Receiving method

Abstract

To enable quick access to content by communication when reproducing content using both broadcasting and communication on a receiving side. [Solution] The receiving method includes a receiving step of receiving content transmitted using both broadcast waves and a communication channel, and a playback step of playing the content when control information is received, the control information including information indicating that there is content transmitted via the communication channel and information for playing the content via the broadcast waves and the content via the communication channel, which information relates to the content transmitted via the communication channel. In the receiving step, the base layer of the content is received via the broadcast waves, and the extension layer is received via the communication channel. In the receiving step, information indicating which base layer asset corresponds to which extension layer asset is received via the communication channel. In the receiving step, information indicating the type of control information for the content transmitted via the communication channel is received via the broadcast waves.

Description

[Technical Field]

[0001] The present invention relates to a transmission method and a reception method. [Background technology]

[0002] Conventionally, the main transmission path for distributing content has been broadcast waves, and an example of a media transport method widely used in broadcasting systems using broadcast waves is MPEG-2 TS (Moving Picture Experts Group-2 Transport Stream).

[0003] Meanwhile, with the recent advances in network technology, it has become possible to distribute content using communication channels such as the Internet. In other words, content can now be distributed using not only broadcast waves but also communication channels, and the transmission channels over which content can be distributed are becoming more diverse.

[0004] For example, Non-Patent Document 1 discloses MMT (MPEG Media Transport) as a new media transport method that assumes content distribution using both broadcasting and communication (see Non-Patent Document 1). For example, Patent Document 1 discloses a technology that mainly uses broadcasting and accesses communication content based on data acquired from the broadcast. [Prior art documents] [Non-patent literature]

[0005] [Non-Patent Document 1] Information technology - High efficiency coding and media delivery in heterogeneous environment - Part1:MPEG media transport(MMT), ISO / IEC DIS 23008-1 Summary of the Invention [Problem to be solved by the invention]

[0006] However, although there has been discussion about obtaining information (service information) related to content reception and the like in order to distribute content using a combination of broadcasting and communications and receive distributed content, and then starting to receive content, no consideration has been given to quick access to content via communications, which leads to issues such as delays in the timing at which content reception via communications begins.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a content transmission method that enables quick access to content via communication when content that combines broadcasting and communication is reproduced on the receiving side. [Means for solving the problem]

[0008] In order to solve the above problem, a receiving method according to one aspect of the present invention includes a receiving step of receiving content transmitted using both broadcast waves and a communication path, and a playback step of playing the content when control information is received, the control information including information indicating the presence of the content transmitted via the communication path and information for playing the content via the broadcast waves and the content via the communication path, the control information including information regarding the content transmitted via the communication path, wherein in the receiving step, a base layer of the content is received using the broadcast waves and an extension layer is received using the communication path, in the receiving step, information indicating which asset of the extension layer corresponds to which asset of the base layer, in the receiving step, information indicating the type of control information of the content transmitted via the communication path is received using the broadcast waves, and in the receiving step, location information indicating the source of the content or information indicating the source of the location information is received.

[0009] These general or specific aspects may be realized by a data receiving method, an integrated circuit, a computer program, or a computer-readable recording medium such as a CD-ROM, or may be realized by any combination of a data transmitting method, a data receiving method, an integrated circuit, a computer program, and a recording medium. [Effects of the Invention]

[0010] According to the present invention, it is possible to realize a content transmission method and the like that enables quick access to content via communication when content that combines broadcasting and communication is played back on the receiving side. [Brief explanation of the drawings]

[0011] [Figure 1A] 3 is a diagram showing an example of a data structure of service information in the broadcast communication cooperative service of the first embodiment. FIG. [Figure 1B] 3 is a diagram showing an example of a data structure of service information in the broadcast communication cooperative service of the first embodiment. FIG. [Figure 2] FIG. 2 is a diagram showing an example of an outline of a transmission path identification descriptor according to the first embodiment. [Figure 3A] FIG. 10 is a diagram illustrating another example of the data structure of service information in the broadcasting and communication cooperative service according to the first embodiment. [Figure 3B] FIG. 10 is a diagram illustrating another example of the data structure of service information in the broadcasting and communication cooperative service according to the first embodiment. [Figure 4A] 10 is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to the first embodiment. [Figure 4B] 10 is a flowchart showing another example of the operation on the receiving side in the broadcast communication cooperative service according to the first embodiment. [Figure 5] FIG. 2 is a block diagram showing an example of the configuration of a receiving device according to the first embodiment. [Figure 6A] FIG. 10 is a diagram showing an example of a data structure of service information in a broadcast communication cooperative service according to a first modification of the first embodiment. [Figure 6B]FIG. 10 is a diagram showing an example of a data structure of service information in a broadcast communication cooperative service according to a first modification of the first embodiment. [Figure 7A] 10 is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to the first modification of the first embodiment. [Figure 7B] 10 is a flowchart showing another example of the operation on the receiving side in the broadcast communication cooperative service according to the first modification of the first embodiment. [Figure 8] FIG. 10 is a block diagram showing an example of the configuration of a receiving device according to a first modification of the first embodiment. [Figure 9] 10 is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to the second modification of the first embodiment. [Figure 10] FIG. 10 is a block diagram showing an example of the configuration of a receiving device according to a second modification of the first embodiment. [Figure 11A] FIG. 13 is a diagram showing an example of a data structure of application control information in a broadcasting and communication cooperative service according to a fourth modification of the first embodiment. [Figure 11B] FIG. 13 is a diagram showing an example of a data structure of application control information in a broadcasting and communication cooperative service according to a fourth modification of the first embodiment. [Figure 12] FIG. 13 is a diagram showing another example of the data structure of application control information in the broadcasting and communication cooperative service according to the fourth modification of the first embodiment. [Figure 13A] 13 is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to the fourth modification of the first embodiment. [Figure 13B] 13 is a flowchart showing a comparative example of the operation on the receiving side in the broadcast communication cooperative service according to the fourth modification of the first embodiment. [Figure 14] FIG. 10 is a diagram illustrating an example of a data structure of service information in the broadcasting and communication cooperative service according to Example 1 of Embodiment 2. [Figure 15] 10 is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to Example 1 of the second embodiment. [Figure 16A]FIG. 10 is a diagram illustrating an example of the syntax of a location information descriptor in Example 2 of Embodiment 2. [Figure 16B] FIG. 10 is a diagram illustrating an example of the syntax of a location information descriptor in Example 2 of Embodiment 2. [Figure 16C] FIG. 10 is a diagram illustrating an example of the syntax of a location information descriptor in Example 2 of Embodiment 2. [Figure 16D] FIG. 10 is a diagram illustrating an example of the syntax of a location information descriptor in Example 2 of Embodiment 2. [Figure 17] 13 is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to Example 3 of the second embodiment. [Figure 18] 13 is a flowchart showing another example of the operation on the receiving side in the broadcast communication cooperative service according to Example 3 of Embodiment 2. [Figure 19] 13 is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to Example 4 of the second embodiment. [Figure 20] FIG. 10 is a block diagram showing an example of the configuration of a receiving device according to Example 4 of Embodiment 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Findings that form the basis of the present invention) Currently, services that deliver content by combining broadcasting and communications (broadcast-communications integrated services) are being considered. Among these, a promising method is one that uses broadcasting as the primary medium and accesses content acquired via communications (hereafter referred to as communications content) based on data acquired from broadcasting. When receiving content in a broadcast-communications integrated service, it is expected that the receiver will begin receiving the content via coded audio and video data or a data carousel in an MPEG-2 system after acquiring service information, similar to conventional services that deliver content only via broadcasting.

[0013] However, the service information that can be acquired through conventional services does not take into consideration the operation of quickly accessing communication content, the operation of selectively receiving only broadcast content, etc. Therefore, when providing a broadcasting and communication integrated service using conventional service information, there are issues such as an increase in the amount of processing related to analyzing the service information and a delay in the timing of starting to acquire communication content.

[0014] Similarly, the hybrid cast standard, which was standardized by the IPTV Forum and has already been adopted by the ARIB standard, does not take into consideration operations such as quick access to communication content or operations when selecting and receiving only broadcast content.

[0015] In the conventional hybridcast specification, which was standardized by the IPTV Forum and has also been adopted as an ARIB standard, an HTML5 application is downloaded on the communication side and started when an event message is fired, etc. As a result, it does not support playback control of communication content based on the PTS (Presentation Time Stamp) or DTS (Decoding Time Stamp) in the audio and video frames on the broadcast side, and has issues such as being unable to support highly accurate synchronized playback, such as synchronizing the display times of broadcast content and communication content on a frame-by-frame basis.

[0016] In order to solve such problems, a transmission method according to one aspect of the present invention is a content transmission method capable of transmitting content using broadcast waves and a communication channel, and when transmitting content using both broadcast waves and a communication channel, includes an information transmission step of including information regarding the content to be transmitted via the communication channel in application control information, which information is used to synchronize the content via the broadcast waves with the content via the communication channel when received by the receiving side, and transmitting the information using at least the broadcast waves of the broadcast waves and the communication channel.

[0017] According to this aspect, it is possible to realize a content transmission method that enables rapid access to content via communication when content that combines broadcasting and communication is played back on the receiving side. More specifically, when content is transmitted using broadcast waves and a communication path, information for achieving synchronization between the content transmitted using the broadcast waves and the communication path is included in the application control information and transmitted, so that when the receiving side receives application control information including this information, the receiving side can quickly access the content via communication in accordance with this information, and the receiving side can achieve synchronization between the content.

[0018] Here, for example, in the information transmission step, the application control information may be transmitted prior to transmitting the content, and the application control information may further include location information indicating the source from which the content is obtained or information indicating the source from which the location information is obtained.

[0019] Furthermore, for example, in the information transmitting step, the application control information may be transmitted by including difference information between a reference clock of the content via the broadcast wave and a reference clock of the content via the communication path.

[0020] Also, for example, in the information transmission step, the application control information may be transmitted, thereby synchronizing the reference clock of the content via the communication path with the reference clock of the content via the broadcast wave based on the difference information, thereby allowing the receiving side to achieve the synchronization.

[0021] In addition, in order to solve the above problem, a receiving method according to one aspect of the present invention includes a receiving step of receiving content transmitted using both a broadcast wave and a communication channel, and a playback step of, when application control information for synchronizing the content transmitted via the broadcast wave and the content transmitted via the communication channel, which information includes information regarding the content transmitted via the communication channel, is received from at least the broadcast wave of the broadcast wave or the communication channel, performing the synchronization process and playing back the content.

[0022] Here, for example, in the receiving step, the application control information may be received prior to receiving the content, and if the application control information includes location information indicating the location from which the content is to be obtained, the content may be received by obtaining the content based on the location information.

[0023] Also, for example, in the receiving step, the application control information is received prior to receiving the content, and if the application control information includes information indicating the source of location information indicating the source of the content, the location information may be obtained based on the information indicating the source of the location information, and the content may be received by obtaining the content from the obtained location information.

[0024] Also, for example, in the playback step, the application control information including difference information between the reference clock of the content via the broadcast wave and the reference clock of the content via the communication path is received in the receiving step, and if the reference clock of the content via the broadcast wave and the reference clock of the content via the communication path are different, the content may be synchronized by synchronizing the reference clock of the content via the communication path with the reference clock of the content via the broadcast wave based on the difference information, and the content may be played back.

[0025] In addition, in order to solve the above problem, a transmitting device according to one embodiment of the present invention is a content transmitting device capable of transmitting content using broadcast waves and a communication path, and when transmitting content using both broadcast waves and a communication path, is equipped with an information transmitting unit that includes information regarding the content to be transmitted via the communication path in application control information, which information is used to synchronize the content transmitted via the broadcast waves with the content transmitted via the communication path when received by the receiving side, and transmits the information using at least the broadcast waves of the broadcast waves and the communication path.

[0026] In addition, in order to solve the above problem, a receiving device according to one embodiment of the present invention includes a receiving unit that receives content transmitted using both broadcast waves and a communication channel, and a playback unit that, when application control information is received that includes information for synchronizing the content transmitted via the broadcast waves and the content transmitted via the communication channel and information related to the content transmitted via the communication channel, performs the synchronization process and plays the content.

[0027] These general or specific aspects may be realized by a transmission method, a transmission device, a receiving method, a receiving device, an integrated circuit, a computer program, or a recording medium such as a computer-readable CD-ROM, or may be realized by any combination of a data reception method, an integrated circuit, a computer program, or a recording medium.

[0028] Hereinafter, a transmission method, a reception method, etc. according to one embodiment of the present invention will be specifically described with reference to the drawings.

[0029] It should be noted that the embodiments described below each illustrate a specific example of the present invention. The numerical values, shapes, materials, components, component placement and connection configurations, steps, and step order shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept are described as optional components.

[0030] (Embodiment 1) In this embodiment, a transmission method for transmitting and receiving content in a broadcasting and communication cooperation service will be described.

[0031] [How to send] In this embodiment, the transmitting side transmits content (data or assets) using broadcast waves and a communication path, but transmits service information prior to transmitting the content.

[0032] [Service Information] Here, service information refers to information for obtaining audio, video, or data related to data broadcasting after a channel selection operation (after channel selection), or a series of information related to receiving content or obtaining metadata, such as EPG (Electric Program Guide) information.

[0033] Currently, broadcasts are mainly transmitted using MPEG-2 TS (Transport Stream) sections, which include PAT (Program Association Table), PMT (Program Map Table), NIT (Network Information Table), CAT (Conditional Access Table), or EIT (Event Information Table) defined by ARIB (Association of Radio Industries and Businesses).

