JP6679794B2 - Broadcast receiving device and broadcast receiving method - Google Patents

Description

  The present invention relates to a broadcast receiving device and a broadcast receiving method.

  In a digital television broadcasting system for advanced BS / advanced broadband CS broadcasting, MPEG4-AAC (Moving Picture Experts Group 4-Advanced Audio Coding) (1ch, 2ch, 5.1ch, 7.1ch, 22.2ch) is used as the Audio Stream profile. And MPEG4-ALS (Moving Picture Experts Group 4-Audio Lossless Coding) (2ch, 5.1ch) are planned to be adopted. As means for outputting these Audio Streams from the receiving device to external audio equipment (including AV amplifier, sound bar, etc.), optical cable / coaxial cable compliant with S / PDIF (Sony Philips Digital Interface) standard, or HDMI ( (Registered trademark) -Forum (High-Definition Multimedia Interface-Forum) standardized HDMI cable transmission. In both cases, the signal transmission method is standardized by IEC61937.

  However, the bit rate of Audio Stream that can be transmitted by the current S / PDIF standard is up to about 1.5 Mbps, and in the case of MPEG4-AAC, up to 7.1 ch can be transmitted by the current S / PDIF standard. However, 22.2 ch cannot transmit data due to insufficient bit rate. Therefore, we are revising IEC61937 and studying to double the clock frequency during transmission and extend the transmission rate up to approximately 3 Mbps. Furthermore, in the case of 5.1-ch of MPEG4-ALS, the maximum bit rate of Stream is about 7.3 Mbps, so we are studying to support transmission clock frequency up to 8x speed so that this can be transmitted.

ARIB STD-B63 Version 1.1 “Receiver Standard for Advanced Broadband Satellite Digital Broadcasting” Revised March 17, 2015, The Association of Radio Industries and Businesses ARIB STD-B60 1.0 version "Media Transport System Standard by MMT for Digital Broadcasting" formulated on July 31, 2014, Japan Association of Radio Industries and Businesses

  By the way, when the doubling mode and the octupling mode of the transmission clock are defined in the above IEC61937, it becomes possible to manufacture a broadcast receiving device and an audio device capable of transmitting up to MPEG4-ALS 5.1ch according to the standard. However, in order to operate the transmission clock at 2x speed or 8x speed, it is necessary to use dedicated parts, etc., which increases the cost of the product.

  Also, considering that most audio is MPEG4-AAC 2ch or 5.1ch in actual broadcasting, in the case of cost-effective audio equipment, up to 1x speed that can support 1.5 Mbps, which is equivalent to the conventional one, is possible. It is desirable to distinguish such that only high-end models that support MPEG4-AAC 22.2ch or MPEG4-ALS support up to 2x speed or 8x speed. However, when an audio device is connected to the receiving device with an optical cable or a coaxial cable, there is a means for the receiving device to know how many speeds the connected audio device supports (which profile it supports). Absent. Therefore, unless some setting is made by the user's operation on the receiving device side, the double speed mode sound is output to an audio device that does not support the double speed mode sound, and there is a problem that no sound is produced during a certain broadcast program. Will occur.

  That is, in a broadcast receiving apparatus that receives a broadcast in which the first audio signal and the second audio signal are selectively transmitted and outputs the received audio signal to an externally connected audio device, There are a first transmission clock frequency and a second transmission clock frequency as a transmission clock frequency of the audio signal transmission between the two, and the first audio signal can be transmitted at both the first transmission clock frequency and the second transmission clock frequency. And when the second audio signal can be transmitted only at the second transmission clock frequency, the audio signal is output at the second transmission clock frequency to the audio device that does not support the second transmission clock frequency. There is a problem that no sound is produced.

  The object of this embodiment is to have a first transmission clock frequency and a second transmission clock frequency as transmission clock frequencies for audio signal transmission with an externally connected audio device, and the first audio signal is transmitted by the first transmission clock frequency. Suitable for the corresponding transmission clock frequency of the connected audio device when the second audio signal can be transmitted at both the clock frequency and the second transmission clock frequency and the second audio signal can be transmitted only at the second transmission clock frequency. It is an object of the present invention to provide a broadcast receiving apparatus and a broadcast receiving method capable of outputting an audio signal received in a form.

