from the encoding unit 301, and the transmitting unit 303 transmits the acquired information packetized by the multiplexing unit 302 via broadcasting.

[0428] Next, the transmitting unit 303 transmits the broadcast content to the receiving device (step S502), which corresponds to step S206 in FIG. 19 described above.

[0429] Specifically, the multiplexing unit 302 packetizes the coded broadcast content output from the coding unit 301, and the transmitting unit 303 transmits the broadcast content packetized by the multiplexing unit 302 via broadcasting.

[0430] In this way, by transmitting the acquisition information, the receiving device can appropriately acquire the communication content in response to reception of the broadcast content. Furthermore, by the receiving device acquiring the communication content in response to the acquisition information, the possibility of discontinuities such as skipping or stopping occurring in the presentation of the broadcast, which is the main content, can be reduced, and stable broadcast viewing can be ensured.

[0431] (Summary of the third embodiment) A receiving method according to one aspect of the present invention is a receiving method in a broadcasting and communication collaboration service, which receives broadcast content transmitted by broadcasting, receives acquisition information via broadcasting, which is information related to the acquisition of the communication content, for playing the communication content transmitted by communication in synchronization with the received broadcast content, and acquires the communication content based on the received acquisition information.

[0432] Such a receiving method is shown in the flowchart of Fig. 19. According to such a receiving method, it is possible to appropriately acquire communication content in response to reception of broadcast content. Furthermore, by acquiring communication content in response to acquisition information, it is possible to reduce the possibility of discontinuities such as skipping or stopping occurring in the presentation of the broadcast, which is the main content, and to ensure stable broadcast viewing.

[0433] Typically, broadcast content and communication content constitute one content (content presented on one presentation unit). For example, if the broadcast content is video, the communication content is the subtitles displayed in response to the video shown by the broadcast content. In scalable coding, for example, each frame constituting a 60 fps video is the broadcast content, and each frame added to the broadcast content to form a 120 fps video is the communication content. In addition, there are cases where the broadcast content is the main video and the communication content is an advertisement (CM).

[0434] In other words, the above "synchronization" means adjusting the time difference between the playback timing of the broadcast content and the playback timing of the communication content to a predetermined time difference (a time difference within a predetermined range) in order to play a single content composed of the broadcast content and the communication content.

[0435] The acquisition information may be information indicating timing related to acquisition of the communication content.

[0436] In this way, the timing related to the acquisition of the communication content is specified by the transmitting side (server), thereby realizing a receiving method that can appropriately acquire the communication content in response to the reception of the broadcast content.

[0437] The acquisition information may also be information indicating a timing at which acquisition of the communication content should be started in order to play the communication content in synchronization with the received broadcast content.

[0438] The acquisition information may also be information indicating a timing at which acquisition of the communication content should be completed in order to play the communication content in synchronization with the received broadcast content.

[0439] The acquisition information may also be information indicating a timing at which the reproduction of the communication content should be started in order to reproduce the communication content in synchronization with the received broadcast content.

[0440] The acquisition information may be information indicating that the communication content will be available for acquisition from a timing notified.

[0441] As described above, various aspects of timing related to the acquisition of communication content are conceivable.

[0442] Furthermore, the timing to start acquiring the online content may be calculated based on the received acquisition information, and the acquisition of the online content may be started at the calculated timing.

[0443] Such a receiving method is shown in step S303 in the flowchart of Fig. 21. That is, if the content acquisition start time is not directly specified, the content acquisition start time may be calculated on the receiving side. Note that, in order to calculate the acquisition start time with higher accuracy, information described in the third embodiment, such as the capabilities of the receiving device, the state of the communication transmission path, and transmission delay, may also be used.

[0444] The acquisition information may be information indicating that the communication content is available for acquisition.

[0445] Furthermore, the acquired communication content may be reproduced in synchronization with the received broadcast content.

[0446] Furthermore, if the acquisition of the communication content fails, only the broadcast content may be reproduced out of the broadcast content and the communication content.

[0447] Such a receiving method is shown in step S255 in Fig. 20, step S308 in Fig. 21, and step S458 in Fig. 24. In this way, by only playing the broadcast content when synchronization cannot be achieved, a broadcasting and communication cooperation service that is less likely to cause discomfort to viewers is realized.

[0448] In addition, if the acquired communication content cannot be played back in synchronization with the received broadcast content, (1) if the time difference between the playback timing of the communication content and the playback timing of the broadcast content is within a predetermined tolerance range, the communication content and the broadcast content may be played back, and (2) if the time difference is outside the predetermined tolerance range, only the broadcast content of the broadcast content and the communication content may be played back.