[0034] In this embodiment, MMT (MPEG Media Transport) standardized by MPEG will be used as an example of the multiplexing format on the broadcast side in the broadcast collaborative service. However, this multiplexing format is not limited to MMT, and other multiplexing formats such as TS and MPEG-DASH (Dynamic Adaptive Streaming over HTTP) may also be used.

[0035] Service information in this embodiment is transmitted in a data structure that can be stored in a multiplexing format. For example, in MMT, service information is transmitted using a table such as an MMT Package Table (MPT) or message information such as a Package Access (PA) message. In each table, auxiliary information can be described using a descriptor, just like in TS.

[0036] 1A and 1B are diagrams showing an example of the data structure of service information in the broadcasting and communication cooperative service of Embodiment 1. More specifically, Fig. 1A shows an MPT including a transmission path identification descriptor, and Fig. 1B shows an example in which, in the transmission path identification descriptor shown in Fig. 1A, information about the transmission path of assets constituting a package is described as attribute information.

[0037] (Attribute information) 1) The attribute information may include information indicating whether the assets constituting the package are transmitted by (1) broadcasting only or (2) a combination of broadcasting and communication.

[0038] The information may also indicate whether the audio and video data of the main program will be transmitted by (1) broadcasting only or (2) broadcasting and communication. This information allows audio, video, still images, or metadata separate from the main program, such as HTML files, to be acquired from the communication network even if the main program is transmitted by broadcasting only.

[0039] 2) When audio or video data is transmitted using both broadcasting and communication, information indicating the relationship between the data transmitted by each method may be included as attribute information.

[0040] Here, for example, when scalability (temporal resolution (e.g., 60 fps → 120 fps), spatial resolution (e.g., 4k → 8k), bit depth (e.g., 8 bit → 10 bit)) is to be realized, the attribute information can indicate that the base layer will be used for broadcasting and the enhancement layer will be used for communication. The attribute information may also indicate that the frame rate of broadcast data alone is 60 fps, but that the frame rate can be increased to 120 fps when communication data is used in combination. It may also indicate that backup data for broadcasting will be transmitted via communication. This allows the transmitting side to use the attribute information to switch to transmitting data via communication when the broadcast reception conditions deteriorate due to rain attenuation or the like.

[0041] The attribute information may also indicate information for identifying assets related to each other. For example, the attribute information may indicate an asset ID of a base layer and an asset ID of an enhancement layer corresponding to the base layer.

[0042] In MMT, it is also possible to transmit the same asset using multiple transmission paths. Therefore, the attribute information may indicate whether the same asset is transmitted using both broadcasting and communication. In this case, identification information of the asset (such as an asset ID) may be separately indicated. Information for identifying related assets may be indicated by an individual transmission path identification descriptor for each asset, as shown in FIG. 2, for example. Here, FIG. 2 is a diagram showing an example of an overview of a transmission path identification descriptor in the first embodiment. The individual transmission path identification descriptor shown in FIG. 2 may indicate, for example, information for identifying whether the asset is a base layer asset or an extension layer asset, or if the asset is an extension layer asset, may indicate the ID of the corresponding base layer asset.

[0043] The attribute information may also be used to group broadcast assets and communication assets, and to indicate a list of assets included in each group. If there are assets that are transmitted via both broadcast and communication, they may be grouped separately.

[0044] 3) Information indicating whether audio and video transmitted by broadcasting and audio and video transmitted by communication are played back in sync may be included as attribute information.

[0045] The attribute information may indicate each piece of information as an individual field, or may define information indicating the type of service so that the service can be identified by the type. The attribute information may also be written in a format different from that of the descriptor.

[0046] The transmission path identification descriptor may be stored in a table or message that indicates information on a package basis, which is different from the MPT. The contents of the transmission path identification descriptor may be written as a data structure different from that of the descriptor.

[0047] When transmitting a plurality of packages, a table or message showing a list of packages may be defined, and information such as a transmission path identification descriptor may be shown as package attribute information as information on a package unit basis.

[0048] 3A and 3B are diagrams showing another example of the data structure of the service information in the broadcasting and communication cooperative service according to the first embodiment.

[0049] That is, as shown in Figures 3A and 3B, the location information for each asset may be stored in separate MPTs for assets transmitted via broadcasting and communications. In this case, the attribute information for the package can be stored in the MPT sent on the transmission path that is the entry point for the service. For example, if broadcasting is the entry point, the package attribute information is stored in the MPT sent via broadcasting. These MPTs can be identified by table_id.

[0050] In the MMT standard, the value of the table_id of the reference MPT is specified as zero, so it is possible to set the table_id of the MPT corresponding to the entry point transmission path to zero, and the table_id of the MPT corresponding to the other transmission path to 1 or more.

[0051] The MPT of a broadcast asset may be transmitted by broadcasting, and the MPT of a communication asset may be transmitted by communication.

[0052] Furthermore, the location information of broadcasting and communication assets may be stored in a single MPT. In this case, the location information of each asset may be stored consecutively to facilitate easy identification. For example, if there are N1 broadcasting assets and N2 communication assets, the information of the N1 broadcasting assets is first described consecutively, followed by the information of the N2 communication assets. Note that the transmission path identification descriptor may indicate that N1 assets are transmitted via broadcasting and N2 assets are transmitted via communication.

[0053] In this way, the transmitting side transmits the service information including the transmission path identification descriptor as auxiliary information. As a result, the receiving side can obtain in advance, by simply acquiring the service information including the auxiliary information, whether communication data is included or the dependency relationship between broadcast data and communication data, based on the package attribute information described in the transmission path identification descriptor, without analyzing the information for each asset.

[0054] In particular, when receiving communication data, there is an advantage in that the delay time associated with starting the reception process can be reduced.

[0055] [Transmitting device] For example, the transmitting device of this embodiment is a content transmitting device that can transmit content using broadcast waves and communication paths, and generates package attribute information such as a transmission path identification descriptor as auxiliary information, and transmits it by including it in the service information.

[0056] The transmitting device of this embodiment may transmit this service information periodically. When the content of this service information is updated, the updated content is reflected in the service information immediately after the update.

[0057] Furthermore, the entry point is not limited to broadcasting, but may be communication, or entry may be possible from both broadcasting and communication. When entry is possible from both, package-based information is transmitted from at least both broadcasting and communication transmitting devices.

[0058] Note that when the receiving side receives content from the broadcasting and communication cooperation service, it is not necessary to receive data sent through both transmission paths. For example, it may receive and play only the broadcast data. In this case, since the information required when the receiving side receives the communication data is not required when receiving the broadcast data, the transmitting side may transmit the information required when receiving the communication data through communication. In other words, the transmitting side may transmit information in package units through a transmission path that serves as an entry point, and transmit information specific to the transmission path, such as broadcasting or communication, through each transmission path (for example, Figure 2). Note that the following description will be given assuming that broadcasting is the entry point.

[0059] In this way, service information specific to each transmission path can be generated and transmitted by the transmitting device of each transmission path. However, information transmitted by MPT, such as asset location information, can be transmitted by broadcasting, since the delay time associated with the start of asset acquisition on the communication side can be reduced by first acquiring it all at once.

[0060] (Examples of communication-specific information) Examples of information specific to communications (communications networks such as the Internet and CDNs (Content Delivery Networks)) are shown below.

[0061] 1) Information related to FEC (Forward Error Correction) in packets sent via communication, such as FEC method and parameters 2) Information related to QoS (Quality of Service) control, such as packet loss rate, packet arrival time jitter, RTT (Round Trip Time), and end-to-end delay in the communication transmission path. 3) Information about buffering, such as buffering time and amount, from when asset data is received until decoding begins

[0062] In broadcasting, FEC and QoS are important, especially for mobile broadcasting (such as one-segment broadcasting in Japan), but the parameters for these are different from those for communication paths. Therefore, information specific to broadcasting only needs to be transmitted during broadcasting.

[0063] On the other hand, in communications, it is possible to select multiple audio and video data according to the bandwidth of the communications network, such as bit rate and frame rate. At this time, information associating the attribute information (bit rate, etc.) of the selectable data with the asset ID may be transmitted. Note that such associating information may be transmitted via broadcasting.

[0064] The associated information may indicate whether or not there are multiple selectable assets, or if there are multiple selectable assets, may indicate a list of the selectable assets.

[0065] [Receiving method] In this embodiment, the receiving side starts receiving (acquiring) the content after acquiring the service information. The receiving method in this embodiment will be described below with reference to the drawings.

[0066] Fig. 4A is a flowchart showing an example of an operation on the receiving side in the broadcast communication cooperative service according to Embodiment 1. Fig. 4A shows an example of an operation in which the receiving device acquires the transmission path identification descriptor according to the present embodiment and determines an asset to be received.

[0067] First, the MPT table included in, for example, a PA message or an MPT message as service information transmitted on a transmission path that is an entry point is acquired, and the transmission path identification descriptor included therein is acquired.

[0068] Next, the information in the transmission path identification descriptor is interpreted, such as whether the asset is transmitted using both broadcasting and communication, and if both transmission paths are used, the dependency between the broadcasting and communication assets (step S101).

[0069] Messages such as PA messages are stored in the payload of packets such as MMT packets, and the type of data stored is indicated by the packet header. Therefore, when receiving an MMT package, the ID number in the packet header (corresponding to packet_id in an MMT packet) is first referenced to obtain the MMT packet of the PA message.

[0070] Next, the asset to be received is determined based on the playback capability of the terminal or whether a communication path is available (step S102).

[0071] Here, an example of a method for determining assets will be described.

[0072] 1) When the receiving device is not connected to a communication network, it determines to receive only broadcast assets, and does not receive assets transmitted via both broadcast and communication.

[0073] 2) When the base layer of a video is transmitted by broadcast and the enhancement layer is transmitted by communication, if only the base layer can be played back, it is determined to receive only the broadcast, and if both layers can be played back, it is determined to receive both the broadcast and communication. For example, assume that temporal scalability of 60 fps can be achieved with only the base layer and 120 fps with the base layer and enhancement layer. In this case, if the receiving device can only decode and display up to 60 fps, it will receive only the broadcast data, but if it can decode and display up to 120 fps, it will receive both the broadcast and communication data.

[0074] 3) A receivable asset is determined from multiple assets with different bit rates transmitted by communication according to the bandwidth of the communication network to which the receiving device is connected. Here, for example, information such as the bit rate of each asset is transmitted separately in service information, etc. Note that if the reception state is poor due to congestion in the communication network or the like and there are no assets that can be stably received, it may be determined not to receive data from the communication side.

[0075] 4) In addition, if backup data is transmitted in communication in preparation for a deterioration in the broadcast reception environment, the asset to be acquired may be determined when the reception environment deteriorates. In this case, the receiving device may monitor the reception environment, determine whether to receive the communication asset based on an index such as an error rate in the received data, and perform reception processing.

[0076] 5) When receiving data (such as video enhancement layer data) via communication that is played back in synchronization with the audio and video data of the main program transmitted by broadcast, special operations such as buffering the data before playback begins may be required to ensure synchronization between the data received via broadcast and the data received via communication. In this case, only assets that do not require strict synchronization (for example, frame-by-frame synchronization) with the data transmitted via broadcast may be received via communication. For example, assets such as HTML data, still images, and videos that do not require strict synchronization may be determined to be acquired via communication.

[0077] Returning to the flowchart of FIG. 4A, the following description will be given.

[0078] Next, in step S103, it is decided (determined) whether or not to receive the asset transmitted by communication, and if it is decided (determined) to receive it (Yes in S103), proceed to S104, and if it is decided (determined) not to receive it (No in S103), proceed to S105.

[0079] In S104, assets are received from both the broadcast and communication transmission paths, and in S105, assets are received only from the broadcast.

[0080] FIG. 4B is a flowchart showing another example of the operation on the receiving side in the broadcast communication cooperative service according to the first embodiment.

[0081] 4A, in FIG. 4B, when service information specific to a communication is transmitted in the communication, a step of receiving the service information (step S106) is added. The rest is the same as that explained in FIG. 4A, so the explanation will be omitted.

[0082] If there is service information specific to the broadcast, it is assumed that it is received separately in a step not shown.

[0083] Furthermore, if the receiving device does not support the broadcast and communication integrated service, it may receive only broadcast assets. In this case, if there is an asset transmitted via both broadcast and communication, the asset will not be received.

[0084] [Receiver] Fig. 5 is a block diagram showing an example of the configuration of a receiving device according to Embodiment 1. Fig. 5 shows an example of the configuration of a receiving device that realizes the receiving method described in Fig. 4A.

[0085] The receiving device 100 shown in FIG. 5 includes an identification information acquiring unit 101, an asset determining unit 102, a determining unit 103, a broadcast receiving unit 104, and a communication receiving unit 105.

[0086] The identification information acquisition unit 101 has a function to realize step S101 shown in Fig. 4A. Specifically, the identification information acquisition unit 101 acquires service information transmitted on a transmission path that is an entry point, and acquires a transmission path identification descriptor (auxiliary information) included therein. Then, the identification information acquisition unit 101 interprets the information of the transmission path identification descriptor.

[0087] The asset determination unit 102 has a function for implementing step S102 shown in FIG. 4A, and determines the asset to be received based on the playback capabilities of the terminal or whether a communication path is available.

[0088] The determination unit 103 has a function to realize step S103 shown in Fig. 4A, and determines (determines) whether to receive an asset transmitted by communication. Specifically, the determination unit 103 determines whether to receive communication data, and if it determines to receive it, the broadcast receiving unit 104 and the communication receiving unit 105 receive the asset data determined in step 102.

