JP6000156B2 - Digital audio broadcast receiver - Google Patents

Description

  The present invention provides a digital audio broadcast receiving device that, when reception failure occurs in a channel being received, seamlessly outputs audio to audio received on another channel that broadcasts the same content as the channel being received. It relates to the technology to switch to.

  In digital audio broadcast receivers, when reception failure occurs in a channel being received, the technology to seamlessly switch the output audio to the audio received on another channel that is broadcasting the same content as the channel being received By comparing the audio that was reproduced from the audio data received on the digital audio broadcast channel being received with the audio received on another analog audio broadcast channel that is broadcasting the same content as the channel being received Calculates the delay time of the audio received on the analog audio broadcast channel relative to the audio reproduced from the audio data received on the digital audio broadcast channel, and delays the audio received on the analog audio broadcast channel by the calculated delay time In addition, the output audio is analyzed from the audio reproduced from the audio data received on the digital audio broadcast channel. Technology to switch the voice received in the channel of audio broadcasts are known (e.g., Patent Document 1).

Japanese Patent Laid-Open No. 10-247855

  In the digital audio broadcast receiving apparatus, when a reception failure occurs in the channel A of the digital audio broadcast being received, the channel of the other digital audio broadcast that is broadcasting the same content as the channel A being received is outputted. When seamlessly switching to the audio received at B, the above technique is applied, and the delay time is calculated by comparing audio reproduced from audio data received at two channels A and B of digital audio broadcasting, and calculating The sound received on channel B is delayed by the amount of the delay time, and the output sound is switched from the sound obtained by reproducing the audio data received on channel A to the sound obtained by reproducing the audio data received on channel B. As a result, an audio decoder for reproducing the audio data into audio and a buffer associated with the audio decoder are required for two channels. It increases the size of the audio broadcast receiving apparatus, and thus lead to and rising costs.

  Accordingly, an object of the present invention is to provide a digital audio broadcast receiving apparatus having a small configuration that can seamlessly switch output audio between digital audio broadcast channels.

  In order to achieve the above object, the present invention provides a digital audio broadcast receiving apparatus that receives a digital audio broadcast that broadcasts a sequence of encoded audio data that is compression-encoded audio data, a first receiving unit, An audio decoder that receives the transferred encoded audio data and decodes the transferred encoded audio data into audio data; audio output means that outputs audio represented by the audio data decoded by the audio decoder; And a control means. Here, each of the first receiving unit and the second receiving unit includes a digital tuner and an input buffer in which encoded audio data received by the digital tuner is stored. Further, the control means uses one of the first receiving unit and the second receiving unit as an active receiving unit and the other as a standby receiving unit, and While allowing the digital tuner to receive the broadcast channel, the encoded audio data stored in the input buffer of the active receiver is sent to the audio decoder during a period when the reception status of the digital tuner of the active receiver is good. And the broadcast channel received by the digital tuner of the active receiving unit when the reception state of the digital tuner of the active receiving unit deteriorates, and the digital tuner of the active receiving unit Reception of another broadcast channel that broadcasts the same content is started, and thereafter, the encoded audio data stored in the input buffer of the active receiving unit and The correspondence between the encoded speech data and the encoded speech data stored in the same input buffer of the reception unit of the standby system is calculated based on the coincidence of the data patterns of the encoded speech data, and the calculated correspondence Based on the stop of the transfer of the encoded audio data stored in the input buffer of the active receiving unit to the audio decoder and the encoded audio data stored in the input buffer of the standby receiving unit. Next to the start of transfer to the audio decoder, following the encoded audio data last transferred from the input buffer of the active receiving unit to the audio decoder before stopping the transfer, The encoded audio data subsequent to the same encoded audio data as the last transferred encoded audio data stored in the input buffer is the audio data. Performed to be transferred to Odekoda.

  Here, in such a digital audio broadcast receiving apparatus, the control means stops the transfer of the encoded audio data stored in the input buffer of the active receiving unit to the audio decoder and the standby system. When the encoded audio data stored in the input buffer of the receiving unit is started to be transferred to the audio decoder, the working system is subsequently selected from the first receiving unit and the second receiving unit. The receiving unit used as the standby unit and the receiving unit used as the standby system may be alternated.

