Receiving device, broadcasting system, receiving method, and program

Abstract

To more securely come in contact with emergency broadcast audio while providing OBA.SOLUTION: A receiving unit receives multiplexed data in which a package containing a plurality of assets and an information table indicating configuration information of the package are multiplexed in a broadcast. A separating unit separates the information table from the multiplexed data. A selection unit selects a first audio asset containing object audio from the package on the basis of the information table. A decoding unit decodes audio data of a selected audio asset. The selection unit selects a second audio asset in preference to the first audio asset when detecting the second audio asset that does not contain an object voice.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present application relates to a receiving device, a broadcasting system, a receiving method, and a program.

Background Art

[0002] In next-generation terrestrial digital broadcasting (which may be referred to as the "terrestrial digital system" in the present application), the provision of object-based audio (OBA) is under consideration. According to OBA, a user, i.e., a receiver, can select a desired elementary audio from a plurality of types of elementary audio (objects). As elementary audio, the speech of an individual person, the sound of an object, etc. are applicable. As an encoding method for object-based audio, for example, there are the MPEG-H 3D Audio method and the Dolby (registered trademark) AC-4 method (which may be referred to as "AC-4 audio" in the present application).

[0003] For example, the audio decoding device described in Patent Document 1 includes a separation unit that acquires a bitstream and separates the bitstream into an encoded audio signal and encoded acoustic metadata, an acoustic metadata decoding unit that decodes the encoded acoustic metadata, an audio signal decoding unit that decodes the encoded audio signal, and an audio rendering unit that audio-renders the decoded audio signal based on the decoded acoustic metadata and outputs it as a reproduced sound.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] If an emergency broadcast occurs while OBA is being provided, it is possible that the audio for transmitting the emergency broadcast as an object may not be selected. For example, if an emergency such as a major earthquake occurs during a sports broadcast, and the audio for the emergency broadcast is provided by the commentator, then the commentator's commentary and ambient sounds are transmitted as objects. If the recipient selects ambient sounds, or if the volume set for the commentary is zero or very low, they may not be able to immediately access the emergency broadcast. [Means for solving the problem]

[0006] This application has been made to solve the above problems, and one aspect of this disclosure is a receiving device comprising: a receiving unit that receives multiplexed data in which a package containing a plurality of assets and an information table indicating the configuration information of the package are multiplexed; a separation unit that separates the information table from the multiplexed data; and a selection unit that selects a first audio asset containing object audio from the package based on the information table, wherein when the selection unit detects a second audio asset that does not contain object audio, it selects the second audio asset with priority over the first audio asset.

[0007] Another aspect of the present invention is a receiving method for a receiving device that receives multiplexed data via broadcast, in which a package containing a plurality of assets and an information table indicating the configuration information of the package are multiplexed; separates the information table from the multiplexed data; and selects a first audio asset containing object voice from the package based on the information table, wherein when the receiving device detects a second audio asset that does not contain object voice, it selects the second audio asset with priority over the first audio asset. [Effects of the Invention]

[0008] According to one embodiment of the present invention, recipients can more reliably access the audio of emergency broadcasts while providing OBA. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic block diagram showing an example configuration of a broadcasting system according to the first embodiment. [Figure 2] This is an explanatory diagram showing an example of operation of the receiving device according to the first embodiment. [Figure 3] This is a block diagram showing an example of the functional configuration of a broadcasting system according to the first embodiment. [Figure 4] This figure shows an example of the structure of a protocol stack according to the first embodiment. [Figure 5] This figure illustrates the data structure of MPT according to the first embodiment. [Figure 6] This figure illustrates the data structure of an MH-voice component descriptor according to the first embodiment. [Figure 7] This figure shows a first example of setting component tag values ​​according to the first embodiment. [Figure 8] This figure shows a second example of setting component tag values ​​according to the first embodiment. [Figure 9] This is a schematic block diagram showing an example of the hardware configuration of a receiving device according to the first embodiment. [Figure 10] This is a schematic block diagram showing an example of the hardware configuration of a transmitting device according to the first embodiment. [Figure 11] This is a flowchart illustrating the reception process according to the first embodiment. [Figure 12] This figure shows an example of the data structure of an emergency news descriptor according to the second embodiment. [Figure 13] This figure shows an example of setting the emergency voice stream number according to the second embodiment. [Figure 14] This is a flowchart showing a first example of the reception process according to the second embodiment. [Figure 15] This is a flowchart showing a second example of the reception process according to the second embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present application will be described with reference to the drawings.

[0011] <First Embodiment> First, an overview of the broadcast system S1 according to the first embodiment will be described.

[0012] FIG. 1 is a schematic block diagram showing a configuration example of the broadcast system S1 according to the present embodiment. The broadcast system S1 includes a transmission device 10 and a reception device 20. The transmission device 10 is mainly installed in a broadcasting station of a broadcaster and is used for providing a broadcast service. The broadcast service is provided using a broadcast transmission path. The broadcast service is, for example, a terrestrial digital broadcast service provided by the terrestrial digital method. In the example of FIG. 1, the broadcast transmission path includes a relay station Sa, and broadcast data is transmitted to the reception device 20 by radio waves via the relay station Sa. The relay station Sa may be fixed or movable. The broadcast service may be, for example, digital broadcast of broadcasting satellites (BS), digital broadcast of communication satellites (CS), etc. The broadcasting satellite or communication satellite functions as the relay station Sa. Note that the broadcast transmission path is a transmission path capable of unidirectionally and simultaneously transmitting various types of data. The broadcast transmission path is not necessarily limited to wireless, and may be configured to include a wired broadcast network (so-called cable TV) or a wired communication network. In the example of FIG. 1, the number of reception devices 20 is one, but generally, the number of reception devices 20 can be plural.

[0013] The transmission device 10 multiplexes a broadcast program package and an information table indicating the configuration information of the package to generate multiplexed data. The package contains a plurality of assets. An asset is a constituent element of the content of a broadcast program. Each individual asset is also called a "component", an "elementary stream" (ES), or simply a stream. Generally, the terms "asset", "component", "elementary stream", and "stream" may be used interchangeably, but in this application, the term "asset" is mainly used.

[0014] The transmission device 10 sends out a broadcast signal carrying the generated multiplexed data to a broadcast transmission path. In this application, sending out to a broadcast transmission path is called "transmitting by broadcast", and receiving various data transmitted on the broadcast transmission path may be called "receiving by broadcast". The broadcast signal may transmit application control information, control information regarding the presentation of an application, etc. The application control information transmits notification information of various application programs (which may be called "applications" or "apps" in this application) that are associated with the broadcast program, commands for startup and termination, and other control information related to execution. The control information regarding application presentation transmits the arrangement when displaying on a common display of the display screen (which may be called an "app screen" in this application) due to the execution of the application and the display screen of the broadcast program (which may be called a "broadcast screen" in this application), and whether the app screen can be presented, etc.