[0089] If the determination unit 103 determines that communication data is not to be received, it receives the data using only the broadcast receiving unit 14 .

[0090] (Variation 1) In this modification, an example will be described in which broadcasting is performed using TS, and communication is performed using DASH, RTP (Real-time Transport Protocol), or the like.

[0091] 6A and 6B are diagrams showing an example of the data structure of service information in a broadcasting and communication cooperative service according to Modification 1 of Embodiment 1. Fig. 6A shows an example in which information about data transmitted in communication is stored in a PMT. Fig. 6B shows an example of the data structure of a transmission path identification descriptor according to this modification.

[0092] In this modification, a transmission path identification descriptor indicating the attribute information and the like described in FIGS. 1A and 1B is stored in a PMT, which is an example of service information.

[0093] In the program information in the TS such as the PMT, only the location information of the data transmitted by the TS is indicated. Therefore, in this modification, when content data is transmitted using communication in addition, the location information of the data on the communication side is stored in the transmission path identification descriptor. More specifically, the attribute information includes flag information indicating whether communication is also used. This allows the transmitting side to select whether to include the location information of the data on the communication side depending on the value of the flag information. Note that the location information is not limited to being stored in the transmission path identification descriptor. A separate descriptor may be defined to store the location information.

[0094] (Location information) Location information is information that indicates the source of data, and corresponds to a PID in the case of TS, a URL or URI in the case of communication, etc.

[0095] As the location information, a Media Presentation Description (MPD) of DASH, a Session Description Protocol (SDP) of RTP, or the like may be stored.

[0096] Furthermore, the location information is not limited to storing entity data of location information such as MPD or SDP, but may also store information indicating a source from which the entity data of the location information is to be acquired. Here, the information indicating a source from which the entity data of the location information is to be acquired is, for example, information indicating a URL for acquiring an MPD. However, when information indicating a source from which the entity data of the location information is to be acquired is stored in the location information, a delay occurs due to the need to separately acquire the entity data of the location information. Therefore, from the viewpoint of reducing the delay until the communication side starts receiving data, it is desirable to directly store the entity data in the location information.

[0097] Note that the DASH MPD is large in size because it contains various information related to the source of content. Therefore, instead of storing the MPD as is in the location information, it is also possible to store subset information that includes only the URL of the source of content and information related to the DTS and PTS of the segment.

[0098] It is also desirable to be able to handle updates to the content of location information such as MPD.

[0099] For example, a version number may be assigned to the location information. This allows the location information to be reacquired when the version number is updated. Note that to confirm whether the version number has been updated, information such as the transmission path identification descriptor in the periodically transmitted PMT may be checked sequentially. However, since this sequential check process is heavy, section data for storing location information, etc. may be generated separately (called a transmission path identification section) and transmitted periodically.

[0100] The receiving device can determine whether the location information has been updated by checking the version number in the transmission path identification section. Note that attribute information and location information may be transmitted in both the program information such as the PMT and the transmission path identification section. Alternatively, only location information may be stored in the transmission path identification section.

[0101] Furthermore, after starting to acquire data on the communication side based on location information acquired from broadcasting, updated content of the location information may be acquired through communication. At this time, since the source of the location information is required, the source of the location information may be stored together with the entity data of the location information in a broadcast transmission path identification descriptor or the like.

[0102] The receiving device can obtain updated information through communication by periodically accessing the source of the location information.

[0103] Furthermore, if a mechanism for exchanging messages exists between a DASH content distribution server and a receiving device, the server may issue a message to the receiving device indicating that the location information has been updated, and the receiving device may then reacquire the location information upon receiving the message.

[0104] Although the information about data transmitted in communication is stored in the PMT in the above description, this is not limitative. Attribute information and location information may be transmitted in a section different from the PMT.

[0105] Furthermore, the method of acquiring data on the communication side may be switched based on whether the data transmitted in communication is played back in synchronization with the audio and video in the broadcast.

[0106] For example, in the case of synchronous playback, the data on the communication side can be accessed from the broadcast program information as described above. In the case of non-synchronous playback, information for accessing the data on the communication side can be transmitted by data broadcasting using, for example, an AIT (Application Information Table) defined in the ARIB (Association of Radio Industries and Businesses) hybrid cast specifications. The receiving device receives the AIT in the form of a table or carousel, and acquires the data on the communication side based on the contents of the AIT. Playback of the acquired data on the communication side begins when an event message transmitted by data broadcasting is received.

[0107] Information such as AIT may also be used when broadcast data and communication data are played back synchronously. In this case, the start and end times of playback of the communication data are separately indicated in the data broadcast. The receiving device plays back the communication data according to these times.

[0108] The MPD in DASH and the SDP in RTP can indicate the playback start time or decoding start time of content, and these times are specified based on a reference clock, such as UTC (Coordinated Universal Time), specified for each multiplexing and transmission method. The Presentation Time Stamp (PTS) and Decoding Time Stamp (DTS) of individual video frames and audio samples are also set based on the reference clock. In broadcasting, on the other hand, the Program Clock Reference (PCR) serves as the reference clock, and therefore, when synchronously playing back broadcast data and communication data, information indicating the correspondence between their respective reference clocks is required.

[0109] Therefore, information indicating the correspondence between the reference clocks of the broadcasting data and the communication data may be included in the program information such as the PMT for broadcasting. For example, the information may indicate that the time when the PCR value in broadcasting is N1 and the time when the UTC value in communication is N2 correspond to the same time. Note that this information may be included in the MPD, SDP, etc.

[0110] The transmission path identification descriptor may also indicate transport layer protocol information, such as whether the data on the communication side is transmitted by UDP (User Datagram Protocol) or TCP (Transmission Control Protocol), which enables the receiving device to open ports used in each protocol or determine whether the protocol being used is supported.

[0111] Furthermore, identification information of the multiplexing format of the data on the communication side may be indicated so that it is possible to identify, for example, whether it is DASH or RTP.

[0112] [Receiving method] Below, with reference to the drawings, an example of the operation of a receiving device in this modified example, where broadcasting is transmitted using TS and communication is transmitted using DASH or RTP (Real-time Transport Protocol), will be described.

[0113] 7A is a flowchart showing an example of the operation of the receiving side in the broadcast communication cooperative service according to Modification 1 of Embodiment 1. FIG. 7A shows an example of the operation of the receiving device when attribute information and location information are stored in broadcast program information.

[0114] The operation of each step (step S201 to step S205) is the same as in the flowchart of Fig. 4A, but the difference is that in Fig. 4A, the data on the broadcasting side and the communication side is unified as an asset of the MMT package, whereas in Fig. 7A, the broadcasting side is TS data and the communication side is DASH or RTP data. As other points are as explained in Fig. 4A, detailed explanation will be omitted.

[0115] Fig. 7B is a flowchart showing another example of the operation of the receiving side in the broadcast communication cooperative service according to Variation 1 of Embodiment 1. Fig. 7B shows an example of the operation when attribute information and access information for acquiring location information are stored in the broadcast program information, but the actual location information is not stored.

[0116] Step S301 is similar to step S201, and therefore a description thereof will be omitted.

[0117] Next, in step S302, it is determined (judged) whether or not to receive data from the communication side, and in step S303, if data from the communication side is to be received, the process proceeds to S304, and if data from the communication side is not to be received, the process proceeds to S306.

[0118] In step S304, location information is acquired in accordance with the acquisition source of the location information of the communication side data included in the broadcast program information.

[0119] On the other hand, in step S305, communication side data is acquired based on the location information acquired in step S304, and broadcast data is also acquired, and in step S306, only data transmitted by broadcast is acquired.

[0120] (Attribute information) The attribute information is the same as that described in embodiment 1, but since embodiment 1 used MMT as an example, the following describes an example where TS is used for broadcasting and DASH or RTP is used for communication.

[0121] 1) The attribute information may include information indicating whether the data such as audio and video that make up the content will be transmitted using either (1) broadcasting only or (2) a combination of broadcasting and communication.

[0122] The information may also indicate whether the audio and video data will be transmitted using either (1) broadcasting only or (2) a combination of broadcasting and communication. This information allows the audio, video, still images, or metadata such as HTML files to be acquired from a communication network separate from that of the main content, even if the main content is transmitted using broadcasting only.

[0123] 2) When audio or video is transmitted using both broadcasting and communication, information indicating the relationship between the data transmitted by each method may be included as attribute information.

[0124] Here, for example, when realizing scalability (temporal resolution (e.g., 60 fps → 120 fps), spatial resolution (e.g., 4k → 8k), bit depth (e.g., 8 bit → 10 bit)), the attribute information can indicate that broadcasting will use the base layer and communication will use the enhancement layer. The attribute information may indicate a use case in which the frame rate of broadcast data alone is 60 fps, but the frame rate can be increased to 120 fps when communication data is used in combination. The attribute information may also indicate that backup data for broadcasting will be transmitted via communication. This allows the transmitting side to use the attribute information to switch to transmitting data via communication when the broadcast reception conditions deteriorate due to rain attenuation or the like.

[0125] The attribute information may also indicate information for identifying related coded streams. For example, the attribute information may indicate a PID of a TS packet storing basic layer data transmitted by broadcasting, a segment in DASH data transmitted by communication, or video data identification information such as a track ID in MP4.

[0126] The attribute information may also indicate information indicating broadcast data and communication data that are played back in sync with each other, allowing the transmitting side to transmit multi-viewpoint video or parent and child screen video in a picture-in-picture format via broadcast and communication, respectively.

[0127] 3) Information indicating whether audio or video transmitted by broadcasting and audio or video transmitted by communication are played back in sync may be included as attribute information.

[0128] 4) Information indicating whether the clock information of audio or video transmitted by broadcasting is the same as the clock information of audio or video transmitted by communication may be included as attribute information.

[0129] 5) Information indicating whether the data on the communication side is live content may be included as attribute information.

[0130] For example, if the content to be transmitted is not live content, data after the current time (T1) can be acquired. Therefore, by starting reception from data whose playback time is the time (T2) obtained by adding the total time (△T) required from the content acquisition request to the start of reception (or an estimate thereof) and the time required to buffer the data to the current time, the broadcast data can be played back without delay. At this time, the communication data is played back from time T2. On the other hand, if the content to be transmitted is live content, the broadcast data may be buffered for △T, and playback of both the broadcast and communication data may begin at time T2.

[0131] If the communication side multicasts or broadcasts the content using RTP or the like, data after the current time cannot be acquired regardless of whether the content is live or not. Therefore, information indicating whether the data on the communication side is multicast or broadcast may also be included in the attribute information.

[0132] [Receiver] Next, an example of the configuration of a receiving device when broadcasting is transmitted using TS and communication is transmitted using DASH, RTP (Real-time Transport Protocol), or the like will be described.

[0133] Fig. 8 is a block diagram showing an example of the configuration of a receiving device according to Modification 1 of Embodiment 1. Fig. 8 shows an example of the configuration of a receiving device that realizes the receiving method described in Fig. 7B.

[0134] Receiving device 300 shown in Fig. 8 includes identification information acquisition unit 301, decision unit 302, communication combined use determination unit 303, Loc information acquisition unit 304, broadcast receiving unit 305, and communication receiving unit 306. The configuration of the receiving device that realizes the receiving method of Fig. 7A corresponds to the case in Fig. 8 where Loc information acquisition unit 304 is not present.

[0135] The identification information acquisition unit 301 has a function to realize step S301 shown in Fig. 7B. Specifically, the identification information acquisition unit 301 acquires service information transmitted on a transmission path that is an entry point, and acquires a transmission path identification descriptor (auxiliary information) included therein. Then, the identification information acquisition unit 301 interprets the information of the transmission path identification descriptor.

[0136] The determination unit 302 has a function for implementing step S302 shown in FIG. 7B, and determines the data to be received based on the playback capability of the terminal or whether a communication path is available.

[0137] The communication joint use determining unit 303 has a function to realize step S303 shown in FIG. 7B, and determines (determines) whether or not to receive data transmitted by communication.

[0138] Loc information acquisition unit 304 has a function for implementing step S304 shown in FIG. 7B, and acquires location data of communication side data.

[0139] (Variation 2) In this modification, an example of a receiving method will be described in which attribute information and location information are stored in broadcast program information and transmitted.

[0140] [Receiving method] Fig. 9 is a flowchart showing an example of the operation of the receiving side in the broadcast communication cooperative service according to Modification 2 of Embodiment 1. Fig. 9 shows an example of the operation from when attribute information and location information are stored in broadcast program information and transmitted, until when the receiving device determines whether to synchronously play back broadcast content and communication content, and plays them back.

[0141] The operation of FIG. 9 is based on the operation of FIG. 7A, but is described as an example in which the transmission data is not an MMT asset but is more general content.

[0142] First, program information transmitted on a transmission path serving as an entry point is acquired, and a transmission path identification descriptor contained therein is acquired, and attribute information of the content and location information of the communication content are acquired (step S401).

[0143] Here, if the entity of the location information is not stored in the program information, the entity data of the location information is obtained in the same manner as described in FIG. 7B.

[0144] Next, the data to be received is determined based on the reproduction capability of the receiving device or whether a communication path is available (step S402).

[0145] Next, it is determined whether to acquire the communication content (step S403), and if it is determined to acquire the communication content (Yes in S403), the process proceeds to step S404, where data is received from both the broadcast and communication transmission paths. If it is determined (determined) not to receive the content (No in S403), the process proceeds to step S409, where data is received only from the broadcast, and only the broadcast content is played back in step S410.