  In the digital audio broadcast receiving apparatus described above, when the encoded audio data is an audio frame obtained by framing audio data that has been compression-encoded, the control means includes a digital tuner of the active receiving unit. When the reception state of the receiver deteriorates, the reception of the other broadcast channel broadcasting the same content as the broadcast channel received by the digital tuner of the active reception unit is received by the digital tuner of the standby reception unit After that, the audio frame stored in the input buffer of the active reception unit and the audio frame stored in the input buffer of the standby reception unit that is the same as the audio frame Correspondence is calculated based on the coincidence of the data pattern of the entire voice frame or a part thereof, and based on the calculated correspondence, reception of the active system The transfer of the audio frame stored in the input buffer to the audio decoder and the transfer of the audio frame stored in the input buffer of the standby receiving unit to the audio decoder are transferred. The last transferred audio frame stored in the input buffer of the standby receiving unit following the last transferred audio frame from the input buffer of the active receiving unit to the audio decoder before stopping The audio frame following the same audio frame may be transferred to the audio decoder.

  According to the digital audio broadcast receiving apparatus as described above, seamless audio switching between delayed broadcast channels can be realized by providing two systems of digital tuners and input buffers without providing two systems such as an audio decoder. can do.

  As described above, according to the present invention, it is possible to provide a digital audio broadcast receiving apparatus having a small configuration that seamlessly switches output audio between digital audio broadcast channels.

It is a block diagram which shows the structure of the digital audio broadcasting receiver which concerns on embodiment of this invention. It is a flowchart which shows the seamless audio | voice switching process which concerns on embodiment of this invention. It is a flowchart which shows the input buffer switching process which concerns on embodiment of this invention. It is a figure which shows the process example of the input buffer switching process which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 shows the configuration of a digital audio broadcast receiving apparatus according to this embodiment.
As shown in the figure, the digital audio broadcast receiving apparatus includes two systems, a digital tuner 101 that receives digital audio broadcast, a demultiplexing unit 102, an audio frame restoration unit 103, and an input buffer 104, one of which is It is used as an active system, and the other system is used as a standby system.

The digital broadcast receiving apparatus also includes a display unit 105, an operation unit 106, a control unit 107, a buffer control unit 108, an audio decoder 109, an output buffer 110, a DA converter 111 (DAC 111), an amplifier 112, and a speaker 113.
Here, the control unit 107 receives the setting of the channel of the digital audio broadcast received from the user via the operation unit 106, and sets the channel for which the setting has been received as a reception channel in the active digital tuner 101.
On the other hand, the active digital tuner 101 receives broadcast data of a digital audio broadcast channel set as a reception channel, and outputs it to the demultiplexing unit 102 of the same system. Here, the broadcast data of the digital audio broadcast includes control information indicating the identification of other digital audio broadcast channels that are broadcasting the same program (contents) as the broadcast data, and time-interleaved audio. Stream data. The audio stream data includes audio frames obtained by compressing and encoding audio data representing audio in the order of the audio data playback time.

Here, each digital tuner 101 also performs a process of detecting the good / bad level of the reception state of the digital audio broadcast channel set as the reception channel and notifying the control unit 107 of it.
Next, the demultiplexing unit 102 separates control information from the broadcast data output from the digital tuner 101 of the same system, outputs the control information to the control unit 107, and is time-interleaved from the broadcast data output from the digital tuner 101. The audio stream data is separated and output to the audio frame restoration unit 103 of the same system.

  The audio frame restoration unit 103 performs processing such as time deinterleaving on the time-interleaved audio stream data output from the demultiplexing unit digital tuner of the same system and restores the audio frame. The compressed and encoded audio data included in the audio frame is stored in the input buffer 104 of the same system in the order of reproduction time.

  The buffer control unit 108 controls sequential transfer of audio frames stored in the active input buffer 104 to the audio decoder 109, and the audio decoder 109 performs compression encoding stored in the transferred audio frames. The audio data is decoded, and the decoded audio data is stored in the output buffer 110.

The audio data stored in the output buffer 110 is sequentially transferred to the DAC 111, converted into an analog audio signal, amplified by the amplifier 112, output to the speaker 113, and the audio represented by the analog audio signal is output from the speaker 113 to the user. Is output for.
Hereinafter, in such a digital audio broadcast receiving apparatus, when reception failure occurs in the channel being received, the audio output is received by another channel that broadcasts the same content as the channel being received The seamless voice switching operation for seamless switching to will be described.

FIG. 2 shows a procedure of seamless voice switching processing performed by the control unit 107 for the seamless voice switching operation.
As shown in the figure, in this processing, the deterioration of the reception state of the active digital tuner 101 from a predetermined reference is monitored based on the good / bad level of the reception state output from the active digital tuner 101. (Step 202).
If the reception state of the active digital tuner 101 is deteriorated from a predetermined reference, the channel received by the active digital tuner 101 from the control information output from the active demultiplexing unit 102, and The other digital audio broadcasting channels broadcasting the broadcast data of the same program (contents) are calculated as alternative channels (step 204).