[0015] The receiving device 20 receives the broadcast signal and separates an information table from the multiplexed data carried by the received broadcast signal. The receiving device 20 refers to the separated information table to separate the first audio asset from the package and selects one or a set of object audio contained in the separated first audio asset. However, when the receiving device 20 detects a second audio asset that does not contain object audio, it selects the second audio asset with priority over the first audio asset. The receiving device 20 decodes the audio data of the selected audio and emits the audio according to the decoded audio data.

[0016] The broadcasting station server device 30 is a server device primarily used in broadcasting stations. The broadcasting station server device 30 acquires program information indicating the attributes of individual broadcast programs and provides it to service providers. Program information may include, for example, program title, program ID (Identifier), program summary, cast, broadcast date and time, etc. The broadcasting station server device 30 executes an API (Application Programming Interface) function to send the program information to the service provider server device 40.

[0017] A service provider is a business that provides some or all of various services using the broadcasting system S1. The service provider uses the service provider server equipment 40 to produce and distribute content and applications that constitute the broadcasting service. Broadcasting services may include broadcast-communication linked services that are provided in conjunction with broadcasting and communication. The broadcasting station server equipment 30 sends applications related to the broadcasting service to the receiving equipment 20 using a communication transmission path. The broadcasting station server equipment 30 provides server functions to realize individual related services. Related services include, for example, MPEG-H services, VOD program recommendation services, and multilingual subtitle services. The communication transmission path is a transmission path that enables the bidirectional transmission of various types of data, that is, a transmission path that enables the reception of data from a specific source and the transmission of data to a specific destination. A communication network can be mainly used as the communication transmission path.

[0018] MPEG-H is a set of standards developed by the ISO / IEC Moving Picture Experts Group (MPEG) for digital container standards, video compression standards, audio compression standards, and two adaptation test standards. MPEG-H services can include AC-4 audio assets. AC-4 audio enables the provision of OBA. An "object" in OBA refers to the individual audio elements that make up a program, i.e., elemental audio. Elemental audio includes, for example, human speech, noises, background sounds, and sound sources. In OBA, an audio signal is acquired for each audio element, and the acoustic characteristics can be controlled for each element. Examples of controllable acoustic characteristics include volume and frequency response. If multi-channel audio is applied in the receiving device 20, the channels used for sound emission may be controllable.

[0019] The broadcasting station server device 30 may transmit content to constitute related services. Examples of content to be transmitted include AC-4 audio data for OBA, VOD content for VOD program recommendation services, and subtitle data for multilingual subtitle services. The broadcasting station server device 30 may store various applications and, in response to an application inquiry from the receiving device 20, transmit response information indicating the applications that can be provided to the inquiring receiving device 20. The broadcasting station server device 30 may also transmit the requested application to the requesting receiving device 20 in response to an application request from the receiving device 20.

[0020] The receiving device 20 may have a network connection function in addition to the function of receiving digital broadcasts, enabling broadcast-communication collaboration services. For example, the receiving device 20 controls the execution of an application according to the application control signal received from the broadcast, and controls the display of the application screen and the broadcast screen according to the control information related to the application presentation. The receiving device 20 may also have a terminal collaboration function. A terminal is not limited to another receiving device 20, but may include user terminals such as smartphones and smart speakers. Through the terminal collaboration function, the receiving device 20 may enable access to various broadcast resources and operation of its own functions in response to requests from other terminals. As the destination for accessing broadcast resources, either the broadcast station server device 30 or the carrier server device 40, or a combination of either, may be specified.

[0021] The applications include, for example, an AC-4 audio digital mixer application. The receiving device 20 uses a digital mixer obtained from the broadcasting station server device 30 or the operator server device 40 to adjust the volume, various effects, and balance between materials for each sound material according to user operation. If multiple channels of speakers are available, the receiving device 20 may adjust the channel assignment for each material, and if multiple channels are assigned, it may adjust the volume balance between channels. Some applications may be pre-installed on the receiving device 20 and their execution may be controlled by application control signals.

[0022] In the example shown in Figure 1, there is one broadcasting station server device 30 and one carrier server device 40, but there may be two or more. Furthermore, one or both of the broadcasting station server devices 30 and 40 may be omitted. If the broadcasting station server devices 30 and 40 are omitted, the broadcast-communication collaboration service will not be provided. In that case, the receiving device 20 does not need to have network communication capabilities.

[0023] Figure 2 illustrates a case where, when a sports broadcast is aired, ambient sounds and commentary audio are provided by the OBA as two types of material. The receiving device 20 separates an information table from the multiplexed data received from the broadcast and identifies the video assets and audio assets indicated by the component tags described in the information table. Component tags are identifiers for identifying individual components, i.e., assets. The receiving device 20 extracts the video assets from the multiplexed data, decodes the extracted video assets, and displays the resulting video data on the display. The receiving device 20 extracts the audio assets from the multiplexed data, decodes the extracted audio assets, and uses an audio mixer to output the individual audio elements indicated in the resulting audio data to the speaker based on the audio characteristic parameters indicated at that time.

[0024] The receiving device 20 displays video of a baseball game being played at a baseball stadium and the settings screen U01 on its display. The settings screen U01 may also be displayed when an application is executed. Ambient sounds include the cheers of the crowd, the running of players, and the sound of the ball being hit. Commentary audio includes the voices of one or more commentators. The settings screen U01 represents slider bars for both the ambient sounds and the commentary audio. The slider bars are screen components that have a pointer and specify a quantity corresponding to the position of the pointer indicated by the user. The receiving device 20 accepts user input and can adjust the volume of each element sound as an acoustic characteristic to the volume corresponding to the position of the pointer indicated by the user. In the example on the left of Figure 2, the volume of the ambient sounds is set to maximum and the commentary audio is set to silent. In this state, even if an emergency occurs and emergency information is spoken by the commentator, the user receiving the device cannot immediately access the emergency information.

[0025] In this embodiment, when an emergency occurs, the transmitting device 10 acquires audio related to emergency information (sometimes referred to as "emergency audio" in this application) separately from the audio related to the sports broadcast, and generates a second audio asset indicating the acquired emergency audio. OBA may not be applied to the second audio asset. The transmitting device 10 includes the second audio asset in the broadcast program package, in addition to the first audio asset and video asset, and includes a component tag indicating the second audio asset in the information table. The transmitting device 10 transmits multiplexed data, which is obtained by multiplexing the information table and the package, via broadcast. The receiving device 20 can separate the information table from the received multiplexed data and detect the first audio asset and the second audio asset based on the component tag described in the separated information table. At this time, the receiving device 20 decodes the second audio asset with priority over the first audio asset, outputs the audio data obtained by decoding to the speaker 238 (described later), and plays it back. Therefore, even if commentary audio is not selected in OBA, the receiver can hear the emergency audio transmitted by the second audio asset. In the example on the right in Figure 2, the recipient can become aware of the earthquake by hearing the emergency voice message, "Earthquake!"

[0026] However, if the first audio asset related to the OBA is not selected, no adjustment of the acoustic characteristics for the elemental audio is performed. In that case, the receiving device 20 may not accept user input and may display a darker background for the audio OBA, as illustrated on the right side of Figure 2 (non-active display). This display indicates that the OBA can receive the first audio asset provided but has not been selected. The receiving device 20 may also display a darker background for the settings screen U01. This display indicates that user input for individual elemental audio is not accepted and that the adjustment of acoustic characteristics is disabled.