  The embodiment is a broadcast receiving apparatus for receiving a broadcast in which a first audio signal and a second audio signal are selectively transmitted and outputting the received audio signal to an externally connected audio device, wherein the external connection There are a first transmission clock frequency and a second transmission clock frequency as transmission clock frequencies for audio signal transmission with the audio device, and the first audio signal has a first transmission clock frequency and a second transmission clock frequency. And the second audio signal can be transmitted only at the second transmission clock frequency, and when switching between the first audio signal and the second audio signal during broadcasting, the second audio signal can be transmitted in advance. When the audio switching information is notified, the control unit causes the audio device to operate in the first mode in which only the first transmission clock frequency is supported, the first transmission clock frequency, and the second mode. Classified into the second mode corresponding to both the transmission clock frequency, and a control unit for determining the transmission clock frequency based on the voice switching information. When the connected audio device is in the first mode, the control unit receives the preceding audio signal as the first audio signal and the next received audio signal as the second audio signal. In this case, the preceding first audio signal is output at the first transmission clock frequency, and while the output of the audio signal is stopped during the switching period, the transmission clock of the first transmission clock frequency is used as the audio device. And outputs another audio signal at the first transmission clock frequency by selecting another second audio signal that can be transmitted at the first transmission clock frequency in the signal received next from the broadcast. And the connected audio device is in the second mode, the received preceding audio signal is the first audio signal and the next received audio signal is the second audio signal. In this case, the preceding first audio signal is output at the second transmission clock frequency, and while the output of the audio signal is stopped during the switching period, the transmission clock having the second transmission clock frequency is used as the audio signal. The second audio signal output to the device and then received is controlled to be output at the second transmission clock frequency.

FIG. 1 is a block diagram showing the configuration of a broadcast receiving device in advanced BS / advanced broadband CS broadcasting according to an embodiment. FIG. 3 is a block diagram for explaining switching of audio profiles when the broadcast receiving apparatus shown in FIG. 1 and an AV amplifier are connected. The figure which shows the operation | movement at the time of receiving the broadcast which audio assets (audio mode) change from AAC 2ch to ALS 2ch in the broadcast receiving apparatus and external AV amplifier in a conventional system. FIG. 10 is a diagram showing an operation when a broadcast in which the audio mode is changed from MPEG4-AAC 2ch to MPEG4-AAC 5.1ch is received by the conventional broadcast receiving device and the external AV amplifier. FIG. 10 is a diagram showing an operation when a broadcast in which the audio mode is changed from MPEG4-AAC 2ch to MPEG4-AAC 22.2ch is received in the conventional broadcast receiving device and the external AV amplifier. The figure which shows operation | movement at the time of receiving the broadcast which changes from AAC 2ch to AAC 22.2ch, when a profile is B connection mode in the broadcast receiving apparatus shown in FIG. The figure which shows the operation | movement at the time of receiving the broadcast which changes from AAC 2ch to AAC 22.2ch, when a profile is A connection mode in the broadcast receiving apparatus shown in FIG. 3 is a flowchart for explaining pre-mode setting of a profile in the broadcast receiving device shown in FIG. 1. 3 is a flowchart for explaining a switching process at the time of receiving a broadcast in the broadcast receiving device shown in FIG. 1.

  An embodiment of the present invention will be described below with reference to the drawings.

  The broadcast receiving apparatus according to the embodiment will be described below with reference to FIGS. 1 to 9.

  FIG. 1 is a block diagram showing a configuration of a broadcast receiving device 1 in advanced BS / advanced broadband CS broadcasting as an embodiment. This broadcast receiving device receives a received signal of a broadcast wave obtained by a reception antenna (not shown), demodulates a TLV stream by performing demodulation processing and error correction decoding processing in a demodulation unit 11, and TLV / MMT separation unit 12 The video stream and audio stream are separated from this TLV stream by.

  The TLV / MMT separation unit 12 separates a TLV (Type Length Value) packet and an MMT (MPEG Media Transport) packet from the audio stream and sends them to the audio selection control unit 13. Based on the TLV information of the TLV packet and the MMT information of the MMT packet, the audio selection control unit 13 selects one asset suitable for the AV amplifier 2 of the output destination from a plurality of audio assets, and selects the asset as an internal reproduction system. Output to each external output system.

  In the internal playback system, the decoder 14 decodes the selected audio asset, and if the decoded output is 5.1ch PCM data, the downmixer (DMIX) unit 15 converts it to 2ch PCM data and sends it to the switching unit 16. If it is 2ch PCM data, it is sent directly to the switching unit 16. Based on an instruction from the audio selection control unit 13, the switching unit 16 selects either 2ch from the down mixer unit 15 or 2ch directly supplied from the decoder 14 at the input, and outputs at the internal reproduction system or the external device. Select one of the output systems.

  2ch PCM data selectively output to the internal reproduction system by the switching unit 16 is converted into an analog audio signal by a DAC (Digital-Analog Converter) 17 and sent to an audio output unit 18 by an internal amplifier and a speaker for sound reproduction. To be done. The 2ch PCM data selectively output to the external output system is sent to the external output interface (I / F) 19. The external output interface 19 includes an HDMI output terminal, an S / PDIF optical digital audio output terminal, and an S / PDIF coaxial digital audio output terminal, and an external AV amplifier 2, an HDMI cable, an S / PDIF optical digital cable, and an S / PDIF optical digital cable, respectively. It can be connected by a PDIF coaxial digital cable, and outputs the audio asset selected by the audio selection control unit 13 to the externally connected AV amplifier 2. When the corresponding audio mode information of the externally connected AV amplifier 2 is not obtained, the 2ch PCM data from the switching unit 16 is selected and output to the AV amplifier 2.