[0146] Next, it is determined whether or not the broadcast content and the communication content are to be played back in synchronization with each other (step S405).

[0147] If it is determined that synchronous playback is to be performed (Yes in S405), the reference clocks of the broadcast content and the communication content are synchronized in step S406, and both are played back in synchronization in step S407.

[0148] The synchronization of the reference clocks in S406 may be performed prior to S404. This is because, for example, when playback is started after pre-buffering received content data, decoding and playback may be started after confirming that data with a PTS of T1 in the broadcast content and data with a PTS of T1 in the communication content (assuming that the PTSs of both are already synchronized) have been received, and when determining whether the data to be played back in synchronization with each other are available, it is necessary that the reference clocks of both are synchronized.

[0149] Furthermore, in synchronizing the reference clock in S406, it is possible to align it with the reference clock used in either broadcasting or communication. For example, if PCR (Program Clock Reference) is used in broadcasting and NTP (Network Time Protocol) is used in communication, the reference clocks for broadcasting and communication can be synchronized by converting the NTP-based DTS and PTS for video and audio to the PCR-based DTS and PTS. Furthermore, the DTS and PTS for broadcasting and communication may be converted so as to synchronize with a specific clock used in the receiving device.

[0150] In Figure 9, we have explained the operation when attribute information and location information are stored in the broadcast program information and transmitted, but if there is no need for synchronous playback in the first place, the transmission path identification descriptor describing this information may not be stored in the broadcast program information.

[0151] Furthermore, the reference clock can be synchronized to match the clock used in either broadcasting or communications. For example, if PCR (Program Clock Reference) is used in broadcasting and NTP (Network Time Protocol) is used in communications, the reference clocks for broadcasting and communications can be synchronized by converting the NTP-based DTS and PTS for video and audio to the PCR-based DTS and PTS. The DTS and PTS for broadcasting and communications may also be converted so as to synchronize with a specific clock used in the receiving device.

[0152] [Receiver] 10 is a block diagram showing an example of the configuration of a receiving device according to Modification 2 of Embodiment 1. In FIG. 10, an example of the configuration of a receiving device that realizes the receiving method described in FIG.

[0153] The receiving device 400 shown in Figure 10 includes an identification information acquisition unit 401, a determination unit 402, a communication use determination unit 403, a Loc information acquisition unit 404, a broadcast receiving unit 405, a communication receiving unit 406, a synchronization determination unit 407, and a playback unit 408.

[0154] The identification information acquisition unit 401 to the communication reception unit 406 are the same as the identification information acquisition unit 301 to the communication reception unit 306 described in FIG. 8, and therefore a description thereof will be omitted.

[0155] The synchronization determination unit 407 has a function of performing the process of step S405 shown in FIG.

[0156] The playback unit 408 decodes and plays back the broadcast content or the communication content based on the playback method determined by the results of the determination made by the communication concurrent use determination unit 403 and the synchronization determination unit 407 means.

[0157] (Variation 3) Below, other examples that are different from those described above will be described.

[0158] [Other 1] The transmission path is not limited to a combination of broadcast and communication, but may be a combination of the same type of transmission path, such as broadcast and broadcast, or communication and communication.

[0159] In addition, if package-based information such as a transmission path identification descriptor is not indicated, it may be possible to determine whether each asset is transmitted by broadcast or communication, or whether there are any assets in the package that are transmitted by communication, by interpreting the location information for each asset such as that shown in Figures 1A and 1B.

[0160] (Location information) The location information may include URL information of the asset acquisition destination. If the acquisition destination is a URL, it is possible to determine whether the asset will be transmitted by broadcast or communication based on whether the URL is a specific URL predefined in the broadcast service.

[0161] For example, when a broadcast asset is transmitted in the same stream as message information such as MPT, the location information indicates the ID of the packet that stores the asset data (packet_id in the case of an MMT packet) as the source of the broadcast asset, and for an asset transmitted via communication, a URL is indicated as the source. Therefore, whether an asset is transmitted via communication may be determined depending on whether the source of the asset is a URL in the location information.

[0162] (MPT description variation) 1A and 1B, the information for each asset is defined as location information for each asset and an individual transmission path identification descriptor, but this is not limited to this. A separate field indicating the encoding method of the asset may be provided. The encoding method is essential information for decoding, and it is desirable to signal it using information that can be obtained prior to decoding, such as MPT. For example, information such as stream_type in the MPEG-2 system can be used.

[0163] Furthermore, if the encoding method is capable of scalable encoding, it may also be indicated whether the asset is a base layer or an enhancement layer, along with the encoding method.

[0164] In addition, there may be cases where multiple scalable assets are included in the same MMT package, such as when there are two videos with temporal scalability. In such cases, information indicating which base layer asset corresponds to which enhancement layer asset may be indicated. For example, the asset ID of the corresponding base layer asset may be indicated for an enhancement layer asset. Furthermore, enhancement layer and base layer assets may be grouped, and a group ID may be assigned to each asset.

[0165] This information can be indicated in the program information for broadcasting, even when broadcasting uses TS and communication uses DASH, RTP, etc. For example, a PMT descriptor or the like can describe the dependency between the video stream transmitted by broadcasting and the video stream transmitted by communication (e.g., the video stream on the communication side corresponds to an extension layer), or information indicating the video and audio encoding method on the communication side. It may also indicate whether the stream on the broadcast side and the stream on the communication side are played back in sync.

[0166] (Information about transmission paths) Information indicating whether content data is transmitted only by broadcasting or transmitted by both broadcasting and communication may be stored in program information such as EPG.

[0167] For example, when selecting viewing or scheduling a recording from the EPG, if the data transmitted via communication cannot be played back or recorded because the device is not connected to a communication network or the receiving device does not support obtaining data via communication, a message indicating this may be displayed.

[0168] Furthermore, information indicating whether the data transmitted by communication can be acquired before the program start time may be stored. In particular, in a download-type system such as DASH, by downloading the data on the communication side before the program starts, it is possible to start playing both the broadcast data and the communication data at the program start time.

[0169] For example, if the data on the communication side can be acquired prior to the program start time, the receiving device may start receiving the data on the communication side before the program start time. In this case, the reception start time is determined so that a predetermined amount of buffered data or a predetermined amount of data for a buffering time can be received at the program start time.

[0170] Moreover, the same operation may be performed in the case of, for example, scheduled recording of a program.

[0171] In broadcasting and the like, a user can select multiple programs at any time, and even if communication data for the next program on the channel currently being viewed is received in advance, if the viewed program is switched, there is no benefit to receiving the communication data in advance. Therefore, at any viewing time, the communication side data for all programs that can be viewed after the viewing time and whose data is transmitted using both broadcast and communication may be buffered in advance. If it is not possible to receive data for all programs, the user may select and receive programs within the receivable range.

[0172] Furthermore, information indicating whether the broadcast data and the communication data are to be played back synchronously may be included in the program information such as EPG, and if synchronous playback is to be performed, the communication data may be buffered in advance. If synchronous playback is not to be performed, reception of the communication data may begin after reception of the broadcast data has begun.

[0173] Even if such information is not included in the EPG, similar information can be obtained by analyzing the MPT in MMT or the PMT when using TS for broadcasting, and a similar message can be displayed.

[0174] Furthermore, this information may be stored in control information used when demodulating a signal transmitted over a transmission path, such as a TMCC signal in the Japanese broadcasting system (ISDB-T).

[0175] This makes it possible to determine whether reception is necessary during communication at the time of demodulation, thereby speeding up the startup of the communication side.

[0176] (format) Note that HTTP-based file formats are not limited to DASH, but can also be HTTP Live Streaming (HLS) or Microsoft Smooth Streaming (MSS), and these methods also have content management information equivalent to MPD, so the relationship between the data on the broadcast side and the data on the communication side can be shown using a mechanism similar to DASH.

[0177] On the communication side, a TS stream may be used, or a format in which a 4-byte timestamp field is added to the beginning of the TS packet may be used. TS with a timestamp is used in many standards, including BD (Blu-ray (registered trademark) Disc) and the IPTV Forum.

[0178] [Other 2] (attribute information and location information) In the attribute information and location information, attributes of the entire content and attributes of individual streams such as audio and video may be stored separately.

[0179] For example, when DASH is used on the communication side, attribute information of the entire content, such as whether broadcast content and communication content are played back in sync, or whether the broadcast content is the base layer of scalability and the communication content is the extended layer, may be stored in a transmission path identification descriptor, etc. On the other hand, individual attributes for each stream, such as information for identifying video and audio that are the targets of synchronous playback, may be stored in the MPD.

[0180] As an example of attributes for each stream, when video in broadcasting is associated with audio of secondary audio transmitted in communication, the MPD may associate the PID of the TS packet storing the video with information for identifying an audio track or segment in DASH data, or an Adaptation Set or Representation, such as an audio track ID. Here, the identification information for the media on the broadcasting side may include, in addition to the PID, the ID of the transport stream including the TS packet of the PID, a service ID, etc.

[0181] The contents of the MPD may be updated, and the update information is managed by the DASH content distribution server. Therefore, by describing the individual attributes of the stream in the MPD, it is possible to achieve both the advantage of reducing the amount of information exchanged between the broadcast content transmission device and the communication content transmission server, and the advantage of being able to quickly start the communication content reception start process by storing the overall attributes in information acquired at the start of broadcast reception, such as the PMT.

[0182] In addition, both the overall attributes and the individual attributes may be described in either a descriptor such as a PMT in broadcasting or an MPD, or may be described in both. For example, in broadcasting, they may be described in a descriptor of application control information such as an AIT.

[0183] (Attribute information) Furthermore, the attribute information may include a method for synchronizing clock information of streams transmitted over different transmission paths, such as broadcasting and communication. In this case, the receiving device may perform clock synchronization based on this information.

[0184] For example, information for identifying the following three methods may be described as attribute information.

[0185] Method 1) The streams to be synchronized are based on a common clock, and there is no need to synchronize their clocks.

[0186] Method 2) Synchronization is performed based on clock synchronization information that is transmitted separately from the stream, such as a descriptor in the PMT.

[0187] Method 3) Synchronization is performed by referencing an independent stream that contains information for clock synchronization, such as the TS timeline extension (13818-1:2013 / AMD6 (2nd WD)) currently being standardized by MPEG.

[0188] In Method 3, the attribute information may include the PID of the TS packet that stores the stream for clock synchronization.

[0189] (Variation 4) As a new service that combines broadcasting and communications, there is the hybrid cast standard, which has been standardized by the IPTV Forum and has also been adopted as an ARIB standard.

[0190] The conventional hybridcast specification, which was standardized by the IPTV Forum and has also been adopted as an ARIB standard, enables linkage between broadcasting services and communication services based on application control information (AIT: Application Information Table).

[0191] However, with the conventional Hybridcast specification, an HTML5 application is downloaded on the communication side and started when an event message is fired, etc. Therefore, the conventional Hybridcast specification does not support playback control of communication content based on the PTS (Presentation Time Stamp) or DTS (Decoding Time Stamp) in the audio and video frames on the broadcast side, and is not able to support highly accurate synchronized playback, such as synchronizing the display times of broadcast content and communication content on a frame-by-frame basis.

[0192] In this modification, a mechanism for synchronizing and reproducing broadcast content and communication content with high accuracy will be described by extending the conventional hybrid cast specification.

[0193] The following describes the extension of application control information that enables highly accurate synchronized playback, and then describes the transmission method, playback method, etc. in this modified example.

[0194] Execution Mode The application control information of this modification introduces new information indicating the execution mode when an application is executed. There are two execution modes: Mode 1 and Mode 2. Examples of the execution modes are shown below.

[0195] (Mode 1) Mode 1 is an execution mode that does not require high-precision synchronization with other content.

[0196] In addition, in Mode 1, like applications of the conventional Hybridcast standard, startup or state transition is performed by control codes such as AUTOSTART, PRESENT, and PREFETCH, or by event messages. In Mode 1, synchronized playback by referencing the PTS or DTS of other audio or video streams is not required.

[0197] For example, an application example based on the conventional hybridcast standard is VOD (Video On Demand). When this VOD application is launched, a UI with a play start button and other controls is displayed. When the user presses the play start button, the content begins downloading or streaming and playback.

[0198] (Mode 2) Mode 2 is an execution mode that requires highly accurate synchronization with content transmitted via a transmission path other than broadcast waves.

[0199] In Mode 2, for example, video in a broadcast and audio acquired by an application are played back in synchronization with each other's PTS. Furthermore, when video scalability is applied, for example, the base layer data transmitted by broadcast and the enhancement layer data acquired by an application are decoded and displayed using DTS and PTS that are synchronized with each other. Here, the audio, video, and other streams that are played back in synchronization with each other are acquired by referencing the attribute information of the content described above.

[0200] (Application behavior in Mode 2) The application determines how to play the content on the communication side based on the execution mode. Since the operation in mode 1 is the same as in the past, a description thereof will be omitted. Below, the operation of the application in mode 2 will be described.

[0201] The basic operation when broadcast content and communication content are synchronously played back is as shown in the flowchart of FIG.

[0202] After clock synchronization, if the communication content is simply decoded and played back in accordance with the DTS or PTS converted to the synchronized clock, the communication content can be processed independently of the playback processing of the broadcast content.