[0027] Next, an example of the functional configuration of the broadcasting system S1 according to this embodiment will be described. Figure 3 is a block diagram showing an example of the functional configuration of the broadcasting system S1 according to this embodiment.

[0028] The transmitting device 10 comprises a multiplexing unit and a transmitting unit. The multiplexing unit includes a multiplexer that acquires multiple assets constituting a broadcast program and multiplexes a package containing the multiple assets and an information table to generate multiplexed data. The transmitting unit includes a transmitter that sends packets containing the generated multiplexed data to the broadcast transmission path. The information table includes configuration information that shows the configuration of the package. As a multiplexing method, for example, the MMT-TLV (MPEG Media Transport-Type Length Value) method is used. In the MMT-TLV method, a TLV stream is transmitted as a broadcast signal that carries the multiplexed data.

[0029] In the MMT-TLV system, the MPT (MMT Package Table) is used as the information table. The MPT is described in the PA (Package Access) message, which is part of the MMT-SI (System Information). The MPT describes component tags for each asset included in the package. Multiple assets include at least one audio asset and one video asset. Audio assets can be of the following types: OBA-related components and channel-based audio (CBA). A single package may broadcast either one or both. Broadcasting both ensures that the audio of the broadcast program is provided even to receiving devices 20 that do not support OBA.

[0030] In the example in Figure 3, the multiplexing unit acquires audio data A11 as OBA and audio data A12-A14 as CBA, and constructs an advanced audio signal containing all of these as audio asset A1. Audio data A11 is audio data encoded using AC-4 audio. Audio data A12-A14 are audio data encoded using MPEG-4 audio for an audio signal representing a common voice. MPEG-4 audio is an example of an audio encoding scheme. There are different levels between audio data A12-A14. The level is an indicator of the scale of the listening environment and generally corresponds to a pair of audio channels and sampling frequency. The level is essentially a parameter that represents the circuit size of the decoder, i.e., its processing power. Each level corresponds to a pre-defined pair of sampling frequency, maximum number of input channels, maximum number of simultaneous decodings, and maximum number of output channels. A larger level number indicates higher processing power, i.e., one or more of the sampling frequency, maximum number of input channels, maximum number of simultaneous decodings, and maximum number of output channels are larger. The product of the sampling frequency and the bit depth (number of bits per sample) roughly corresponds to the bitrate per channel. The minimum values ​​for the maximum number of input channels, the maximum number of simultaneous decodings, and the maximum number of output channels are all 1.

[0031] The information table includes a descriptor for each audio asset indicating whether or not it is an audio asset consisting of audio data encoded in AC-4 audio. For example, for audio asset A1 shown in Figure 3, a descriptor indicating that it is an AC-4 audio asset is included. AC-4 audio encodes up to 11.1 channels of audio signals. In addition to background sounds and narration, dialogue (also called "dialogue audio") can be applied as elemental audio. Dialogue audio refers to the unique speech of each performer and is not limited to the speech that constitutes a dialogue.

[0032] When the multiplexing unit acquires an emergency audio asset related to emergency audio, it includes that emergency audio asset in the package. The emergency audio asset is a separate audio asset from audio asset A1, which is illustrated in Figure 3. In the emergency audio asset, an OBA is not provided, and audio data that can be played back in the lowest required playback capability is provided. Lowest playback capability means that the number of input channels, simultaneous decodings, and output channels are at their minimum values ​​(i.e., 1 channel), and the bitrate is the lowest (e.g., 128kbps), meaning the level is the lowest. Information may be added to the information table to indicate that the emergency audio asset has a higher priority than other audio assets. For example, the smallest component tag value may be described for the emergency audio asset. The receiving device 20 can select from among multiple audio assets that transmit playable audio, prioritizing those with smaller component tag values.

[0033] The receiving device 20 comprises a tuner 212, a demultiplexer 220, a selector 232, an audio decoder 234, a mixer 236, a video decoder 242, and a presentation processing unit 244. The receiving device 20 includes an operation input unit (not shown) that inputs operation signals based on user operation. The operation input unit may be, for example, an input interface that receives operation signals transmitted wirelessly from a control device (remote controller), or an input device that accepts user operation and generates operation signals, or a combination of either. The input device is not limited to dedicated components such as buttons, dials, and levers, but may also be general-purpose components such as touch sensors and mice. In this application, using the acquired operation signals as triggers or cues may be referred to as "in response to user operation."

[0034] The tuner 212 extracts a signal from the received signal input from the antenna that indicates the frequency component that tunes to the carrier frequency corresponding to the selected broadcast channel as a tuning signal (tuning). The antenna receives the broadcast wave arriving at its part and outputs the resulting electrical signal to the tuner 212 as a received signal. The receiving device 20 is equipped with a demodulator (Figure 9). The demodulator performs demodulation processing on the tuning signal extracted by the tuner 212 and converts it into multiplexed data.

[0035] The separator 220 detects an information table from the multiplexed data demodulated by the demodulator and separates individual assets from the multiplexed data according to the various descriptors described in the detected information table. The separator 220 outputs the video data that constitutes the video assets obtained by the separation to the video decoder 242. For audio assets, the separator 220 refers to the descriptors described in the information table and determines whether or not it is an AC-4 audio asset containing audio data encoded in AC-4 audio. If the separator 220 determines that the acquired audio asset is an AC-4 audio asset, and the audio decoder 234 has the capability to decode audio data based on AC-4 audio, it separates the audio data encoded in AC-4 audio from the separated audio asset.

[0036] Furthermore, even if the acquired audio asset is not determined to be an AC-4 audio asset, or if audio data encoded in a method other than AC-4 audio remains, the separator 220 separates the audio data related to each channel audio from the acquired audio asset. The separator 220 outputs the separated audio data to the selector 232, associating it with the component tag value that indicates the source audio asset.

[0037] The selector 232 selects audio assets from the audio data input from the separator 220 that the receiving device 20 is capable of playing, and rejects the other audio assets. The playback capability of the receiving device 20 may be indicated, for example, by the corresponding decoding method, level or audio mode, and stream format. The audio mode indicates the audio playback method, and the number of audio channels may differ depending on the playback method. If there are two or more types of playable audio assets selected, the selector 232 prioritizes selecting the emergency audio asset over the other audio assets. For example, the selector 232 selects the audio asset with the smallest corresponding component tag value. The selector 232 outputs the audio data constituting the selected audio asset to the audio decoder 234.

[0038] In the example shown in Figure 7, when OBA is provided in a sports broadcast, a broadcast signal containing an information table in which "0x0010" is described as the component tag value (component_tag) for the audio assets of the sports broadcast is transmitted from the transmitter 10 to the receiver 20. The separator 220 refers to the information table and separates the audio asset corresponding to this component tag value from the transmitted package. The separator 220 then selects the separated audio asset and outputs the audio data contained in the selected audio asset to the audio decoder 234.