  Here, in the external output interface 19, when the corresponding audio mode information is obtained when the AV amplifier 2 is connected, the information is sent to the audio selection control unit 13. When the corresponding audio mode information of the connected AV amplifier 2 is obtained from the external output interface 18, the audio selection control unit 13 registers the information, and when the audio asset of the corresponding audio mode arrives. , Set to switch to output the audio asset.

  On the other hand, the video stream obtained by the demodulation unit 11 is sent to the video processing unit 1A. The video processing unit 1A generates a video signal of a predetermined resolution from the input video stream and sends it to the display device 3 for display. Here, when the corresponding audio mode of the connected AV amplifier 2 cannot be registered and set, the audio selection control unit 13 displays a display on the GUI (Graphical User Interface) display unit 1B for prompting an input operation for mode selection. Send instructions to do so. In response to the instruction, the GUI display unit 1B causes the display device 3 to display the mode selection input operation screen through the video processing unit 1A. When the user sees the screen and operates the operation input unit 1C to select the corresponding audio mode of the AV amplifier 2, the audio selection control unit 13 registers and sets the corresponding audio mode of the connected AV amplifier 2. be able to.

  FIG. 2 is a conceptual diagram for explaining a process of transmitting an audio asset by connecting the external AV amplifier 2 to the broadcast receiving device 1. In FIG. 2, the connection between the receiving device 1 and the external AV amplifier 2 is performed by any one of an HDMI cable, an S / PDIF optical digital cable, and an S / PDIF coaxial digital cable.

  First, when the receiving device 1 is in the form of a set top box (STB), the HDMI output terminal of the receiving device 1 and the HDMI input terminal of the external AV amplifier 2 are connected by an HDMI cable. As a result, the audio signal is transmitted from the receiving device 1 to the external AV amplifier 2 together with the video signal. On the other hand, when the receiving device 1 is in the form of a TV, the HDMI output terminal of the external AV amplifier 2 is used for the purpose of inputting the video / audio signals reproduced by the external AV amplifier 2 to the receiving device (TV) 1. Connect the HDMI input terminal of the receiver (TV) 1 with an HDMI cable. In this case, by using the function (HDMI-ARC: Audio Return Channel) of transmitting only the audio signal from the receiving device (TV) 1 to the external AV amplifier 2 on the HDMI cable, the audio of the receiving device (TV) The signal can be transmitted to the external AV amplifier 2. The television-type receiving device 1 may be provided with an HDMI output terminal, and may be provided with a function of transmitting video / audio signals to the HDMI input terminal of the external AV amplifier 2.

  In the case of the connection using the S / PDIF optical digital cable or the S / PDIF coaxial digital cable, the digital audio output terminal of the receiving device 1 and the optical or coaxial digital audio input terminal of the external AV amplifier 2 are connected.

  Here, in any connection of HDMI, HDMI-ARC and S / PDIF, the audio output from the receiving device 1 to the external AV amplifier 2 is only one audio asset. When receiving a broadcast including a plurality of audio assets, the receiving device 1 selects and outputs one audio asset to be output to the external AV amplifier 2.

  Hereinafter, the connection with the external AV amplifier 2 and the processing required in the receiving device 1 will be described.

As shown in FIG. 2, the receiving device 1 receives a broadcast wave (TLV stream) including a plurality of audio streams (maximum audio asset number 4). For example, in advanced broadband CS broadcasting, 7 types of audio modes can be operated (note that in advanced BS digital broadcasting, AAC 1.0ch is not used, 6 types). Of these, if you want to broadcast audio modes other than AAC 1.0ch (not operated in advanced BS), AAC 2.0ch, and AAC 5.1ch, which are required to be played by the receiving device 1 independently, simulcast Audio is broadcast at the same time. Table 1 shows an example of a combination of audio modes and simul audio in broadcasting.

  The receiving device 1 selects one asset to be output from such a plurality of audio assets and outputs it to the external AV amplifier 2. The asset to be output may be arbitrarily selected by the user, or may be automatically selected when the audio mode compatible with the external AV amplifier 2 is known (set in advance on the receiving device 1 side). In this case, as in the case of reproduction on the main body of the receiving device 1, the asset with a small component tag value is prioritized. Further, a function of decoding the audio stream in the receiving device 1 and outputting it to the external AV amplifier 2 by linear PCM may be provided.