[0203] On the other hand, when spatial scalability is applied to video and the base layer is transmitted via broadcasting and the enhancement layer is transmitted via communication, the enhancement layer is decoded using the decoding result of the base layer, so it is necessary to control the decoding processes of the broadcast content and the communication content in an integrated manner. Furthermore, when the broadcast content and the communication content are pre-buffered before playback is started, or when the reception buffer of either content overflows or underflows during playback, it is also necessary to control the playback processes of both transmission paths in an integrated manner. For example, processing is performed such as stopping reception of data on the overflowed side, or, when underflow occurs, stopping playback processing of both the broadcast content and the communication content until data of a predetermined length of time or a predetermined data size can be received.

[0204] Here, when integrated control is performed on at least one of the processes from reception to decoding and playback on both transmission paths, control commands are exchanged between the application on the communication side and the playback processing unit of the broadcast content. For example, the system operates using the following control commands:

[0205] 1) Decoding process related: For example, this is operated by a control command that requests and acquires data of an access unit corresponding to a specific DTS or PTS. Note that an access unit synchronized with broadcasting and communication may be acquired only at the start of playback, and thereafter a control command may be used to request and acquire data of the access unit immediately following in ascending order of DTS or PTS.

[0206] 2) Data reception related: This is operated by a control command that instructs the stopping and restarting of data reception, or that notifies that a data amount that meets a predetermined condition has accumulated in the pre-buffering buffer. Note that when data reception is stopped and restarted, subsequent processing such as decoding and playback may also be stopped and restarted, or a control command for a specific subsequent processing may be specified separately.

[0207] In addition, when an application operates in Mode 2, there are two main ways to deal with overflow or underflow of the pre-buffering buffer: waiting until data is available on both transmission paths before playing, or playing only the path for which data is available and skipping the path for which data is not available.

[0208] Therefore, in addition to specifying the playback mode, it may be possible to specify information indicating how to deal with overflow or underflow of the pre-buffering buffer.

[0209] For example, in broadcasting, there is no congestion on the transmission path and no underflows due to congestion occur, so broadcast content is played back according to the DTS and PTS of the access unit.If the communication content buffer underflows due to congestion on the communication path, playback of the access unit of the communication content for which no data exists in the DTS is skipped.

[0210] Here, when DASH is used as the communication content, when the buffer underflows, playback can be started quickly by skipping some segments instead of acquiring all of the subsequent segments.

[0211] More specifically, suppose that the DASH segments are SEG1, SEG2, SEG3, ... in ascending order of DTS, and the DTS of the first access unit of the segments is T1, T2, T3, .... In this case, if an underflow occurs during reception of SEG1, skipping reception of SEG2 and receiving SEG3 increases the likelihood that the data of the first access unit of SEG3 will be received at time T3, and as a result, decoding and playback of both broadcast and communication content can begin from time T3. When SEG2 is received, there is a high likelihood that the underflow state will continue, so skipping the received segment is expected to allow playback to resume quickly.

[0212] Also, for example, if an underflow occurs on the communication side, playback of the broadcast content is stopped until buffering of the communication content data is completed and playback becomes possible.

[0213] In addition, if the attribute information of the content transmitted by the broadcast PMT or the like indicates that the communication content is to be played back in synchronization with the broadcast content, or if the location information of the communication content can be identified as a specific file such as a DASH MPD based on the extension of the location information, the execution mode may be determined without explicitly describing the execution mode as control information.

[0214] Furthermore, when content transmitted over multiple transmission paths is played back in synchronization, the entire process from reception of broadcast and communication to playback may be controlled by a single application.

[0215] [Application Control Information] Next, an example will be described in which, in the hybrid cast specification, when broadcast content and communication content are synchronously played back, information relating to data transmitted in communication is stored in application control information.

[0216] 6A and 6B show an example in which location information of data on the communication side is stored in a transmission path identification descriptor and then stored in a PMT. In this modification, an example in which a transmission path identification descriptor is stored in application control information will be described.

[0217] In the conventional Hybridcast specification, the transmission path identification descriptor is not stored in the application control information, and location information must be acquired after the application is executed, resulting in delays.In contrast, by storing the transmission path identification descriptor in the application control information and describing (placing) location information in the transmission path identification descriptor, content acquisition can begin more quickly.

[0218] Here, the application control information is, for example, an AIT (Application Information Table), and is information that controls the startup and termination of an application as well as resources and access. For example, the application control information describes an application ID that identifies the application, a control code that can control the life cycle of the application, such as startup and termination, and application location information. Furthermore, the application control information is specified in section format and XML format, and there are two transmission methods: transmission in section format and transmission of XML format application control information using a data carousel. When transmitting application control information, a data encoding method descriptor including ait_identifier_info() is placed in the ES loop of the PMT.

[0219] 11A and 11B are diagrams showing an example of a data structure of application control information in a broadcasting and communication cooperative service according to Modification 4 of Embodiment 1. Specifically, Fig. 11A and 11B show an example in which information related to data transmitted in communication is stored in application control information in a section format.

[0220] In this modification, a transmission path identification descriptor is also stored in the descriptor for each application to indicate the attribute information and the like described in Figures 1A and 1B. For example, program information in a TS such as a PMT indicates only the location information of the data transmitted by the TS, so when content data is transmitted using communication in combination, location information of the data on the communication side is stored in the transmission path identification descriptor. More specifically, the attribute information may include flag information indicating whether communication is also used, and whether or not to include location information of the data on the communication side is selected depending on the value of the flag information.

[0221] Here, location information is information indicating where to obtain data, and corresponds to a PID for a TS section, a URL or URI for communications, etc. Location information can store MPD (Media Presentation Description) for DASH, SDP (Session Description Protocol) for RTP, etc.

[0222] Note that a separate descriptor may be defined to store the location information. Also, instead of storing the entity data of the location information, such as MPD or SDP, information indicating the source of the entity data may be provided.

[0223] For example, it is possible to indicate a URL for acquiring the MPD. However, since a delay occurs due to separately acquiring the entity data of the location information, it is desirable to store the entity data directly in order to reduce the delay until the communication side starts receiving data. However, since the DASH MPD contains various information related to the source from which the content is acquired, the size of the MPD is large. Therefore, instead of storing the MPD as is, it is also possible to store subset information including only the URL from which the content is acquired and information related to the DTS and PTS of the segment.

[0224] In this modification, as shown in FIGS. 11A and 11B, an example has been described in which the transmission path identification descriptor is stored in a loop for each application, but the present invention is not limited to this.

[0225] For example, when one transmission path identification descriptor is shared by multiple applications, the transmission path identification descriptor is stored in the loop of at least one of the applications that use the transmission path identification descriptor. In this case, the remaining application loops can be omitted by indicating information that can reference the transmission path identification descriptor. The information that can reference the transmission path identification descriptor is, for example, the loop number of the application in which the transmission path identification descriptor is stored or the application ID.

[0226] Alternatively, a transmission path identification descriptor may be stored in a loop (number of loops N) immediately below the application control information, an identifier that can identify the transmission path identification descriptor may be assigned, and the identifier to be referenced in each application may be referenced.

[0227] Furthermore, the case where the entity of the location information is stored in the transmission path identification descriptor is not limited to the above example.

[0228] For example, if the size of the location information entity is large, the transmission path identification descriptor including the location information entity or the application information including the transmission path identification descriptor may be described in a loop (here, loop N1) after the application information not including the location information entity. This makes it possible to acquire data other than the location information entity data first. Furthermore, a receiving device that does not need to acquire the location information entity data may complete acquisition of the application control information without acquiring the location information entity data to the end.

[0229] Alternatively, information indicating the source of the location information entity may be indicated within the application. In this case, instead of indicating the source of the location information entity, information that can identify the application whose source is indicated (for example, an application ID or an application URL) may be indicated, or the source of the location information entity may not be indicated.

[0230] 12 is a diagram showing another example of the data structure of application control information in the broadcasting and communication cooperative service according to Modification 4 of Embodiment 1. That is, in this modification, as shown in FIG. 12, information indicating that the application information identifier includes a transmission identification descriptor and attribute information may be stored in a descriptor such as ait_identifier_info() stored in the PMT. By analyzing the PMT, the receiver can more quickly determine that the content is broadcasting and communication cooperative content, thereby reducing the time required for synchronized playback of broadcast and communication.

[0231] Also, only the attribute information of the transmission path identification descriptor may be transmitted in the PMT.

[0232] Also, for example, an identifier such as application type may indicate that the application is an HTML5 application that operates in conjunction with broadcasting.

[0233] In this modification, the application control information is described using the section format, but the present invention is not limited to this. The transmission path identification descriptor may be stored in the application control information in XML format. In this case, the transmission path identification descriptor may be expressed in either the section format or the XML format.

[0234] Furthermore, in this modification, a different section may be defined without using application control information to achieve the same function. In this case, the PMT may store information (such as a PID or stream type) for identifying the section containing the transmission path identification descriptor. It is desirable to be able to handle updates to the content of location information such as the MPD. For example, the version number of the application control information may indicate that the MPD has been updated, or a control code in the application control information may be used to indicate that the MPD has been updated when the control code is indicated as MPD_CHANGE, or when the MPD is acquired via communication, the control code may be set as MPD_REROAD to cause the application to re-acquire it.

[0235] In this modification, attribute information and location information may be transmitted in both program information such as a PMT and a transmission path identification descriptor. In this case, only location information may be stored in the transmission path identification descriptor.

[0236] In this modification, after starting to acquire data on the communication side based on location information acquired from broadcasting, updated content of the location information may be acquired through communication. At this time, since the source of the location information is required, the source of the location information may be stored together with the entity data of the location information in a broadcast transmission path identification descriptor or the like. The receiving device can acquire the updated content through communication by periodically accessing the source of the location information. If a mechanism such as message exchange exists between the DASH content distribution server and the receiving device, the server may issue a message to the receiving device indicating that the location information has been updated, and the receiving device may re-acquire the location information upon receiving the message.

[0237] In this modification, information indicating the correspondence between the reference clocks of the broadcasting data and the communication data, as explained in FIGS. 6A and 6B, may be included in the transmission path identification descriptor or application control information.

[0238] In this modification, the transmission path identification descriptor may indicate transport layer protocol information, such as whether data on the communication side is transmitted by UDP (User Datagram Protocol) or TCP (Transmission Control Protocol). This enables the receiving device to open a port used in each protocol or determine whether the protocol being used is supported. Furthermore, identification information of the multiplexing format of the data on the communication side may be indicated, so that it is possible to identify, for example, whether it is DASH or RTP. This makes it possible to determine that the location information is described in the MPD format if the multiplexing format is DASH, for example.

[0239] [How to send] In this embodiment, the transmitting side transmits content (data or assets) using broadcast waves and a communication path, but transmits application control information prior to transmitting the content.

[0240] [Receiving method] In this embodiment, the receiving side starts receiving (acquiring) content after acquiring application control information. Below, a receiving method in this modified example will be described with reference to the drawings. That is, an example of the operation of a receiving device when broadcasting and communication are linked using the hybrid cast specification will be described. In this modified example, a case will be described in which broadcasting is transmitted using TS and communication is transmitted using DASH or RTP (Real-time Transport Protocol) or the like.

[0241] Fig. 13A is a flowchart showing an example of the operation of the receiving side in the broadcast communication cooperative service according to Variation 4 of Embodiment 1. Fig. 13A shows an example of the operation when attribute information and location information are stored in the broadcast application control information. It should be noted that the assets shown in Fig. 13A are TS data on the broadcast side and DASH or RTP data on the communication side. The attribute information is the same as that described in Fig. 7A.

[0242] First, in step S501, application control information is acquired. Next, the operations following step S502 are performed, but the operations from step S502 onwards (step S502, steps S504 to S506) are the same as the operations described in Fig. 7A (step S201, steps S203 to S205), so their description will be omitted. Only step S503, which performs a different operation, will be described below.

[0243] In step S503, it is determined whether to receive data transmitted via communication based on the information in the transmission path identification descriptor, and it is also determined whether to receive an application transmitted via communication based on the location information of the application described in the application control information.

[0244] Fig. 13B is a flowchart showing a comparative example of the operation on the receiving side in the broadcast communication cooperative service of Variation 4 of Embodiment 1. Fig. 13B shows an example of the operation when attribute information and access information for acquiring location information are stored in the broadcast program information, but the actual location information is not stored.

[0245] In step S601, application control information is acquired. Next, the operations following step S602 are performed. However, the operations from step S602 onwards (step S602, steps S604 to S607) are the same as the operations described in Figure 7B (step S301, steps S303 to S305), so their description will be omitted.

[0246] In step S603, it is determined whether to receive data transmitted via communication based on the information in the transmission path identification descriptor, and it is also determined whether to receive an application transmitted via communication based on the location information of the application described in the application control information.

[0247] It should be noted that the operation flow shown in Fig. 13A does not include a step of acquiring location information on the communication side, as compared to the operation flow shown in Fig. 13B. As a result, the operation on the receiving side shown in Fig. 13A can quickly acquire the start of communication data reception.

[0248] In addition, in the operation flow shown in Fig. 13A, processing equivalent to step S405, step S406, and step S407 described in Fig. 9 may be performed. That is, it is determined whether the broadcast content and the communication content are synchronously played back, and if synchronous playback is to be performed, synchronization information may be obtained from the transmission path identification descriptor, and the reference clocks for broadcasting and communication may be synchronized to perform synchronous playback.

[0249] Furthermore, at step S503 or step S603, preparations for starting an application may be made at the time when it is determined that data transmitted by communication will be received.

[0250] For example, the time it takes for an application to be executed can be reduced by launching an HTML5 browser as soon as it determines that data transmitted via communication has been received.