[0039] In the example shown in Figure 8, when emergency audio is broadcast during a sports broadcast, the information table is updated to contain the component tag value "0x0011" for the sports broadcast audio asset and the component tag value "0x0010" for the emergency audio asset. The separator 220 refers to the information table and further separates the emergency audio asset corresponding to the component tag value. The selector 232 selects the emergency audio asset associated with the smallest component tag value "0x0010" from the separated audio assets and outputs the audio data contained in the selected audio asset to the audio decoder 234. As a result, the sports broadcast audio asset is no longer selected.

[0040] Furthermore, if there are two or more playable audio assets, the selector 232 may output asset notification information indicating each asset to the display processing unit 244 and display a settings screen including the asset notification information on the display 246. The selector 232 may also select one of the two or more playable audio data in response to user operation. The two or more playable audio assets may include audio assets related to normal OBA and emergency audio assets. This ensures that even when an emergency audio is automatically selected, the user has the opportunity to arbitrarily select one of the playable audio data.

[0041] Returning to Figure 3, the audio decoder 234 decodes the audio data input from the selector 232 and converts it into audio data representing an audio waveform. In decoding the audio data, the audio decoder 234 uses a decoding method corresponding to the encoding method used to encode the audio data. If the audio data to be decoded is audio data encoded in AC-4 audio, the audio decoder 234 outputs the converted audio data to the mixer 236. Audio data decoded in the AC-4 method includes audio data representing individual elemental sounds. If the audio data to be decoded is audio data encoded in a method other than AC-4, the audio decoder 234 outputs the converted audio data as output audio data to the speaker 238.

[0042] Mixer 236 adjusts the acoustic characteristics of the elemental audio indicated in the audio data input from audio decoder 234, and performs downmixing on the elemental audio after the acoustic characteristics have been adjusted. Mixer 236 corresponds to the function of the digital mixer described above. The downmixing process yields output audio data with a number of channels corresponding to the number of speakers 238. Mixer 236 may output object notification information, which allows for adjustment of acoustic characteristics, to the display processing unit 244, and display a setting screen including the object notification information on the display 246. Mixer 236 adjusts the acoustic characteristics instructed according to user operation. Mixer 236 outputs the generated output audio data to speaker 238. Furthermore, if no audio data is input to mixer 236, mixer 236 may stop outputting object notification information and stop displaying the settings screen on display 246. Cases where no audio data is input to mixer 236 may include the selection of an emergency audio asset.

[0043] Speaker 238 emits sound according to the output audio data input from the audio decoder 234 or mixer 236. The number of speakers 238 is not limited to one, but can be two or more. Each speaker corresponds to an audio channel, and output audio data for each audio channel is obtained from the audio decoder or mixer 236. In other words, the number of speakers 238 required may differ depending on the audio mode.

[0044] The video decoder 242 decodes the video data input from the separator 220 and outputs the decoded video data to the presentation processing unit 244. In decoding the video data, the video decoder 242 uses a decoding method that corresponds to the encoding method used to encode the video data.

[0045] The display processing unit 244 generates a display screen on which a broadcast screen showing the video indicated by the video data input from the video decoder 242 is placed, and outputs display data showing the generated display screen to the display 246. The display processing unit 244 may generate a setting screen for selecting one of several types of assets based on asset notification information input from the selector 232. The display processing unit 244 may generate a setting screen for adjusting the acoustic characteristics of individual element sounds based on object notification information input from the mixer 236. The display processing unit 244 may add the generated setting screen or other display information to the display screen. When the input of asset notification information from the selector 232 is stopped, the display processing unit 244 may stop its output by stopping the addition of the generated setting screen to the display screen. When the input of object notification information from the mixer 236 is stopped, the display processing unit 244 may also stop its output by stopping the addition of the generated setting screen to the display screen.

[0046] The presentation processing unit 244 may generate a display screen by arranging the application screen and the broadcast screen according to control information relating to application presentation. The application screen is generated when the processor of the receiving device 20 executes the application. The presentation processing unit 244 may perform a predetermined color space conversion process on the decoded video and adopt it as the broadcast screen. The separator 220 may separate one or both of the character superimposed data and subtitle data from the multiplexed data as character data, as an asset of media type other than audio and video. The presentation processing unit 244 decodes the separated character data and superimposes the resulting string onto the broadcast screen.

[0047] The display 246 displays the display screen indicated by the display data input from the display processing unit 244. In this invention, the execution of a process instructed by a command written in an application, utility, firmware, or other program may simply be referred to as "executing a program" or "program execution."

[0048] Next, control information transmitted in the broadcast signal will be described. In the MMT-TLV system, control information is transmitted superimposed on the TLV stream. The control information includes TLV-SI (TLV-Signaling Information) related to the TLV multiplexing system and MMT-SI (MMT-Signaling Information) related to MMT, which is a media transport system. An example of the structure of the protocol stack in which control information is placed in a system using MMT will be described. Figure 4 is a diagram showing an example of the structure of the protocol stack according to this embodiment. The example protocol stack has layers such as TMCC (Transmission and Multiplexing Configuration Control), time information, video data, audio data, subtitle data, MMT-SI, application, EPG (Electronic Programming Guide), and content download data. The code groups that constitute the video data and audio data of the broadcast program are divided and placed in an MFU (Media Fragment Unit) or MPU (Media Processing Unit). The MFU or MPU is placed in the MMTP payload of the MMTP (MMT Protocol) packet, and the MMTP packet is stored in an IP (Internet Protocol) packet and transmitted by the transmitting device 10. Data content, such as text data, is divided into predetermined data amounts and placed in MMTP packets by the transmitting device 10, then stored in IP packets and transmitted. When IP packets are transmitted using a broadcast transmission line, they are transmitted as TLV packets. One IP packet or one header-compressed IP packet is stored in one TLV packet.

[0049] The protocol stack used in broadcast system S1 has two types of control information configured: MMT-SI and TLV-SI. MMT-SI includes control information that indicates the structure of broadcast programs. MMT-SI has the format of an MMT control message, is placed in the MMTP payload of an MMT packet, and is transmitted by the transmitting device 10 in an IP packet. TLV-SI is control information related to the multiplexing of IP packets and transmits information for channel selection and information on the correspondence between IP addresses and broadcast services.

[0050] TMCC is control information inserted into a transmission frame and transmitted in a hierarchical modulation scheme that specifies the modulation scheme and error correction scheme for each signal unit (slot) on the transmission path. HEVC (High Efficiency Video Coding) is a representative type of video coding scheme. VVC (Versatile Video Coding) may also be used as a video coding scheme. AAC (Advanced Audio Coding), ALS (Audio Lossless Coding), and AC-4 are all audio coding schemes. UDP / IP (User Datagram Protocol / Internet Protocol) is one of the protocols used for communication. TLV is a data multiplexing method in which the encoding of data is specified by three elements: data type, length, and value.

[0051] MMT-SI includes various messages, tables, and descriptors. Messages include PA messages, M2 section messages, M2 short section messages, data transmission messages, and operator-defined messages. PA messages are messages that indicate the entry point of broadcast services, and PA messages include MPTs. MPTs are information tables that show the information that makes up the package, namely, a list of assets and their locations.