  The audio modes to be output to the outside are a combination according to the support status of the output destination device.

The audio mode and switching operation in stream output will be described.
First, the method of stream output to S / PDIF and HDMI is specified by IEC60958 and IEC61937. When outputting each audio mode used in advanced BS broadcasting / advanced broadband CS broadcasting, it is output according to the regulations in Table 2.

  When transmitting AAC 22.2 ch and ALS audio, the bit rate of the signal exceeds the range that can be transmitted at the IEC60958 frame rate of 48 kHz, so it is necessary to expand the frame rate to double speed or more. Currently, we are preparing to revise the standards of IEC60958 and IEC61937 corresponding to this.

  As an operation example when outputting a broadcast whose audio mode changes to the external AV amplifier 2, the receiving apparatus 1 and the external AV amplifier 2 when receiving a broadcast whose audio mode changes from MPEG4-AAC 2ch to MPEG4-ALS 2ch The operation of is shown in FIG.

  The receiving device 1 receives the AAC 2ch asset that is the preceding voice (FIG. 3A) and outputs it to the S / PDIF at a frame rate of 48 kHz (FIG. 3B). The external AV amplifier 2 receives this stream, decodes it, and outputs it to the speaker (FIG. 3 (c)). When the preceding audio asset of the broadcast stops in this state (Fig. 3 (a)), the receiving device 1 outputs a NULL data stream to S / PDIF for 50msec or more according to IEC60958-1 (Fig. 3 (b)), and then S / Stops output to PDIF. With this NULL data stream, the external AV amplifier 2 discharges the audio stream accumulated in the buffer.

  When the receiving device 1 receives the ALS 2ch asset that is the subsequent audio (FIG. 3A), the receiving device 1 changes the S / PDIF frame rate to 96 kHz and outputs the ALS 2ch stream (see FIG. 3 ( b)). The external AV amplifier 2 that has received such a stream that changes on S / PDIF performs resynchronization processing by the PLL circuit with respect to changes in the frame rate. After that, the format of the audio stream is detected, the audio decoder is switched from AAC to ALS, and the subsequent audio is output from the speaker after the delay time of ALS decoding (FIG. 3 (c)).

  Further, in FIGS. 4 and 5, in the advanced BS / advanced broadband CS digital broadcasting, when a stream in which the audio mode changes is broadcast, the change of the audio mode in the broadcast signal and the S / PDIF from the receiving device 1 are shown. 3 shows the relationship between the signal output from the AV amplifier 2 and the audio data output from the AV amplifier 2.

  FIG. 4 shows the relationship when the audio mode changes from MPEG4-AAC 2ch to MPEG4-AAC 5.1ch. Receiving apparatus 1 which has received AAC 2ch from the broadcast signal outputs the AAC 2ch audio stream to S / PDIF at a transmission clock of 48kHz (1x speed). Also, in broadcasting, an MPT that notifies the change of the audio mode is transmitted about 100 msec before the audio mode changes.

  When the receiving device 1 looks at the contents of the MPT and finds that the audio changes from AAC 2ch to 5.1ch, it stops the output of the audio stream to S / PDIF. However, since the succeeding sound is 5.1ch and it is known that the same 48kHz transmission clock can be transmitted, the transmission clock continues to be output. After that, when the subsequent AAC 5.1ch audio stream is received, the stream is output to S / PDIF.

  The AV amplifier 2 that receives the signal from the S / PDIF outputs the AAC 2ch sound to the speaker while the AAC 2ch sound is being input, and stops the audio output when the no sound section is entered. Next, when an audio signal is input, a process of detecting what the audio is is performed, and when it is determined that the AAC is 5.1ch, it is output to the speaker.

  On the other hand, FIG. 5 shows a case where the audio mode changes from MPEG4-AAC 2ch to MPEG4-AAC 22.2ch. The difference from the case of FIG. 4 is that MPEG4-AAC 22.2 ch cannot transmit at a bit rate when the S / PDIF transmission clock is 48 kHz, and it is necessary to switch the transmission clock to 96 kHz (double speed). .

  Receiving the change in the audio mode by updating the MPT, the receiving device 1 stops the S / PDIF AAC 2ch audio output when it knows that the following audio is MPEG4-AAC 22.2ch that requires transmission at 96kHz. , After that, the output of 48kHz transmission clock is also stopped. After that, the audioless data of the transmission clock of 96kHz is output to S / PDIF, and when the 22.2ch audio stream is received, the audio is output to S / PDIF.