[0251] Furthermore, in step S603, if it is determined that the communication side's location information is to be transmitted by communication, an application may be immediately launched to acquire the communication side's location information. Furthermore, after acquiring the communication side's location information, buffering of the communication content may be started. The start timing of buffering may be indicated by a control command in the application control information, or pre-buffering time information may be described in the communication side's location information, which may be analyzed by the receiving device and pre-buffered.

[0252] Note that an application specified by application control information may be acquired from broadcast or communication as an application for acquiring location information on the communication side or an application for acquiring communication content, and executed. Furthermore, the application for acquiring location information on the communication side or the application for acquiring communication content may be implemented as a resident application. For example, a control command in the application control information may instruct control of the execution of an HTML5 application or a resident application, data acquisition, etc., or the execution of an HTML5 application or a resident application, data acquisition, etc. may be controlled at the discretion of the receiving device.

[0253] Furthermore, if the location information describes information about the capabilities of the receiving device required to play the content, the receiving device acquires the playback capabilities of the receiving device using an API command. In this case, the application that analyzes the location information is granted permission to acquire the playback capabilities of the receiving device. For example, if, after acquiring the communication-side location information in step S605, it is determined that the receiving device cannot play the content, the process may proceed to step S607, where only data transmitted by broadcasting may be received.

[0254] Additionally, API commands may be used to control the storage of communication side location information and communication content information acquired by various methods in the memory of the receiving device, the acquisition of information from memory, and the transfer of information between applications. An application can acquire part or all of the communication side location information by executing API commands. For example, location information acquired by a resident application can be set in the memory of the receiving device by API commands, and then retrieved from the memory by an HTML5 application by API commands.

[0255] [Effects of the First Embodiment] As described above, according to this embodiment, identification information indicating whether content including audio and video is transmitted by broadcasting and communication in combination, and information indicating the dependency between data transmitted over both transmission paths when broadcasting and communication are used in combination, may be generated and transmitted as content management information. Here, for example, the information indicating the dependency between data may include whether the data transmitted over both transmission paths are synchronously reproduced. Furthermore, the information indicating the dependency between data may include whether the clock information of the data transmitted over both transmission paths is the same.

[0256] This allows the transmission path over which content including audio and video is transmitted, and the dependencies between data transmitted over different transmission paths, to be obtained at the start of content reception, thereby reducing delays in determining the assets to receive and in starting to receive communication content.

[0257] Furthermore, according to this embodiment, location information of data transmitted in communication may be included in content management information. Here, the location information of the data to be transmitted may be, for example, an MPD in MPEG-DASH. Furthermore, the content management information may store information indicating a source of location information, rather than actual data of location information such as an MPD.

[0258] This allows the transmission path over which content including audio and video is transmitted, and the dependencies between data transmitted over different transmission paths, to be obtained at the start of content reception, thereby reducing delays in determining the assets to receive and in starting to receive communication content.

[0259] According to this embodiment, the receiving device may analyze the management information of the content to determine the transmission path for receiving the content and the data to be received on each transmission path. When data transmitted on both transmission paths is to be synchronously played back, auxiliary information required for clock synchronization between the data may be obtained, and the DTS and PTS in each data may be synchronized, decoded, and played back.

[0260] As a result, in a receiving device that receives only broadcast data, it is possible to reproduce broadcast data in the same manner as in conventional broadcast reception, while also being able to handle reproduction of communication data.

[0261] Furthermore, a mechanism can be provided for receiving devices to play back broadcast and communication data in synchronization.

[0262] Furthermore, as described above, according to this embodiment, it is possible to realize a content transmission method, reception method, transmission device, and reception device that enable quick access to content via communication when content that combines broadcasting and communication is played back on the receiving side.

[0263] Here, for example, a transmission method in one aspect of this embodiment is a content transmission method capable of transmitting content using broadcast waves and a communication path, and when transmitting content using both broadcast waves and a communication path, includes an information transmission step of including information regarding the content to be transmitted via the communication path in application control information, which information is used to synchronize the content via the broadcast waves with the content via the communication path when received by the receiving side, and transmitting the information using at least the broadcast waves of the broadcast waves and the communication path.

[0264] As a result, when content is transmitted using broadcast waves and a communication path, information for synchronizing the content transmitted by the broadcast waves with the content transmitted by the communication path when received by the receiving side is included in the application control information and transmitted, so that when the receiving side receives the application control information, the receiving side can quickly access the content transmitted by communication in accordance with this information, and the contents can be synchronized.

[0265] Also, for example, in the information transmission step, the application control information may be transmitted prior to transmitting the content, and the application control information may further include location information indicating the source from which the content is obtained or information indicating the source from which the location information is obtained.

[0266] Furthermore, a receiving method in one aspect of this embodiment includes a receiving step of receiving content transmitted using both a broadcast wave and a communication path, and a playback step of, when application control information for synchronizing the content transmitted via the broadcast wave and the content transmitted via the communication path, which information includes information regarding the content transmitted via the communication path, is received from at least the broadcast wave of the broadcast wave or the communication path, performing the synchronization process and playing back the content.

[0267] This allows application control information transmitted over a transmission path that serves as an entry point, such as a broadcast wave, to be acquired, and if the information includes information about the content transmitted over the communication path and is used to synchronize the content transmitted over the broadcast wave with the content transmitted over the communication path, the synchronization process can be performed.

[0268] Also, for example, in the receiving step, the application control information may be received prior to receiving the content, and if the application control information includes location information indicating the location from which the content is to be obtained, the content may be received by obtaining the content based on the location information.

[0269] Also, for example, in the receiving step, the application control information is received prior to receiving the content, and if the application control information includes information indicating the source of location information indicating the source of the content, the location information may be obtained based on the information indicating the source of the location information, and the content may be received by obtaining the content from the obtained location information.

[0270] In addition, a transmitting device in one aspect of this embodiment is a content transmitting device capable of transmitting content using broadcast waves and a communication path, and when transmitting content using both broadcast waves and a communication path, is equipped with an information transmitting unit that includes information regarding the content to be transmitted via the communication path in application control information, which information is used to synchronize the content via the broadcast waves with the content via the communication path when received by the receiving side, and transmits the information using at least the broadcast waves of the broadcast waves and the communication path.

[0271] In addition, a receiving device in one aspect of this embodiment includes a receiving unit that receives content transmitted using both broadcast waves and a communication path, and a playback unit that, when receiving application control information that includes information for synchronizing the content transmitted via the broadcast waves and the content transmitted via the communication path and that performs the synchronization process and plays the content, when application control information is received that includes information regarding the content transmitted via the communication path.

[0272] (Embodiment 2) Example 1 For example, in the third variant of the first embodiment, in Figures 6A to 7B, etc., a method for storing location information etc. in a case where broadcasting is performed using TS and communication is performed using DASH, RTP, etc. is described, but this is not limited to this.

[0273] In this embodiment, a specific example of a method for storing location information will be described as Example 1.

[0274] Fig. 14 is a diagram illustrating an example of a data structure of service information in the broadcasting and communication cooperative service according to Example 1 of Embodiment 2. Fig. 14 illustrates an example of a descriptor (location information descriptor) indicating location information such as an MPD. Note that the location information may be included in the transmission path identification descriptor described above. Therefore, the location information descriptor may be considered to be equivalent to the transmission path identification descriptor.

[0275] In this embodiment, the descriptor is stored in the PMT or in section data different from the PMT.

[0276] The information indicated by this descriptor includes a transmission format indicating the type of actual data referenced by the location information, the location information, and a field indicating synchronization information between the PCR in broadcasting and the data on the communication side.

[0277] In this embodiment, location information indicates a reference destination of entity data of location information. Here, an example is shown in which the entity data of location information is an MPD, and MPD is indicated as the transmission format, and synchronization information between PCR and NTP is indicated as synchronization information.

[0278] Since the MPD is location information used in DASH, it is possible to indicate DASH as the transmission format and indicate the reference destination of the MPD as the location. In cases where the transmission format can be identified by the extension of the URL of the location information, etc., it is not necessary to include the transmission format field. In addition, there are two ways to transmit the MPD: either within the broadcast or via a communication network. When transmitting within the broadcast, the private section of the MPEG-2 TS is used.

[0279] Therefore, the location information of the MPD can indicate identification information of the TS packet that stores the MPD in the transport stream, such as the PID of the private section, when transmitted within a broadcast, or can indicate information such as a URL when transmitted via a communications network.

[0280] [Receiving method] An example of the operation of the receiving device when analyzing a descriptor indicating location information and synchronously playing back broadcast and communication content will be described below as a receiving method in this embodiment.

[0281] FIG. 15 is a flowchart illustrating an example of an operation on the receiving side in the broadcast communication cooperative service according to the first example of the second exemplary embodiment.

[0282] First, in step S801, the location information descriptor stored in the PMT or the like is analyzed.

[0283] Next, in step S802, it is determined whether an MPD exists in the broadcast. If an MPD exists in the broadcast (an MPD is transmitted via the broadcast) (Yes in S802), the process proceeds to step S803, where the MPD entity data is obtained from the TS packet having the PID indicated by the location information. On the other hand, if an MPD does not exist in the broadcast (No in S802), the MPD is obtained from the communication server based on the URL or the like indicated in the location information.

[0284] Next, in step S805, the data to be acquired from the DASH content is determined based on the analysis result of the MPD, and the data is acquired by download (or progressive download, etc.).

[0285] Next, in step S806, the broadcast content and the communication content are played back in synchronization based on the synchronization information contained in the location information descriptor, or, if MPEG-2 TS timeline extension is used, the synchronization information obtained from the TS packet that stores the timeline extension information.

[0286] Note that when timeline extension is used, synchronization information does not need to be included in the location information descriptor. Furthermore, if synchronized playback of DASH content and broadcast content is not required, synchronization information does not need to be transmitted. In this case, whether synchronized playback of the two is required may be determined based on the synchronization information in the location information descriptor or whether synchronization information is present in the data for timeline extension. Whether synchronized playback is required may also be indicated separately.

[0287] If synchronized playback is not required, in step S806, the start and end of playback of the DASH content can be determined based on user instructions or control commands in the Hybridcast application, etc. In this case, it is assumed that whether or not to obtain data via communication has been determined in the previous stage of S801.

[0288] Although an example in which an MPD is acquired and DASH content is played back has been described with reference to FIG. 15, the same applies to cases in which data in other formats such as RTP or TS is acquired and played back.

[0289] In the timeline extension, an access unit for storing timeline extension information is defined, and both a descriptor indicating location information and a descriptor indicating synchronization information can be stored in the access unit.

[0290] Therefore, both location information and synchronization information may be indicated by a timeline extension without transmitting a location information descriptor. In the current timeline extension, it is not possible to indicate a PID as location information, so the field indicating the scheme type of location information may be extended to enable signaling of a PID.

[0291] In addition, the upper limit of the PMT section size is limited to 1021 bytes, and depending on the URL in the location information, this limit may be exceeded. Although it is possible to store PMT sections in separate sections, it is particularly desirable to store the PMT in a single section.

[0292] Therefore, if the section size of the PMT exceeds 1021 bytes, the location information descriptor may be transmitted in a section different from the PMT. Note that if the location information indicates a PID, it can be contained within the PMT size limit and can be included in the PMT, so the section that stores the location information may be switched depending on whether the location information is a PID or a URL.

[0293] Example 2 In the first embodiment, it has been described that location information can also be indicated in a TEMI (Timeline and Extend Media Information stream) access unit in timeline extension.

[0294] Specifically, the temi_location_descriptor can be used to describe the URL of the content on the communication side. The temi_location_descriptor can describe the URLs of multiple contents and does not have any data size restrictions like the section size of the PMT, allowing for flexible operation when describing URLs.

[0295] On the other hand, when the location information indicates the PID of a TS packet in a transport stream, the data size of the location information is small, and the delay associated with obtaining the location information can be reduced by referencing the location information descriptor and obtaining the location information when analyzing the PMT. Therefore, it is desirable to be able to store the location information in both the location information descriptor and the temi_location_descriptor in the TEMI access unit.

[0296] An example of the syntax (data structure) of the location information descriptor in this embodiment will be described below.

[0297] Fig. 16A is a diagram illustrating an example of the syntax of a location information descriptor in Example 2 of Embodiment 2. Fig. 16A illustrates an example of the syntax of a location information descriptor for storing location information in either a location information descriptor or a TEMI access unit.

[0298] In this embodiment, it is assumed that the synchronization information with the PCR is described using the temi_timeline_descriptor of the TEMI access unit, and is not included in the location information descriptor. The semantics of each field shown in Fig. 16A will be described.

[0299] "data_format" is the same as the transmission format shown in Fig. 14. In other words, it indicates the format of meta information for playback control used in the service, such as the MPD in DASH, the playback control meta file in the IPTV Forum's VOD (Video On Demand) specifications, or the TTS (Time-stamp TS) specified by the IPTV Forum, etc. It may indicate identification information for the stream itself, rather than meta information, such as a TTS, MP4 file, or the AV encoded data itself. It may also indicate an MPT, PA message, MMT packet, asset, etc. in MMT.

[0300] For example, temporal scalability can be achieved in a video encoding format such as H.265. Assume that a base layer of 60 fps is transmitted via broadcasting, and encoded data of an enhancement layer for increasing the frame rate from 60 fps to 120 fps is transmitted via communication. In this case, the location information of the communication content only needs to indicate the URL of the encoded stream of the enhancement layer. Information such as the resolution and encoding format of the encoded stream can be obtained from the broadcast data transmitting the base layer.