[0052] In MPT, each asset constitutes a unit with the same packet ID within a single IP data flow. In other words, an asset corresponds to a transmission unit such as video or audio multiplexed using the MPT method. Each asset is identified using a component tag (component_tag).

[0053] Next, an example of the MPT data structure will be described. Figure 5 is a diagram illustrating the MPT data structure according to this embodiment. The MPT has an MPT descriptor area (MPT_descriptors_byte, also called the MPT first loop) and an asset descriptor area (asset_descriptors_byte, also called the MPT second loop). The MPT descriptor area is the area where the MPT descriptors are described. The MPT descriptor area mainly contains control information related to the entire broadcast service or package. The asset descriptor area is the area where the descriptors for individual assets are described. The asset descriptor area contains parameters related to the presentation of individual assets. For audio assets, an MH-Audio_Component_Descriptor is described. The MH-Audio_Component_Descriptor contains the component tags of the asset, as illustrated in Figure 6. For video assets, an MH-Video_Component_Descriptor (not shown) is described. The component tags for video assets are described in the MH-Video Component Descriptor.

[0054] Furthermore, the MH-Audio component descriptor may also contain a code indicating the next-generation audio encoding scheme for the audio asset and the playback environment (level). In the example in Figure 6, "nga_type" may specify either AC-4 audio or MPEG-4 audio as the encoding scheme, and "nga_level" may specify the level. The separator 220 or selector 232 can determine whether or not it is receiving a program for which OBA is provided based on whether or not it has an audio asset for which AC-4 audio is specified as the encoding scheme.

[0055] Selector 232 can refer to the MH-Audio Component Descriptor described for each audio asset and identify the stream format, encoding scheme, and corresponding playback environment for that audio asset. The stream format is indicated by the stream type "stream_type". The encoding scheme may be indicated by the stream content identifier (stream_content) or by the next-generation audio type (nga_type) as described above. If both the stream content identifier and the next-generation audio type are described, selector 232 may prioritize applying the next-generation audio type. The playback environment may be represented by the audio mode indicated by the component type "component_type" or by the level as described above. If both the component type and the level are described, selector 232 may prioritize applying the level. Selector 232 can determine whether the identified stream format, encoding scheme, and playback environment are compatible with the audio decoder 234, whether they correspond to a decoding scheme that can be decoded, and whether the identified playback environment can be played back by the speaker 238 (and, if applicable, by the mixer 236). Selector 232 may include information on the encoding method and / or playback environment of a playable audio asset in the asset notification information, and display it on the settings screen.

[0056] The asset descriptor area of ​​an audio asset containing audio data encoded in AC-4 audio may also contain an MH-AC-4 audio descriptor (MG-AC-4_Audio_Descriptor). The MH-AC-4 audio descriptor may contain information about the playback environment, the types of individual elemental audios, or combinations thereof. The descriptor may also contain information about the types of adjustable acoustic characteristic parameters for each elemental audio, and their initial values ​​(default values). The mixer 236 can refer to the MH-AC-4 audio descriptor to identify the type of elemental audio, the adjustable acoustic characteristics, and the initial values. The mixer 236 can determine whether the audio decoder 234 can decode and whether the speaker 238 can play the audio in the described playback environment. The mixer 236 may include the type and adjustable acoustic characteristics of each identified elemental audio (object) in object notification information and display it on the settings screen.

[0057] Next, an example of the hardware configuration of the receiving device 20 according to this embodiment will be described. Figure 9 is a schematic block diagram showing an example of the hardware configuration of the receiving device 20 according to this embodiment. The receiving device 20 is composed of a tuner 212, demodulator 214, separator 220, selector 232, audio decoder 234, mixer 236, speaker 238, video decoder 242, presentation processing unit 244, display 246, input / output unit 252, auxiliary storage device 254, ROM (Read Only Memory) 256, RAM (Random Access Memory) 258, CPU (Central Processing Unit) 260, and communication unit 262. Note that components related to data processing, such as the separator 220, selector 232, audio decoder 234, video decoder 242, and presentation processing unit 244, may be implemented using dedicated hardware, or they may be implemented by the CPU 260 executing a predetermined program.

[0058] The tuner 212 receives the broadcast signal received by the antenna via the input terminal of the receiving device 20. The tuner 212 extracts the component that tunes to the carrier frequency corresponding to the selected broadcast channel and outputs a received signal indicating the extracted component to the demodulator 214.

[0059] The demodulator 214 demodulates the received signal input from the tuner 212 and converts it into a TLV stream that carries the multiplexed data. The demodulator 214 outputs the converted TLV stream to the separator 220.

[0060] The separator 220 performs TLV / MMT separation processing on the TLV stream input from the demodulator 214, separating the assets contained in the package from the various MMT messages and tables. The separator 220 refers to the information table and outputs the separated audio assets to the selector 232 and the video assets to the video decoder 242.

[0061] Selector 232 selects audio data from the audio assets input from separator 220 that can be decoded by audio decoder 234 and played back by speaker 238. If there are multiple types of selected audio data, selector 232 prioritizes selecting audio data related to audio assets with smaller component tag values ​​associated with that audio asset. Selector 232 may select one type of audio data from among multiple types in response to user operation. Selector 232 outputs the selected audio data to audio decoder 234. Selector 232 may output asset notification information indicating multiple types of assets to presentation processing unit 244, and cause presentation processing unit 244 to display a setting screen showing the asset notification information on display 246. Selector 232 may include information of the currently selected asset in the asset notification information and display it in a different manner (for example, brightness, color, etc., of text or background) than the unselected assets.

[0062] The audio decoder 234 decodes the audio data input from the selector 232 using a decoding method corresponding to the encoding method used to encode the audio data, and converts it into audio data representing an audio waveform. If the decoding method used is one that corresponds to AC-4 audio, the audio decoder 234 outputs the converted audio data to the mixer 236. If the decoding method used is one that corresponds to an encoding method other than AC-4 audio, the audio decoder 234 outputs the converted audio data as output audio data to the speaker 238.

[0063] Mixer 236 synthesizes the elemental audio components indicated in the audio data input from audio decoder 234 and performs downmixing. The number of elemental audio components may correspond to the number of input channels in one asset. In the downmixing process, mixer 236 adjusts the acoustic characteristics of each elemental audio component as instructed by the user, and mixes the adjusted elemental audio components to generate output audio data. Mixer 236 outputs the generated output audio data to speaker 238. The number of channels in the output audio data may correspond to the number of output channels, i.e., the number of speakers 238 used for playback.

[0064] The speaker 238 emits sound according to the output audio data input from the audio decoder 234 or mixer 236.

[0065] The video decoder 242 decodes the video data input from the separator 220 and outputs the decoded video data to the presentation processing unit 244. In decoding the video data, the video decoder 242 uses a decoding method that corresponds to the encoding method used to encode the video data.

[0066] The display processing unit 244 generates a display screen in which the broadcast screen shown in the video data input from the video decoder 242 is arranged, and outputs display data showing the generated display screen to the display 246. The display processing unit 244 may superimpose a settings screen, application screen, text overlay, or subtitles onto the display screen.