  Upon receiving the signal from the S / PDIF, the AV amplifier 2 receives the signal of the 96 kHz transmission clock after the AAC 2ch 48 kHz signal is cut off, and then synchronizes with the receiving device 1 at the frequency of 96 kHz by the PLL. I do. After the time required for this synchronization (about 200 msec) has passed, the audio signal is received and the sound is output to the speaker after understanding that it is AAC 22.2 ch. In this way, when the audio mode changes with different transmission clocks occur, there is a problem that the time required for sound output becomes long. As shown in FIG. 3, when switching the audio mode from MPEG4-AAC 2ch to MPEG4-ALS, since the transmission clock frequency is different, the same problem occurs.

As mentioned in the subject, the audio mode has been expanded in advanced BS broadcasting. As a result, there has been a voice mode in which the transmission clock frequency defined by the conventional S / PDIF standard does not allow transmission due to insufficient transmission rate. For this reason, the S / PDIF standard is being revised to extend the S / PDIF standard and enable high-speed transmission. Table 3 shows the relationship between the audio mode and the transmission clock frequency in S / PDIF.

  As an AV amplifier (including a device such as a sound bar) 2 compatible with advanced BS broadcasting, it is not necessary to receive and output all audio modes defined in the standard as shown in Table 3, AAC 1ch / 2ch It is possible to commercialize products that support only /5.1ch. In this case, the S / PDIF transmission clock frequency only needs to be compatible with 48 kHz.

  On the other hand, when the AV amplifier 2 is compatible with MPEG4-AAC 22.2 ch, the S / PDIF transmission clock frequency is compatible with both 48 kHz and 96 kHz. When the AV amplifier 2 supports MPEG4-ALS 5.1ch, it is necessary to support a transmission clock frequency of 384kHz.

In order to convey these distinctions to general consumers in an easy-to-understand manner, in this embodiment, AV amplifier products are classified into three profiles as shown in Table 4.

  On the other hand, the broadcasting station switches the audio mode of the audio stream during broadcasting and sends it out. For example, the main program is transmitted in MPEG4-AAC 5.1ch, and the CM part is transmitted in MPEG4-AAC 2ch.

  In advanced BS broadcasting, when such an audio stream is switched, the MPT is updated 100 msec before the switching to notify the receiving device 1 in advance that the audio stream will be switched.

  When the receiving device (TV) 1 that receives such a broadcast outputs sound from the built-in speaker, if the switching of the audio mode is known in advance by MPT update, the receiving device (TV) 1 first outputs the preceding side audio. Is muted to prepare for switching, the decoder mode is changed according to the audio mode of the subsequent audio stream, and when the subsequent audio is received, the subsequent audio is output to the speaker.

  On the other hand, when the audio stream is output from the receiving device (TV) 1 to the AV amplifier 2 and is output to the speaker via the AV amplifier 2, as shown in FIG. MPEG4-AAC 2ch) is output to S / PDIF. When the switching of the audio mode is detected by the MPT update, the output of the preceding audio to S / PDIF is stopped. However, the S / PDIF transmission clock continues to output at 48 kHz. Upon receiving the subsequent audio (MPEG4-AAC 5.1ch), the receiving device (TV) 1 outputs the subsequent audio stream to S / PDIF.

  Here, the S / PDIF has no means for transmitting information other than the audio stream from the receiving device (TV) 1 to the AV amplifier 2. Therefore, the AV amplifier 2 confirms the content of the received audio stream each time the audio mode is switched, and detects the change from AAC 2ch to AAC 5.1ch. For this reason, the following sound is output from the speaker after a certain time delay from the point where the stream on S / PDIF changed to AAC 5.1ch. This time is a time for the AV amplifier 2 to detect the audio mode switching.

  The above example describes the case where the change from MPEG4-AAC 2ch to MPEG4-AAC 5.1ch is made within the range of audio modes that can be transmitted at the S / PDIF transmission clock frequency of 48kHz. . FIG. 5 shows audio mode switching that requires switching from MPEG4-AAC 2ch to MPEG4-AAC 22.2ch to different transmission clock frequencies.

  Receiving the MPEG4-AAC 2ch audio that is the preceding audio, the receiving device (TV) 1 transmits the AAC 2ch stream at a transmission clock frequency of 48kHz when outputting the audio stream to S / PDIF. The receiver (TV) 1, which has recognized that the subsequent audio is MPEG4-AAC 22.2 ch by updating the MPT, first stops the transmission of the preceding audio. Next, the succeeding voice is in a voice mode that can be transmitted only with a clock of 96 kHz, so the transmission clock of 48 kHz is also stopped, and subsequently the transmission clock of 96 kHz is output. After that, when the subsequent audio is received, the audio stream of MPEG4-AAC 22.2 ch is transmitted at the clock of 96 kHz.

  On the other hand, from the viewpoint of the AV amplifier 2 side that receives this audio stream, the audio stream is first stopped and then the transmission clock of 48 kHz is also stopped while the preceding audio of MPEG4-AAC 2ch 48 kHz is being output. Next, the 96kHz transmission clock will be input via S / PDIF. Since the frequency of the transmission clock for communication has changed, the PLL circuit synchronizes the transmission clocks of the receiver (TV) 1 and the AV amplifier 2.