[0301] "location_type" is used to identify whether the location information is indicated by the PID of the TS in broadcasting or the URL in communication. Here, location_type = 0 indicates the PID of the TS in broadcasting. Note that the location information descriptor can also be used in formats other than TS, such as MPEG Media Transport (MMT) of MPEG. In formats other than TS, "location_type" does not need to be used. For example, other information for identifying the location, such as the packet_id of the MMT packet in MMT, may be used.

[0302] "PID" indicates the PID of the TS packet. If the broadcast is made up of multiple transport streams, the transport stream identification number may also be stored.

[0303] "url_location" indicates whether the URL of the communication content is stored in the location information descriptor or in the TEMI access unit. In this embodiment, when url_location = 0, it is stored in the location information descriptor. When url_location is 1, the URL of the communication content is stored in the temi_location_descriptor in the TEMI access unit.

[0304] "url_length" indicates the byte length of "url_path." "url_path" indicates the URL data.

[0305] Fig. 16B is a diagram showing an example of the syntax of a location information descriptor in Example 2 of Embodiment 2. Fig. 16B shows an example of the syntax of the location information descriptor different from that shown in Fig. 16A. The difference from the syntax shown in Fig. 16A is that when location information is stored in a TEMI access unit, the data_format field does not exist.

[0306] Here, the Temi_location_descriptor can indicate the service type of the TEMI in a field called service_type. This service type corresponds to data_format. Therefore, data_format information is indicated in the service_type field.

[0307] 16A, the data_format field and the service_type of the temi_location_descriptor may both exist. In this case, both fields indicate the same information.

[0308] In the temi_location_descriptor, it is also possible to indicate only the URL of the communication content without signaling the service_type. Therefore, when using the syntax of Fig. 16A, the data_format of the location information descriptor may be referenced as the transmission format, and the service_type of the temi_location_descriptor may not be signaled.

[0309] Fig. 16C is a diagram illustrating an example of the syntax of the location information descriptor in Example 2 of Embodiment 2. Fig. 16C illustrates an example of the syntax of the location information descriptor that is different from the syntax of the location information descriptor illustrated in Fig. 16A and Fig. 16B.

[0310] The difference from Fig. 16A is that a conditional branch for url_location is performed first. In other words, when url_location = 0 and location information is in the location information descriptor, the PID of the broadcast TS or the communication URL is stored according to location_type. On the other hand, when url_location = 1, location_type is not described in the location information descriptor, and the location_type is indicated in the service_type field in the temi_location_descriptor in the TEMI access unit, and the PID of the broadcast TS or the communication URL is stored in the temi_location_descriptor.

[0311] Fig. 16D is a diagram showing an example of the syntax of the location information descriptor in Example 2 of Embodiment 2. Fig. 16D shows an example of the syntax of the location information descriptor different from the syntax of the location information descriptor shown in Figs. 16A to 16C.

[0312] The difference from Fig. 16A is that url_location and location_type are integrated. When location_type = 0, it indicates the PID of the broadcast, and when location_type = 1, it indicates the URL of the communication. When location_type = 2, it indicates that the PID of the TS in the broadcast or the communication URL is stored in the temi_location_descriptor in the TEMI access unit.

[0313] The data and data structure of the location information descriptor syntax are not limited to the above example. For example, the location type and format type may be combined and used in combination with other data. Furthermore, in cases where the transmission format can be identified by the extension in the URL of the location information, for example, the transmission format field need not be included. Furthermore, for example, if a location information descriptor does not exist, the location information may be represented by temi_location_descriptor, and the url_location field may be omitted.

[0314] Example 3 An example of location information different from that described in the second embodiment will be described below.

[0315] (Other examples of location information) For example, if two or more types of timelines exist in the same program, each type of timeline may contain multiple TEMI streams.

[0316] In this case, multiple pieces of location information may be stored in the location information descriptor. When multiple pieces of location information are stored, loops equal to the number of TEMI streams are created in the location information descriptor, and location information corresponding to each TEMI stream is stored. In addition, as a method of indicating the correspondence between multiple location information loops in the location information descriptor and multiple TEMI streams, for example, the correspondence may be indicated by matching the order of the location information loops with the order of the ES loops (PMT second loop) indicating the TEMI streams. In addition, when two or more types of timelines exist, the location information may not be stored in the location information descriptor, but may be stored in the temi_location_descriptor of the TEMI access unit, or the location information descriptor may be stored in the ES loop (PMT second loop).

[0317] (Location information update) It is desirable to be able to handle updates to the content of location information such as meta information.

[0318] For example, a reload flag can be added to the location information descriptor in the PMT, and when the content of the location information is to be updated, reload=1 can be set, and when reload=1 is set, the receiving device can assume that the content of the location information has been updated and reacquire the PID, URL, etc. stored in the location information. If the location information such as the PID or URL has not been updated and only the data has been updated, only the data can be reacquired.

[0319] Furthermore, the location information itself, or information indicating whether the content of data such as an MPD whose acquisition source is indicated by the location information has been updated, may be indicated independently.

[0320] Alternatively, the location information descriptors in the periodically transmitted PMT may be checked sequentially. However, since this sequential checking process is heavy, it is also possible to generate separate section data for storing the location information descriptors and event sections for notifying updates, and transmit these separately.

[0321] The receiving device can determine whether the location information has been updated by checking the version number in the section. Also, if the location information is transmitted in a broadcast section, the version number of the location information section is updated to indicate that the meta information has been updated.

[0322] Furthermore, after starting to acquire data on the communication side based on location information acquired from broadcasting, updated content of the location information may be acquired through communication.

[0323] [Receiving method] Next, as a receiving method in this embodiment, an example of the operation of the receiving device when analyzing a descriptor indicating location information and synchronously playing back broadcast and communication content will be described.

[0324] FIG. 17 is a flowchart illustrating an example of an operation on the receiving side in the broadcast communication cooperative service according to Example 3 of the second exemplary embodiment.

[0325] Step S804 in Fig. 15 is changed to steps S906, S907, and S908 in Fig. 17. The other operations (steps S901 to S905) are the same as those in Fig. 15 (steps S801 to S803, step S805, and step S806), so a detailed description will be omitted.

[0326] In step S906, it is determined whether the URL for obtaining the MPD or the like is stored in the location information descriptor or the TEMI access unit. If it is in the location information descriptor (Yes in S906), the process proceeds to step S907, where the location information descriptor is analyzed and the MPD is obtained from the communication server based on the URL indicated in the location information. On the other hand, if it is determined in step S906 that it is stored in the TEMI access unit (No in S906), the MPD is obtained from the communication server based on the URL indicated in temi_location_descriptor in the TEMI access unit.

[0327] Although FIG. 17 shows an example in which MPD is indicated as format information, broadcast content and communication content can be synchronously played back by performing the same flow of operations even when other meta information is used.

[0328] Fig. 18 is a flowchart showing another example of the operation of the receiving side in the broadcasting and communication cooperative service of Example 3 of Embodiment 2. Fig. 18 shows the operation when the format information is meta information other than MPD. More specifically, when the format information indicates the format of entity data such as a stream rather than meta information such as MPD, the operation is shown when the URL of the entity data of the stream is acquired instead of the URL of the meta information in step S907 and step S908 shown in Fig. 11.

[0329] First, in step S1001, the receiving device analyzes the location information descriptor.

[0330] Next, it is determined whether the data indicated in the format exists in the broadcast (step S1002). If data exists in the broadcast (Yes in S1002), the process proceeds to step S1003, where the PID indicated in the location information is acquired. Since it is not assumed here that actual data such as streams will be included in the broadcast, if data exists in the broadcast, the format is determined to be metadata.

[0331] Next, a meta information file is acquired from the broadcast stream based on the PID (step S1004), and communication data to be acquired is determined (step S1005).

[0332] On the other hand, if data exists in the communication in step S1002 (No in S1002), the process proceeds to step S1008, where it is determined whether the URL of the communication data exists in the location information descriptor or in the temi_location_descriptor of the TEMI access unit. Then, the URL is acquired in step S1009 or step S1010, depending on the case.

[0333] In step S1011, it is determined whether the format is meta information. If the format is meta information (Yes in S1011), the process proceeds to step S1012, where the meta information is acquired from the communication stream based on the URL, and the process proceeds to step S1005, where the communication data to be acquired is determined.

[0334] After the communication data to be acquired is determined in step Sp1005, or if it is determined in step S1011 that the format is not meta information, the process proceeds to step S1006, where the communication data is acquired.

[0335] Finally, in step S1007, the broadcast content and the communication content are synchronously played back based on the synchronization information included in the location information descriptor or the synchronization information indicated by the timeline extension of the MPEG-2 TS.

[0336] Example 4 So far, we have explained that it is determined whether the broadcast content and the communication content are played back in synchronization, and if they are, the broadcast content and the communication content are acquired and played back in synchronization, but this is not limited to this.

[0337] In this embodiment, information indicating whether the reference clock information for audio and video transmitted by broadcasting is the same as the reference clock information for audio and video transmitted by communication is included in the service information (transmission identification descriptor, etc.), and the operation based on this information will be described.

[0338] [Information on whether the reference clock (timeline) between broadcasting and communication is synchronized] When content that uses broadcasting and communication is transmitted using MMT, DASH, RTP, hybridcast, or the like, information indicating whether the reference clock information for audio and video transmitted by broadcasting is the same as the reference clock information for audio and video transmitted by communication may be stored in a transmission identification descriptor, program information, EPG, EIT, etc.

[0339] For example, if the content transmitted by broadcasting and communication operates based on a common reference clock (e.g., by adding a timestamp), information indicating that the content operates based on the common reference clock is stored. Also, if the content transmitted by broadcasting and communication operates based on different reference clocks, information indicating that the content operates based on different reference clocks is stored.

[0340] Also, only when it is indicated that different reference clock information is used for broadcasting and communication, information necessary for reference clock synchronization (for example, timeline extension information, etc.) may be indicated. Also, it may be possible to indicate the storage location of the information necessary for reference clock synchronization, the type of information necessary for reference clock synchronization, the method of reference clock synchronization, etc.

[0341] Here, in synchronizing the reference clock, it is possible to align it with the reference clock used in either broadcasting or communication.

[0342] For example, if PCR (Program Clock Reference) is used in broadcasting and NTP (Network Time Protocol) is used in communications, the type and method of reference clock synchronization may be indicated as follows: the NTP-based DTS and PTS for video and audio can be converted to the PCR-based DTS and PTS for broadcasting and communications, thereby synchronizing the reference clocks for broadcasting and communications. Alternatively, the type and method of reference clock synchronization may be indicated as follows: the DTS and PTS for broadcasting and communications are converted so as to synchronize with a specific clock used in the receiving device.

[0343] It is also possible to analyze identification information indicating the type of information and method required for reference clock synchronization, and perform reference clock synchronization using a method based on the identification information.

[0344] Furthermore, if there are multiple streams with different reference clocks, information indicating that there are multiple reference clocks with different reference clocks may be stored in the descriptor. A descriptor may be indicated for each different reference clock, or a single descriptor may be used. Information indicating the correspondence between the reference clock and the program using that reference clock may also be stored.

[0345] The information indicating whether the reference clocks are the same may be indicated as a descriptor as described above, or other descriptors, tables, sections, etc. may be used. It may also be indicated by the presence or absence of information necessary for clock synchronization (e.g., timeline extension information, etc.). If the information necessary for clock synchronization is present, it may be determined that the clock information is different. Alternatively, attribute information of the communication content indicated in a transmission identification descriptor, etc. (e.g., information about the format or type, or location information or an extension described in a URL) may be used to indicate that the clock information is different. In the case of hybridcast, it may be stored in an AIT controlled section or an application.

[0346] If the receiving device determines that different clock information is being used, it synchronizes the reference clock information for broadcasting and communication, and if it determines that common clock information is being used, it determines that clock synchronization is not necessary.

[0347] In addition, the receiving device may take into consideration not only the identification result of whether the reference clock information of the data stored in the transmission identification descriptor, etc. is the same, but also all factors such as user selection and user settings via the user interface, the intentions of the content provider, service operator, or broadcasting station, the specifications and specifications of the receiving device, and the intentions of the receiver manufacturer, and determine whether to actually synchronize the reference clocks of the broadcast content and the communication content.

[0348] Furthermore, when the receiving device determines to synchronize with the reference clock, the timing of the actual clock synchronization may start after the determination, or may start when information regarding synchronization is acquired without waiting for the determination, or may synchronize with the time when acquisition of the communication content starts (for example, a certain time before the start of content acquisition, or the same time as the start of acquisition).

[0349] In addition, if clock recovery of the reference clock (e.g., broadcast PCR) that is the reference source has not been completed (the clock has not yet been made available for use by smoothing out the effects of jitter, etc.), clock synchronization with the reference destination may be started once clock recovery of the reference clock information of the reference source has been completed.

[0350] If the EPG indicates whether the reference clocks for broadcasting and communications are synchronized, it may be possible to determine whether reference clock synchronization is necessary and start synchronization of the reference clocks before the start of broadcasting, as in the case of pre-buffering of communications content. In this way, by synchronizing the reference clocks earlier, services can be provided to viewers more quickly.

[0351] In addition, the information indicating whether the reference clock is the same is not limited to a combination of broadcasting and communication, but can be applied when data is transmitted over the same route, or when different reference clock information is used in data obtained from multiple routes such as broadcasting, communication, and storage formats.

[0352] Note that some or all of the functions and processes described in this embodiment may be implemented in hardware or software, and some may be implemented in hardware or software.