[0067] The display 246 displays a screen according to the display data input from the presentation processing unit 244.

[0068] The input / output unit 252 connects to other devices so that various types of data can be input and output via wired or wireless connections. The input / output unit 252 is, for example, an input / output interface.

[0069] The auxiliary storage device 254 stores various types of data in a read-write manner. The auxiliary storage device 254 may be, for example, an HDD (Hard-disk drive) or an SSD (Solid State Drive).

[0070] ROM256 permanently stores programs executed by CPU260, various parameter sets used in processing, and other related information.

[0071] RAM258 is the main memory used as a workspace for processing performed by the CPU260. RAM258 temporarily stores various parameter sets, input values, intermediate values, and output values ​​used in the processing.

[0072] The CPU 260 is a processor that implements and controls the functions of the receiving device 20 by executing a predetermined program. The CPU 260 and RAM 258 constitute the minimum hardware that forms the main computer system of the receiving device 20.

[0073] The communication unit 262 connects to other devices via a communication network, enabling it to send and receive various types of data by wire or wireless connection. The communication unit 262 includes, for example, a communication chip or a communication module.

[0074] Figure 9 illustrates a case where the receiving device 20 integrates a speaker 238 and a display 246, but it is not limited to this configuration. One or both of the speaker 238 and the display 246 may be omitted from the receiving device 20, and input / output may be made wireless or wired using the input / output unit 252 or the communication unit 262.

[0075] Next, an example of the hardware configuration of the transmitting device 10 according to this embodiment will be described. Figure 10 is a schematic block diagram showing an example of the hardware configuration of the transmitting device 10 according to this embodiment. The transmitting device 10 includes a content acquisition unit 112, a control information acquisition unit 132, a multiplexer 142, a modulator 144, and a transmitter 146.

[0076] The content acquisition unit 112 acquires packages that constitute the content of a broadcast program. Each package contains at least one audio asset and one video asset. The audio asset may contain audio data encoded using AC-4 audio, with one or more elemental audio related to the OBA being transmitted. Each package may contain multiple audio assets that differ in one or a combination of the stream format, encoding method, and playback environment (level). Multiple audio assets may include an emergency audio asset.

[0077] The control information acquisition unit 132 acquires control information related to the broadcast of the acquired package. The control information includes configuration information that shows the configuration of the package.

[0078] The multiplexer 142 receives control information from the control information acquisition unit 132 and acquires packages having the configuration indicated by the input control information from the content acquisition unit 112. The multiplexer 142 multiplexes the acquired packages and control information to generate a TLV stream that forms the multiplexed data. The TLV stream generated by the multiplexer 142 is output to the modulator 144.

[0079] The modulator 144 modulates the TLV stream input from the multiplexer 142, converts it into a broadcast signal, and outputs the converted broadcast signal to the transmitter 146.

[0080] The transmitter 146 sends the broadcast signal input from the modulator 144 to the broadcast transmission line.

[0081] The data processing components, such as the content acquisition unit 112, the control information acquisition unit 132, and the multiplexer 142, may be implemented using dedicated hardware, or they may be implemented by a processor such as a CPU executing a predetermined program.

[0082] Next, the reception process according to this embodiment will be described. Figure 11 is a flowchart illustrating the reception process according to this embodiment.

[0083] (Step S202) The separator 220 separates the MPT from the multiplexed data demodulated from the broadcasted received signal.

[0084] (Step S204) Selector 232 refers to the MPT and determines whether or not a broadcast program for which OBA is provided is being received by checking whether or not an audio asset with the encoding scheme AC-4 audio has been selected from the audio assets included in the package. If it is being received (Step S204 YES), proceed to step S206. If it is not being received (Step S204 NO), return to step S202.

[0085] (Step S206) Selector 232 refers to the MPT and determines whether the audio assets included in the package have been added. If they have been added (Step S206 YES), proceed to step S208. If they have not been added (Step S206 NO), return to step S202.

[0086] (Step S208) Selector 232 selects the added emergency audio asset and starts playing the audio data contained in the selected emergency audio asset.

[0087] (Step S210) Selector 232 refers to the MPT and determines whether the number of audio assets included in the package has decreased. If it has decreased (Step S210 YES), proceed to step S212. If it has not decreased (Step S210 NO), repeat step S210.

[0088] (Step S212) Selector 232 re-selects an audio asset related to the provision of OBA as an example of an audio asset that was selected before the provision of the emergency audio, in place of the emergency audio asset that is no longer being transmitted. The re-selected audio asset makes it possible to provide OBA again. After that, the process shown in Figure 11 is terminated.

[0089] <Second Embodiment> Next, a broadcasting system S1 according to the second embodiment will be described. The following description will mainly focus on the differences from the above embodiment. Procedures and configurations common to the above embodiment will be denoted by the same reference numerals, and unless otherwise specified, their descriptions will be used accordingly.

[0090] In the first embodiment, the selector 232 of the receiving device 20 was shown to monitor the number of audio assets included in the package by referring to an information table and selecting the audio asset corresponding to the smallest component tag value. By writing the smallest component tag value for emergency audio assets in the information table, the receiving device 20 could determine that emergency audio assets should be prioritized for selection. However, the receiving device 20 does not recognize that emergency audio assets are carrying emergency information. Furthermore, if the emergency is limited to a specific area, the emergency information is not necessarily useful for the entire area covered by the broadcast service.

[0091] Therefore, in this embodiment, an emergency news descriptor is included in the information table, and the component tag information of the audio asset is transmitted using the emergency news descriptor. The main use of the emergency news descriptor is to indicate to broadcast services that an emergency news bulletin is being broadcast. An emergency news bulletin is news that concerns the safety or security of the general public and is information that needs to be transmitted quickly. Emergency bulletins may be transmitted in the form of, for example, an earthquake early warning, breaking news, or a news flash.

[0092] The selector 232 of the receiving device 20 determines whether or not an emergency news descriptor is described in the transmitted information table. If an emergency news descriptor is described, the selector 232 extracts information about component tags from the emergency news descriptor. The selector 232 identifies the component tag value from the extracted information and can select the audio asset identified by the identified component tag value as an emergency audio asset. Therefore, even if the minimum component tag value is not assigned to the emergency audio asset, the audio of the normal broadcast program will switch to emergency audio.

[0093] Next, an example of the data structure of the emergency news descriptor according to this embodiment will be described. Figure 12 shows an example of the data structure of the emergency news descriptor according to this embodiment. The emergency news descriptor (Emergency_News_Descriptor) is set in the MPT descriptor area (MPT_descriptors_byte) in the MPT which forms the information table. The emergency news descriptor is provided with a 5-bit field for the emergency audio stream number (emergency_audio_stream_number). The emergency audio stream number is set to a value that is 10 (0x0010) smaller in hexadecimal than the component tag value. Selector 232 can determine that an asset is an emergency audio asset by detecting the emergency news descriptor from the asset descriptor of the asset described in the information table. Selector 232 determines the component tag value by adding 10 (0x0010) in hexadecimal to the emergency audio stream number described in the emergency news descriptor. Selector 232 selects an asset corresponding to a defined component tag value as an emergency audio asset and outputs the selected emergency audio asset to audio decoder 234.