  When the communication path between the receiving device (TV) 1 and the AV amplifier 2 is synchronized, the audio stream can be received again via S / PDIF, the audio mode of the received audio stream is detected, and it is sent to the speaker. The sound is output. The time (PLL lock time) required for this PLL synchronization processing is expected to be relatively long, about 200 msec. Therefore, there is a problem in that the beginning portion of the following voice is missing.

  In order to avoid this problem, the receiving device (TV) 1 belongs to which profile in Table 4 which transmission clock frequency the AV amplifier 2 connected to the receiving device (TV) 1 can handle. Whether the AV amplifier is connected is stored as the profile connection mode.

  If an HDMI cable is used for the connection between the receiver (TV) 1 and the AV amplifier 2, the HDMI EDID (Extended Display Identificaiton Data) or HDMI-CEC (High Definition Multimedia Interface-Consumer Electronics Control) The receiving device (TV) 1 determines which profile the AV amplifier 2 belongs to based on the information that can be acquired, and stores the connection mode of the profile. For example, when an AV amplifier capable of supporting only MPEG2-AAC 2ch / 5.1ch is connected, the receiving device (TV) 1 stores and sets "Profile-A connection mode". When an AV amplifier capable of supporting MPEG2-AAC 2ch / 5.1ch / 22.2ch is connected, the receiving device (TV) 1 stores and sets the "Profile-B connection mode".

  On the other hand, when the connection between the receiving device (TV) 1 and the AV amplifier 2 is the S / PDIF optical cable or the coaxial cable, the receiving device (TV) 1 cannot acquire the information about the AV amplifier 2. For this reason, a menu for inputting the “profile of the connected AV amplifier” is created on the GUI of the receiving device (TV) 1 and the user is prompted to input it.

  By providing the receiving device (TV) 1 with the function of storing and setting the “profile connection mode” indicating which profile the AV amplifier 2 connected to the receiving device (TV) 1 belongs to, the receiving device (TV) 1 The audio stream output from S to PDIF is as shown in FIGS. FIGS. 6 and 7 show signals output from the receiving apparatus (TV) 1 to S / PDIF for each mode when receiving a broadcast in which the audio stream changes from MPEG4-AAC 2ch to MPEG4-AAC 22.2ch. It is a figure.

  FIG. 6 is a diagram when a Profile-B AV amplifier capable of handling AAC 22.2 ch is connected. The receiving device (TV) 1 set to “Profile-B connection mode” dares to output 96-kHz even if it is a stream of AAC 2ch that is originally 48 kHz when outputting MPEG4-AAC 2ch audio to S / PDIF. To output to S / PDIF. After that, even if audio switching to MPEG4-AAC 22.2ch occurs, it becomes possible to switch only the audio stream while keeping the transmission clock at 96kHz. As a result, the PLL lock time as shown in FIG. 5 becomes unnecessary, and the head loss of the sound at the switching point from AAC 2ch to 22.2ch can be reduced.

  On the other hand, FIG. 7 is a diagram when a Profile-A AV amplifier that cannot handle MPEG4-AAC 22.2 ch is connected. The receiving device (TV) 1 set to “Profile-A connection mode” cannot output a clock other than 48kHz to the AV amplifier of Profile-A when outputting MPEG4-AAC 2ch audio to S / PDIF. Since it is an output, the S / PDIF transmission clock is set to 48 kHz and output.

  For advanced BS broadcasting, the only audio decoder that the receiver must have is MPEG4-AAC 1ch / 2ch / 5.1ch, and other options are optional. Therefore, when broadcasting audio of AAC 22.2ch or MPEG4-ALS, audio of AAC 2ch or 5.1ch is always broadcast as simulcast.

  Profile-A AV amplifier cannot handle AAC 22.2ch audio. For this reason, the receiving device (TV) 1 that understands that audio switching to MPEG4-AAC 22.2ch will occur due to MPT update will output simulcast audio of AAC 2ch or 5.1ch that can be handled by the Profile-A AV amplifier. It searches from the broadcast signal and outputs the audio to S / PDIF with the transmission clock of 48 kHz. In this case, since the AV amplifier 2 receives a stream in which the mode does not change, that is, MPEG4-AAC 2ch for both the preceding audio and the subsequent audio, the subsequent audio can be output without requiring the audio mode detection time.