[0449] Such a receiving method is shown in step S458 etc. in Fig. 24. In this way, within a permissible range, the broadcast content and the communication content may be played back without being synchronized.

[0450] Furthermore, a transmission method according to one aspect of the present invention is a transmission method in a broadcasting / communication collaboration service, in which acquisition information, which is information related to the acquisition of the communication content and is used to play communication content transmitted by communication in synchronization with broadcast content transmitted by broadcasting, is transmitted via broadcasting.

[0451] Such a transmission method is shown in the flowchart in Fig. 26. According to such a transmission method, the receiving side can appropriately acquire communication content in response to reception of broadcast content, reducing the possibility of discontinuities such as skipping or stopping occurring in the presentation of the broadcast, which is the main content, on the receiving side, and ensuring stable broadcast viewing.

[0452] In addition, a receiving device according to one embodiment of the present invention is a receiving device used in a broadcasting and communication collaboration service, and is equipped with a broadcast receiving unit that receives broadcast content transmitted by broadcasting and acquisition information via broadcast, which is information related to the acquisition of the communication content, and is used to play the communication content transmitted by communication in synchronization with the received broadcast content, and a communication unit that acquires the communication content based on the received acquisition information.

[0453] Here, the broadcast receiving unit corresponds to the digital broadcast receiving unit shown in Figures 1, 9, 10, and 14, etc., and the communication unit corresponds to the communication transmitting / receiving unit shown in Figures 1, 9, 10, and 14, etc.

[0454] In addition, a transmitting device according to one embodiment of the present invention is a transmitting device used in a broadcasting / communication collaboration service, and is equipped with a transmitting unit that transmits acquisition information via broadcasting, which is information for playing communication content transmitted by communication in synchronization with broadcast content transmitted by broadcasting, and is information related to the acquisition of the communication content.

[0455] Here, the transmitting unit corresponds to the transmitting unit shown in FIG.

[0456] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, etc. Furthermore, these comprehensive or specific aspects may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0457] (Other embodiments) Although the first to third embodiments have been described above, the present invention is not limited to the above embodiments.

[0458] For example, in the third embodiment, broadcast content is transmitted by broadcasting, and communication content is transmitted by communication, but other information (for example, control information) may be transmitted by either broadcasting or communication if possible.

[0459] In each of the above embodiments, each component may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may also be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0460] Each component may be a circuit. These circuits may form a single circuit as a whole, or each may be a separate circuit. Each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0461] For example, in each of the above embodiments, a process executed by a specific processing unit may be executed by another processing unit, the order of multiple processes may be changed, or multiple processes may be executed in parallel.

[0462] While the receiving device (receiving method) and transmitting device (transmitting method) according to one or more aspects have been described based on the embodiments, the present invention is not limited to these embodiments. As long as they do not deviate from the spirit of the present invention, various modifications conceivable by those skilled in the art to the present embodiments, or configurations constructed by combining components of different embodiments, may also be included within the scope of one or more aspects. [Industrial Applicability]

[0463] The receiving method of the present invention can be used in a broadcasting and communication cooperation service as a receiving method that can appropriately acquire communication content in response to reception of broadcast content. [Explanation of symbols]

[0464] 1, 1A, 1B, 100, 100A receiving device 3 Broadcast antenna 5, 5B presentation part 11, 111 Digital broadcast receiving unit 12, 112, 122 Separation section 13, 22 buffer 14, 14A, 14B Decoding section 21, 41, 121 Communication transmitter / receiver 23, 23B, 115, 125 Decoding section 31, 31A, 31B, 32B, 131 Content generation unit 42 Operation input section 51, 151 Control unit 71 PES buffer 72 Synchronization buffer 103, 113 Delay Buffer 114, 124 Separation buffer 123 De-jitter Buffer 141 Control Management Department 171 Control Information Extraction Unit 172 Buffer Management Unit 173 Monitoring Department 174 Control method determination unit 191, 196 Synchronous buffer 300 Transmitting device 301 Encoding section 302 Multiplexer 303 Transmission Unit

Claims

[Claim 1] Transmitting broadcast content via broadcast; transmitting, via the broadcast, acquisition information for linking communication content transmitted by communication with the received broadcast content, the acquisition information being information related to the acquisition of the communication content, location information indicating a storage location of the communication content, information indicating whether or not there is communication content linked with the broadcast content, and information indicating the type of the communication content; The acquisition information includes information indicating the expiration date of the communication content. Sending method.

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