[0094] As illustrated in Figure 13, each of the 32 component tag values ​​"0x0010" to "0x002F" corresponds to an emergency audio stream number "0x0000" to "0x001F". The range of these component tag values ​​corresponds to the range of component values ​​assigned to broadcast transmission audio as defined in the Advanced Broadband Satellite Digital Broadcasting Operation Regulations Technical Document ARIB TR-B29 Version 2.5 (Third Volume). The minimum value, "0x0010", is defined as being assigned to the default asset. Therefore, by assigning a component value other than the default asset to the emergency audio asset, it is possible to avoid conflicts with the default asset for broadcast programs. In other words, broadcasters can assign the minimum component tag value as the default asset to the asset most desired by the broadcaster or program producer when scheduling normal broadcast programs, without considering emergency broadcasts. Assigning the minimum component tag value ensures the possibility of receiving it with the highest priority. Furthermore, even during emergency broadcasts, in areas unaffected by the emergency, there is still room for the system to deselect emergency audio based on user input and prioritize playback of default assets.

[0095] Next, the reception process according to this embodiment will be described. Figure 14 is a flowchart of a first example of the reception process according to this embodiment. The process illustrated in Figure 14 has steps S202, S204, S206, S222, S224, S226 and S212. In step S206, if an audio asset is added (step S206 YES), the process proceeds to step S222.

[0096] (Step S222) Selector 232 determines whether there is an emergency news descriptor in the MPT descriptor area among the assets included in the package. If there is an emergency news descriptor (Step S222 YES), proceed to step S224. If there is no emergency news descriptor (Step S222 NO), return to step S202.

[0097] (Step S224) Selector 232 calculates a component tag value by adding the hexadecimal value "10" to the emergency audio stream number described in the emergency news descriptor. Selector 232 refers to the MH-Audio component descriptors located in the asset descriptor area and detects assets with component tag values ​​equal to the calculated component tag value as emergency audio assets. Selector 232 outputs the detected emergency audio assets to the audio decoder 234. As a result, the emergency audio transmitted by the emergency audio assets is played.

[0098] (Step S226) Selector 232 determines whether the emergency news descriptor has disappeared from the MPT descriptor area. If it is determined that it has disappeared (Step S226 YES), selector 232 determines that the broadcast of the emergency audio has ended, re-selects the audio asset related to the OBA as an example of an asset that was selected before the detection of the emergency audio asset, and proceeds to the process in step S212. If it is determined that it has not disappeared (Step S226 NO), the process in step S226 is repeated.

[0099] Next, another example of the reception processing according to this embodiment will be described. Figure 15 is a flowchart showing a second example of the reception processing according to this embodiment.

[0100] (Step S232) The operation input unit 216 receives user input and acquires an operation signal indicating the broadcast channel for receiving broadcast programs. The tuner 212 extracts a tuning signal corresponding to the broadcast channel instructed by the user from the received signal input from the antenna (channel selection). The demodulator 214 demodulates the extracted tuning signal and converts it into multiplexed data.

[0101] (Step S234) The selector 232 monitors the MPT separated from the multiplexed data modified by the separator 220 and determines whether the separated MPT has been updated. If it is determined that the MPT has been updated (Step S234 YES), the process in Step S238 is repeated. If it is determined that the MPT has not been updated (Step S234 NO), the process returns to Step S234. The selector 232 can, for example, compare the MPT acquired at the present time (sometimes called the current MPT in this application) with the MPT acquired immediately before (not acquired at the present time) and determine whether the MPT has been updated based on whether there is a difference between the two.

[0102] (Step S236) Selector 232 refers to the MPT to identify the component tag for each asset. Selector 232 sets a predetermined minimum value (e.g., 0x0010) for the component tag value i and checks the default asset, which is the audio asset corresponding to the set minimum value.

[0103] (Step S238) Selector 232 determines whether the component tag value i is less than or equal to a predetermined maximum value (for example, 0x002F). If it is determined to be less than or equal to the maximum value (Step S238 YES), the process proceeds to step S240. If it is determined to be greater than the maximum value (Step S238 NO), the process proceeds to step S246.

[0104] (Step S240) Selector 232 determines whether the asset indicated by the component tag value i is a stream (asset) that the receiver (receiving device 20) can play back. Selector 232 identifies the type of asset described in the MH-Audio component descriptor in which the component tag value i is described. Selector 232 identifies the encoding scheme by referring to either the stream content identifier (stream_content) or the next-generation audio type (nga_type). Selector 232 identifies the playback capability of its own device by referring to either the described component type (component_type) or level (nga_level). Selector 232 identifies the stream format (e.g., LATM / LOAS (Low-overhead Audio Transport Multiplex / Low Overhead Audio Stream) format) by referring to the stream type (stream_type). Selector 232 can refer to the pre-configured capability information of its own device and determine whether the identified encoding scheme, playback capability, and stream format correspond to the encoding scheme, playback capability, and stream format that its own device has processing capability for, respectively. If it is determined that playback is possible (step S240 YES), the process proceeds to step S242. If it is determined that playback is not possible (step S240 NO), selector 232 updates the component tag value i by adding 1 to the component tag value i at that point (increment). Then, the process returns to step S236.

[0105] (Step S242) Selector 232 identifies various operational information described in the MH-Audio Component Descriptor in which its component tag value i is described. Selector 232, for example, refers to the Simulcast Group Identifier (simulcast_group_tag) to determine whether simulcasting is present (i.e., whether the same audio content is transmitted using multiple different playback methods). Selector 232 refers to the Multilingual Flag (ES_multi_lingual_flag) to determine whether multilingual operation (i.e., audio multiplex broadcasting) is being performed. Selector 232 refers to the Language Codes (ISO_639_lsnguage_code, ISO_639_language_code_2) to identify the language of the audio to be broadcast.

[0106] (Step S244) The selector 232 stores the component tag value i and the identified asset type and operational information in memory (e.g., auxiliary storage device 254). A list of audio assets related to the broadcast program being received is formed in memory (listing). The generated list corresponds to the asset notification information described above. The selector 232 updates the component tag value i by adding 1 to the component tag value i at that time (incrementing). Then, the process returns to step S236.

[0107] (Step S246) Selector 232 determines whether an emergency news descriptor is described in the MPT. If it is described (Step S246 YES), proceed to step S248. If it is not described (Step S246 NO), proceed to step S252.

[0108] (Step S248) Selector 232 obtains the emergency audio stream number (emergency_audio_stream_number) from the emergency news descriptor.

[0109] (Step S250) Selector 232 selects the audio asset (stream) corresponding to the component tag value obtained by adding the hexadecimal value "10" (0x0010) to the acquired emergency audio stream number. Then proceed to step S254.