[0353] For example, when implementing in software, functions such as instructing the functions and processing described in this embodiment, notifying the status of the receiving function by PUSH, and obtaining by PULL may be packaged and provided as API functions.

[0354] API functions can be executed from applications. When implemented as an application, it can be implemented as a resident application or an application such as HTML5. The above API can also be implemented as a means of passing data between applications and notifying status.

[0355] Here, the API functions related to information on whether the reference clock is synchronized include, for example, the following 1) to 9).

[0356] 1) Obtains information on whether the reference clock information for broadcast content and communication content is the same. 2) Obtains information on whether reference clock synchronization is required. 3) Obtains the type of reference clock information and synchronization method for each. 4) Obtains information required for clock synchronization (timeline information, etc.). 5) Obtains the source of information required for clock synchronization. 6) Takes the clock information of the reference source as an argument and returns the clock information of the synchronized reference destination. For example, if synchronization is not achieved, returns a value indicating that synchronization is not achieved. 7) Instructs the start of synchronization of each other's reference clocks. 8) Obtains the status of whether reference clock synchronization is achieved. 9) Notifies that reference clock synchronization has been achieved.

[0357] [Receiving method] Below, using the figures, we will explain an example of the operation of the receiving method in this embodiment, when attribute information and location information are stored in the broadcast program information and the receiving device determines whether to play the broadcast content and the communication content synchronously.

[0358] Fig. 19 is a flowchart illustrating an example of the operation of the receiving side in the broadcasting and communication cooperation service according to Example 4 of Embodiment 2. Note that the operation of the flowchart illustrated in Fig. 19 is applicable to a broadcasting and communication cooperation service using any combination of multiplexing methods such as MMT, DASH, and RTP. It is also applicable to hybridcast.

[0359] In FIG. 19, it is assumed that the broadcast content and the communication content are synchronized, and the determination of whether or not to synchronize the broadcast content and the communication content is omitted.

[0360] Furthermore, steps S1101 and S1102 are the same operations as steps S401 and S402 in FIG. 9, and therefore a description thereof will be omitted.

[0361] Next, in step S1103, the receiving device determines whether to acquire the communication content. If it determines to acquire the communication content (Yes in S1103), it proceeds to step S1104, receives data from both the broadcast and communication transmission paths, and then in the following step S1105, determines whether the reference clocks of the broadcast content and the communication content are the same or different.

[0362] If it is determined in step S1105 that the reference clocks are different (Yes in S1105), the process proceeds to step S1106, where the reference clocks of the broadcast content and the communication content are synchronized, and in step S1107, both are played back in synchronization.

[0363] On the other hand, if it is determined in step S1105 that the reference clocks are the same (No in S1105), the reference clocks are not synchronized, and synchronous playback is performed using a common clock.

[0364] After step S1105, a process for determining whether reference clock synchronization is necessary may be performed. For example, depending on the type and method of clock synchronization, it may be determined whether the capabilities of the receiving device support clock synchronization, whether clock synchronization is required as a receiver specification, or whether clock synchronization is required by the user. Then, based on the results of step S1105 and the above determination, it may be determined overall whether reference clock synchronization is required for broadcasting and communication, and the process may proceed to step S1106 or step S1107.

[0365] Furthermore, the synchronization of the reference clocks in step S1106 may be performed prior to step S1104. This is because, for example, when playback is started after pre-buffering received content data, decoding and playback may be started after confirming that data with a PTS of T1 in the broadcast content and data with a PTS of T1 in the communication content (assuming that the PTSs of both are already synchronized) have been received. This is because, when determining whether the data to be played back in synchronization with each other are available, it is necessary that the reference clocks of both are synchronized.

[0366] In addition, if clock synchronization is not possible in step S1106 because clock synchronization information cannot be acquired or because of the receiver specifications, it may not be possible to provide the user with a service that combines broadcasting and communication. In such cases, it may be possible to determine whether to receive the data transmitted by communication in step S1103 by determining whether synchronization is required or whether playback is possible without synchronization.

[0367] In step S1103, in addition to the information that can be identified by the transmission path identification descriptor, the decision as to whether to actually receive the data transmitted by communication may be made by taking into consideration all of the following: the user's selection and settings, the intentions of the content provider, service provider, or broadcasting station, the specifications and specifications of the receiving device, and the intentions of the manufacturer.

[0368] [Receiver] Next, a description will be given of an example of the configuration of a receiving device that realizes the operation shown in Fig. 19. Fig. 20 is a block diagram showing an example of the configuration of a receiving device according to Example 4 of Embodiment 2.

[0369] The receiving device 1100 shown in Figure 20 includes an identification information acquisition unit 1101, a determination unit 1102, a communication use determination unit 1103, a Loc information acquisition unit 1104, a broadcast receiving unit 1105, a communication receiving unit 1106, a reference clock determination unit 1107, and a reproduction unit 1108.

[0370] The identification information acquisition unit 1101 to the communication reception unit 1106 are the same as the identification information acquisition unit 301 to the communication reception unit 306 described in FIG. 8, and therefore a description thereof will be omitted.

[0371] The reference clock determination unit 1107 has a function of performing the process of step S1105 shown in Fig. 19. Furthermore, the reference clock determination unit 1107 may perform a process of determining whether or not the reference clocks are different, and then determining whether or not synchronization of the reference clocks is required as described above.

[0372] Based on the method determined by the result of the determination in the reference clock determination unit 1107, the reproduction unit 1108 synchronizes the reference clocks if they are different, and then decodes and reproduces the broadcast content or communication content.

[0373] The functions, configuration of the receiving device, and receiving method described in this modified example are merely examples, and are not limited to these, and may be anything that can achieve similar functions and effects.

[0374] [Effects of the second embodiment] As described above, according to this embodiment, identification information indicating whether content including audio and video is transmitted by broadcasting and communication in combination, and information indicating the dependency between data transmitted over both transmission paths when broadcasting and communication are used in combination, may be generated and transmitted as content management information. Here, for example, the information indicating the dependency between data may include whether the data transmitted over both transmission paths are synchronously reproduced. Furthermore, the information indicating the dependency between data may include whether the clock information of the data transmitted over both transmission paths is the same.

[0375] This allows the transmission path over which content including audio and video is transmitted, and the dependencies between data transmitted over different transmission paths, to be obtained at the start of content reception, thereby reducing delays in determining the assets to receive and in starting to receive communication content.

[0376] Furthermore, according to this embodiment, location information of data transmitted in communication may be included in content management information. Here, the location information of the data to be transmitted may be, for example, an MPD in MPEG-DASH. Furthermore, the content management information may store information indicating a source of location information, rather than actual data of location information such as an MPD.

[0377] This allows the transmission path over which content including audio and video is transmitted, and the dependencies between data transmitted over different transmission paths, to be obtained at the start of content reception, thereby reducing delays in determining the assets to receive and in starting to receive communication content.

[0378] Furthermore, according to this embodiment, the receiving device may analyze the management information of the content to determine the transmission path for receiving the content and the data to be received on each transmission path. For example, if the clock information of the data transmitted on both transmission paths is different, auxiliary information required for clock synchronization between the data may be obtained, and the DTS and PTS in each data may be synchronized, decoded, and played back. Furthermore, if the data transmitted on both transmission paths are to be played back synchronously, auxiliary information required for clock synchronization between the data may be obtained, and the DTS and PTS in each data may be synchronized, decoded, and played back.

[0379] As a result, in a receiving device that receives only broadcast data, it is possible to reproduce broadcast data in the same manner as in conventional broadcast reception, while also being able to handle reproduction of communication data.

[0380] Furthermore, a mechanism can be provided for receiving devices to play back broadcast and communication data in synchronization.

[0381] Furthermore, even if the clocks of data transmitted over a plurality of transmission paths are not synchronized, the clocks can be synchronized by acquiring auxiliary information required for clock synchronization, and data can be reproduced in a synchronized manner.

[0382] As described above, according to this embodiment, it is possible to realize a content transmission method, receiving method, transmitting device, and receiving device that enable quick access to content via communication when content that combines broadcasting and communication is played back on the receiving side.

[0383] Here, for example, a transmission method in one aspect of this embodiment is a content transmission method capable of transmitting content using broadcast waves and a communication path, and when transmitting content using both broadcast waves and a communication path, includes an information transmission step of including information regarding the content to be transmitted via the communication path in application control information, which information is used to synchronize the content via the broadcast waves with the content via the communication path when received by the receiving side, and transmitting the information using at least the broadcast waves of the broadcast waves and the communication path.

[0384] As a result, when content is transmitted using broadcast waves and a communication path, information for synchronizing the content transmitted by the broadcast waves with the content transmitted by the communication path when received by the receiving side is included in the application control information and transmitted, so that when the receiving side receives the application control information, the receiving side can quickly access the content transmitted by communication and the contents can be synchronized.

[0385] Also, for example, in the information transmission step, the application control information may be transmitted prior to transmitting the content, and the application control information may further include location information indicating the source from which the content is obtained or information indicating the source from which the location information is obtained.

[0386] Furthermore, for example, in the information transmitting step, the application control information may be transmitted by including difference information between a reference clock of the content via the broadcast wave and a reference clock of the content via the communication path.

[0387] Also, for example, in the information transmission step, the application control information may be transmitted, thereby synchronizing the reference clock of the content via the communication path with the reference clock of the content via the broadcast wave based on the difference information, thereby allowing the receiving side to achieve the synchronization.

[0388] Furthermore, a receiving method in one aspect of this embodiment includes a receiving step of receiving content transmitted using both a broadcast wave and a communication path, and a playback step of, when application control information for synchronizing the content transmitted via the broadcast wave and the content transmitted via the communication path, which information includes information regarding the content transmitted via the communication path, is received from at least the broadcast wave of the broadcast wave or the communication path, performing the synchronization process and playing back the content.

[0389] This allows application control information transmitted over a transmission path that serves as an entry point, such as a broadcast wave, to be acquired, and if the information includes information about the content transmitted over the communication path and is used to synchronize the content transmitted over the broadcast wave with the content transmitted over the communication path, the synchronization process can be performed.

[0390] Here, for example, in the receiving step, the application control information may be received prior to receiving the content, and if the application control information includes location information indicating the location from which the content is to be obtained, the content may be received by obtaining the content based on the location information.

[0391] Also, for example, in the receiving step, the application control information is received prior to receiving the content, and if the application control information includes information indicating the source of location information indicating the source of the content, the location information may be obtained based on the information indicating the source of the location information, and the content may be received by obtaining the content from the obtained location information.

[0392] Also, for example, in the playback step, the application control information including difference information between the reference clock of the content via the broadcast wave and the reference clock of the content via the communication path is received in the receiving step, and if the reference clock of the content via the broadcast wave and the reference clock of the content via the communication path are different, the content may be synchronized by synchronizing the reference clock of the content via the communication path with the reference clock of the content via the broadcast wave based on the difference information, and the content may be played back.

[0393] While the transmission method and reception method according to one or more aspects of the present invention 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 and configurations constructed by combining components of different embodiments may also be included within the scope of one or more aspects of the present invention.

[0394] For example, 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 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.

[0395] Furthermore, for example, the attribute information may include information indicating whether the clock information of the audio or video transmitted by broadcasting is the same as the clock information of the audio or video transmitted by communication.

[0396] Furthermore, in synchronizing the reference clock in S406, if the attribute information includes information indicating whether the reference clock information of multiple components is the same, and the receiving side can obtain that the reference clock information is different based on the attribute information, the reference clocks for broadcasting and communication may be synchronized using the above method.

[0397] Furthermore, when content is transmitted using both broadcast waves and a communication path, a transmission path identification descriptor may be transmitted, and when content is transmitted using only broadcast waves, the transmission path identification descriptor may not be transmitted. With this configuration, the receiver can determine whether content is transmitted using both a communication path and broadcast waves or only broadcast waves, based on whether the transmission path identification descriptor is included.

[0398] Furthermore, although the attribute information may include a method for synchronizing clock information of streams transmitted over different transmission paths such as broadcasting and communication, this is not limitative. The attribute information may include a method for synchronizing information indicating whether clock information of streams transmitted over different transmission paths such as broadcasting and communication is synchronized with each other, or a method for synchronizing the information. [Industrial Applicability]

[0399] The present invention is useful as a content transmission method, a content reception method, etc., that can transmit content using broadcast waves and communication paths. [Explanation of symbols]

[0400] 11 Identification information acquisition unit 14, 104, 305, 405, 1105 Broadcast receiving unit 100, 300, 400, 1100 receiving device 101, 301, 401, 1101 Identification information acquisition unit 102 Asset Determination Department 103 Judgment section 105, 306, 406, 1106 Communication receiver 302, 402, 1102 Decision Section 303, 403, 1103 Communication combined use determination unit 304, 404, 1104 Loc information acquisition section 407 Synchronization Judgment Unit 408, 1108 Reproduction Department 1107 Reference clock determination unit

Claims

[Claim 1] a receiving step of receiving the content transmitted using the broadcast wave and the communication path; a reproduction step of reproducing the content when control information is received, the control information including information indicating that the content is transmitted via the communication path and information for reproducing the content via the broadcast wave and the content via the communication path, the information being related to the content transmitted via the communication path; In the receiving step, a base layer of the content is received using the broadcast wave and an enhancement layer is received using the communication path; In the receiving step, information indicating which asset of the base layer corresponds to which asset of the enhancement layer is received using the communication path; In the receiving step, information indicating a type of control information of the content transmitted through the communication path is received using the broadcast wave; In the receiving step, location information indicating a source of the content or information indicating a source of the location information is received. Receiving method.

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