  In this way, when the connection between the receiving device (TV) 1 and the AV amplifier 2 is the S / PDIF optical cable or the coaxial cable, the receiving device (TV) 1 previously detects the audio mode that can be received by the AV amplifier 2. It is not possible to know automatically, but by registering the “Profile-A connection mode” in the GUI in advance by the user, it is necessary to output to the AV amplifier 2 a stream that can always play sound. You can

  MPEG4-AAC 22.2ch of this embodiment can be read as MPEG4-ALS 2ch. When handling MPEG4-ALS 5.1ch, a third profile and mode called Profile-C will be added.

  The above control processing is performed by the voice selection control unit 13 shown in FIG. A concrete procedure of processing in the voice selection control unit 13 is shown in FIGS. 8 and 9.

  FIG. 8 is a flowchart showing the procedure of voice mode registration setting processing. First, in the connection of the external AV amplifier 2, it is judged whether or not it is the connection by the HDMI cable (step S1), and if it is not the HDMI connection (NO), the GUI display (step S2) allows the user to select the profiles A to C. Is performed (step S3), and the selected profile is registered and set (step S4).

  In step S1, if the connection is HDMI (YES), it is determined whether EDID is available through the HDMI cable (step S5). If EDID is available (YES), EDID is acquired (step S6). Then, the physical address of the device is specified from the EDID to determine a compatible profile (step S7), and the process proceeds to step S4 to register and set the profile.

  If the EDID is not obtained in step S5 (NO), the HDMI-CEC command is obtained (step S8), the compatible profile is determined from the HDMI-CEC command (step S9), and the process proceeds to step S4. Migrate and register and set the profile.

  FIG. 9 is a flowchart showing the procedure of processing after the voice mode registration setting is made during S / PDIF connection as an example. First, when MPT is detected during reception of an audio stream (steps S11 and S12), the registered profile of the AV amplifier 2 is determined (step S13), and if the profile connection mode is A, the clock speed is set to 48 kHz (step S14). ), If B, the clock speed is set to 96 kHz (step S15), and if C, the clock speed is set to 384 kHz (step S16).

  Here, it is determined whether or not the double speed mode (96 kHz, 384 kHz) is selected in the above clock setting (step S17), and if it is not the double speed mode, it is converted to the 1 × 48 kHz voice mode (step S18). To the S / PDIF in the corresponding audio mode (step S19).

  As described above, in the broadcast receiving apparatus according to the present embodiment, when the non-double speed mode and the double speed mode audio are mixedly broadcast, the connected audio device does not support the audio mode of the double speed mode profile. In this case, when switching to the voice in the double speed mode, the voice can be converted into the voice in the non-double speed mode and output.

  Also, when the connected audio device also supports double speed mode, the audio mode of the corresponding profile is grasped in advance and the clock is set not to be changed before and after the audio mode switching. The head loss of the output voice can be extremely reduced.

  Further, even when it is not possible to grasp in advance the audio mode support status of the AV amplifier, the user can select the audio to be output by designating and inputting the mode through the GUI.

  Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.

  DESCRIPTION OF SYMBOLS 1 ... Broadcast receiving device, 11 ... Demodulation part, 12 ... TLV / MMT separation part, 13 ... Audio selection control part, 14 ... Decoder, 15 ... DMIX part, 16 ... Switching part, 17 ... DAC, 18 ... Audio output part, 19 ... External output interface, 1A ... Image processing section, 1B ... GUI display section, 1C ... Operation input section, 2 ... AV amplifier, 3 ... Display device.

Claims (14)