[0110] (Step S252) Selector 232 selects one asset (i.e., stream) from the list of playable audio assets stored in memory. Selector 232 allows the receiver (user) to make an arbitrary selection in response to an operation (manual selection). For example, selector 232 configures a setting screen that shows a list of audio asset types, outputs the configured setting screen to the presentation processing unit 244, and includes it in the display screen to be displayed on the display 246. Selector 232 selects the audio asset indicated by the operation signal input from the operation input unit. Unless otherwise specified, selector 232 selects the audio asset with the smallest component tag value from among the playable audio assets included in the list (automatic selection).

[0111] (Step S254) The selector 232 notifies the presentation processing unit 244 of the type of audio asset selected, i.e., information such as language, and has it displayed on the display screen on the display 246.

[0112] (Step S256) The selector 232 outputs the audio data contained in the selected audio asset to the audio decoder 234, causing the speaker 238 to play sound based on the audio data. The audio decoder 234 decodes the audio data input from the selector 232 and converts it into audio data that shows the audio waveform obtained by decoding. If the decoding method used is a decoding method that corresponds to AC-4 audio, the audio decoder 234 outputs the converted audio data to the speaker 238 as output audio data obtained via the mixer 236. If the decoding method used is a decoding method that corresponds to an audio encoding method other than AC-4 audio, the audio decoder 234 outputs the converted audio data to the speaker 238 as output audio data. The speaker 238 emits sound according to the output audio data input from the audio decoder 234 or the mixer 236. Then, the process returns to step S234.

[0113] As described above, the receiving device 20 according to this embodiment includes a receiving unit (e.g., tuner 212, demodulator 214) that receives multiplexed data from a broadcast, in which a package containing a plurality of assets and an information table indicating the configuration information of the package are multiplexed; a separation unit (e.g., separator 220) that separates the information table (e.g., MPT) from the multiplexed data; and a selection unit (e.g., selector 232) that selects a first audio asset containing object audio (e.g., element audio) from the package based on the information table. When the selection unit detects a second audio asset that does not contain object audio, it selects the detected second audio asset with priority over the first audio asset. The functions of the receiving device 20 may be implemented by executing a program on a computer. Furthermore, the broadcast system S1 according to this embodiment includes the above-described receiving device 20 and transmitting device 10. The transmitting device 10 includes a multiplexing unit (e.g., a multiplexer 142) that multiplexes a package and an information table showing the configuration information of the package to constitute multiplexed data, and a transmitting unit (e.g., a transmitter 146) that transmits the multiplexed data by broadcast.

[0114] In this configuration, when a second audio asset that does not contain object audio is detected while a first audio asset containing object audio is being received, the second audio asset is selected with priority over the first audio asset. Therefore, even if the output of the object audio transmitting the emergency audio is suppressed, the audio data of the second audio asset containing the emergency audio is decoded and presented. As a result, the receiver can more reliably access the audio of the emergency broadcast while the OBA is being provided.

[0115] The selection unit may also monitor the information table and detect a second audio asset based on the number of audio assets included in the package. With this configuration, as the number of audio assets increases, it becomes easy to determine whether to add a second audio asset separate from the first audio asset that is currently selected.

[0116] Furthermore, the information table shows the component tags for each asset, and the selection section may prioritize selecting audio assets with smaller component tag values ​​from among the playable audio assets when a package contains multiple audio assets. This configuration ensures that audio assets containing emergency audio are selected by associating them with the smallest component tag value.

[0117] The information table is an MMT package table (MPT), and if the MPT contains an emergency news descriptor, the selection unit may select the audio asset indicated by the emergency news descriptor as the second audio asset. With this configuration, regardless of the component tag value, the audio asset related to emergency audio can be selected as the second audio asset based on the emergency news descriptor detected from the MPT. Therefore, even if a broadcast program package contains multiple audio assets that are prioritized by their component tag values, emergency audio can be prioritized for playback.

[0118] When a second audio asset is detected, the selection unit may output asset notification information indicating both the first and second audio assets, and may select either the first or second audio asset depending on the user's input. In this configuration, while receiving the first audio asset, asset notification information indicating the second audio asset is output, thereby notifying the recipient of the reception of the second audio asset. Furthermore, by allowing the recipient to select either the first or second audio asset depending on the operation, even when an emergency audio message is selected, the recipient is given the opportunity to select the first audio asset according to their own wishes.

[0119] While embodiments of this invention have been described in detail above with reference to the drawings, the specific configurations are not limited to the embodiments described above, and include designs and the like that do not depart from the spirit of this invention. The configurations described in the embodiments described above can be combined arbitrarily. Furthermore, parts of each configuration may be omitted or modified. [Explanation of Symbols]

[0120] S1…Broadcasting system, 10…Transmitter, 20…Receiver, 30…Broadcasting station server equipment, 40…Operator server equipment, 112…Content acquisition unit, 132…Control information acquisition unit, 142…Multiplexer, 144…Modulator, 146…Transmitter, 212…Tuner, 214…Demodulator, 220…Separator, 232…Selector, 234…Audio decoder, 236…Mixer, 238…Speaker, 242…Video decoder, 244…Presentation processing unit, 246…Display, 252…Input / output unit, 254…Auxiliary storage device, 256…ROM, 258…RAM, 260…CPU, 262…Communication unit, Sa…Relay station

Claims

1. A receiving unit that receives multiplexed data via broadcast, which consists of a package containing multiple assets and an information table showing the configuration information of the package, A separation unit that separates the information table from the multiplexed data, The system includes a selection unit that selects a first audio asset, including object audio, from the package based on the aforementioned information table, The aforementioned selection unit is When a second audio asset that does not contain the object audio is detected, the second audio asset is selected with priority over the first audio asset. Receiving device.

2. The selection unit monitors the information table and detects the second audio asset based on the number of audio assets included in the package. The receiving device according to claim 1.

3. The aforementioned information table shows the component tags for each asset, When the package contains multiple audio assets, the selection unit prioritizes selecting audio assets with smaller component tag values ​​from among the playable audio assets. The receiving device according to claim 2.

4. The aforementioned information table is an MMT package table (MPT), When the aforementioned MPT includes an emergency news descriptor, The selection unit selects the audio asset indicated by the emergency news descriptor as the second audio asset. The receiving device according to claim 2.

5. The aforementioned selection unit is When the second audio asset is detected, asset notification information indicating the first audio asset and the second audio asset is output. Select either the first audio asset or the second audio asset depending on the operation. The receiving device according to claim 2.

6. A program for causing a computer to function as the receiving device described in claim 1.

7. A broadcasting system comprising a transmitting device and a receiving device as described in claim 1, The transmitting device is A multiplexing unit that multiplexes the package and an information table showing the configuration information of the package to constitute the multiplexed data, The system comprises a transmitting unit that transmits the multiplexed data via broadcast. Broadcasting system.

8. Multiplexed data, which consists of a package containing multiple assets and an information table showing the configuration information of the said package, is received via broadcast. The information table is separated from the multiplexed data, A receiving method for a receiving device that selects a first audio asset, including object audio, from the package based on the information table, The receiving device, When a second audio asset that does not contain the object audio is detected, the second audio asset is selected with priority over the first audio asset. Reception method.

Images