A broadcast receiving apparatus for receiving a broadcast in which a first audio signal and a second audio signal are selectively transmitted and outputting the received audio signal to an externally connected audio device,
There are a first transmission clock frequency and a second transmission clock frequency as transmission clock frequencies for audio signal transmission with the externally connected audio device, and the first audio signal has a first transmission clock frequency and a second transmission clock frequency. It is possible to transmit at both of the transmission clock frequencies, the second audio signal can be transmitted only at the second transmission clock frequency, and switching between the first audio signal and the second audio signal during broadcasting. If there is a notification of voice switching information in advance,
Classifying the audio device into a first mode corresponding only to the first transmission clock frequency and a second mode corresponding to both the first transmission clock frequency and the second transmission clock frequency; A control unit that determines the transmission clock frequency based on the voice switching information,
The control unit is
When the connected audio device is in the first mode, the received preceding audio signal is the first audio signal, and the next received audio signal is the second audio signal, Outputting a preceding first audio signal at the first transmission clock frequency, outputting a transmission clock having the first transmission clock frequency to the audio device while stopping output of the audio signal during a switching period, Another second audio signal that can be transmitted at the first transmission clock frequency in the signal received next from the broadcast is selected and controlled to output the audio signal at the first transmission clock frequency. ,
When the connected audio device is in the second mode, the received preceding audio signal is the first audio signal, and the next received audio signal is the second audio signal, The preceding first audio signal is output at the second transmission clock frequency, and the transmission clock having the second transmission clock frequency is output to the audio device while stopping the output of the audio signal during the switching period. A broadcast receiving apparatus that controls to output a second audio signal received by a second transmission clock frequency.   The broadcast receiving apparatus according to claim 1, wherein the first mode is a mode in which a transmission clock frequency of the output interface is available only at 48 kHz, and the second mode is a mode in which both 48 kHz and 96 kHz are available.   The broadcast receiving apparatus according to claim 1, further comprising a GUI (Graphical User Interface) processing unit for a user to select the first mode and the second mode.   When the control unit uses HDMI (High Definition Multimedia Interface) for connection with the audio device, EDID (Extended Display Identificaiton Data) or HDMI-CEC (High Definition Multimedia Interface-Consumer Electronics Control) specified by the HDMI is used. 2. The broadcast receiving apparatus according to claim 1, wherein it is automatically determined whether to adopt the first mode or the second mode based on the information of 1.   The broadcast according to claim 4, wherein the control unit adopts the second mode when it is detected from the HDMI EDID or HDMI-CEC information that the audio device can handle MPEG4-ALS. Receiver.   5. The control unit adopts the second mode when it is detected from the HDMI EDID or HDMI-CEC information that the audio device can handle MPEG4-AAC 22.2 ch. Broadcast receiver.   In addition to the first mode in which only the first transmission clock frequency can be used and the second mode in which the first and second transmission clock frequencies can be used, the control unit can add first, second, and When a third mode in which three transmission clock frequencies are available is provided, the relationship between the first mode and the second mode is defined as the relationship between the first mode and the third mode, and the second mode. The broadcast receiving apparatus according to claim 1, wherein the broadcast receiving apparatus is applied to a relationship between the mode and the third mode. A broadcast receiving method for receiving a broadcast in which a first audio signal and a second audio signal are selectively transmitted and outputting the received audio signal to an externally connected audio device,
There are a first transmission clock frequency and a second transmission clock frequency as transmission clock frequencies for audio signal transmission with the externally connected audio device, and the first audio signal has a first transmission clock frequency and a second transmission clock frequency. It is possible to transmit at both of the transmission clock frequencies, the second audio signal can be transmitted only at the second transmission clock frequency, and switching between the first audio signal and the second audio signal during broadcasting. If there is a notification of voice switching information in advance,
Classifying the audio device into a first mode corresponding only to the first transmission clock frequency and a second mode corresponding to both the first transmission clock frequency and the second transmission clock frequency; The transmission clock frequency is determined based on the voice switching information,
When the connected audio device is in the first mode, the preceding audio signal received from the audio switching information is the first audio signal and the next audio signal received is the second audio signal. If it is determined that the preceding first audio signal is output at the first transmission clock frequency, and the output of the audio signal is stopped during the switching period, the transmission clock of the first transmission clock frequency is output. To the audio device, select another second audio signal that can be transmitted at the first transmission clock frequency in the signal next received from the broadcast, and select another second audio signal according to the first transmission clock frequency. Control to output a voice signal,
When the connected audio device is in the second mode, the preceding audio signal received from the audio switching information is the first audio signal, and the next received audio signal is the second audio signal. If it is determined that the preceding first audio signal is output at the second transmission clock frequency, and the output of the audio signal is stopped during the switching period, the transmission clock of the second transmission clock frequency is output. Is output to the audio device, and the second audio signal to be received next is controlled to be output at the second transmission clock frequency.   9. The broadcast receiving method according to claim 8, wherein the first mode is a mode in which the transmission clock frequency of the output interface is available only at 48 kHz, and the second mode is a mode in which both 48 kHz and 96 kHz are available.   9. The broadcast receiving method according to claim 8, wherein the first mode and the second mode are selected by a user's designated operation input.   When using HDMI (High Definition Multimedia Interface) for connection with the audio device, from the information of EDID (Extended Display Identificaiton Data) or HDMI-CEC (High Definition Multimedia Interface-Consumer Electronics Control) specified by the HDMI, 9. The broadcast receiving method according to claim 8, wherein the first mode or the second mode is automatically judged and switched.   The broadcast receiving method according to claim 11, wherein the second mode is adopted when it is detected from the HDMI EDID or HDMI-CEC information that the audio device can handle MPEG4-ALS.   The broadcast receiving method according to claim 11, wherein the second mode is adopted when it is detected from the HDMI EDID or HDMI-CEC information that the audio device can handle MPEG4-AAC 22.2 ch.   In addition to a first mode in which only the first transmission clock frequency can be used, a second mode in which the first and second transmission clock frequencies can be used, first, second and third transmission clock frequencies And a third mode that can be used for the relationship between the first mode and the second mode, the relationship between the first mode and the third mode, the second mode and the third mode. 9. The broadcast receiving method according to claim 8, which is applied to the relationship with the mode.

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