Next, an alternative channel is set as a reception channel in the standby digital tuner 101, and the reception status of the alternative channel of the standby digital tuner 101 is checked (step 206).
If the reception status of the alternative channel is not good (step 208), the processing returns to step 202.
On the other hand, if the reception status of the alternative channel is good, processing of the broadcast data of the alternative channel is started in the standby system (step 210). That is, the standby demultiplexing unit 102 and the audio frame restoration unit 103 sequentially store the audio frames included in the alternative channel broadcast data received by the standby digital tuner 101 in the standby input buffer 104.

Then, the buffer control unit 108 is instructed to execute the input buffer switching process (step 212). Here, the input buffer switching process performed by the buffer control unit 108 will be described later.
If a notification of the completion of execution of the input buffer switching process is received from the buffer control unit 108 (step 214), the current standby system is switched to the active system by replacing the active system with the standby system. Is set as a standby system (step 216), and the process returns to step 202.

The seamless voice switching process performed by the control unit 107 has been described above.
Next, an input buffer switching process that is started by the buffer control unit 108 in accordance with the instruction to execute the step 212 of the seamless voice switching process of the control unit 107 will be described.
FIG. 3 shows a procedure of input buffer switching processing performed by the buffer control unit 108.
As shown in this figure, in this process, the audio frame stored in the active input buffer 104 before the start of the input buffer switching process, that is, before the start of storing the audio channel of the alternative channel in the standby input buffer 104. Waits for completion of transfer to the audio decoder 109 (step 302).

  Next, each audio frame that has not been transferred to the audio decoder 109 stored in the active input buffer 104 is given an order in the reproduction time order of the compressed and encoded audio data included in the audio frame, and the standby is performed. In order to give each audio frame not transferred to the audio decoder 109 stored in the system input buffer 104 in order of the reproduction time of the compressed and encoded audio data included in the audio frame, The audio frame stored in the input buffer 104 is searched for an audio frame that matches the mth audio frame of the active input buffer 104 (step 304). Here, m is the number of audio frames transferred by digital audio broadcasting during time Tmax, where Tmax is the maximum delay time between different channels broadcasting the same program.

  Also, the match between voice frames may be determined by matching the data pattern of the entire voice frame, or may be determined by matching the data pattern of a part of the voice frame. Also, in the case where a match between audio frames is determined from a match in a part of the data pattern of the audio frame, as an example of the audio frame that determines the match, for example, when the audio frame is in mp2 format For example, the scale factor (volume for each frequency band) included in the audio frame, the CRC in the case where the audio frame includes CRC, and the like can be used. In addition to the match between the sound frames, the match between the sound frames may be determined by matching the sound frames before and after. That is, the m−1th, mth, and m + 1th audio frames of the active input buffer 104, and the w−1th, wth, and w + 1th audio frames of the standby input buffer 104 When they match each other, it may be determined that the mth audio frame of the active input buffer 104 matches the wth audio frame of the standby input buffer 104.

Then, p = km is calculated, where k is the order of the searched audio frames in the standby input buffer 104 (step 306).
Then, the process waits for completion of transfer of the audio frame that is the nth audio frame at the time of execution of steps 304 to 306 stored in the active input buffer 104 to the audio decoder 109 (step 308). Here, n is a positive integer greater than or equal to −p. For example, n is the smallest number among positive integers greater than or equal to −p.
When the transfer of the nth audio frame stored in the active input buffer 104 to the audio decoder 109 is completed (step 308), the audio of the audio frame stored in the active input buffer 104 is completed. The transfer to the decoder 109 is ended (step 310), and the standby system is processed for the audio frames in the order after the n + p + 1th audio frame at the time of execution of steps 304-306 stored in the standby system input buffer 104. The audio frames stored in the input buffer 104 are sequentially transferred to the audio decoder 109 (step 312).

Then, the end of execution of the input buffer switching process is notified to the control unit 107 (step 314), and the input buffer switching process is terminated.
Hereinafter, an operation example of such an input buffer switching process is shown in FIG.
Now, it is assumed that the broadcast data of the alternative channel is delayed by an amount equivalent to two audio frames from the broadcast data of the channel received by the active digital tuner 101.
Further, after the storage of the substitute channel audio frame in the standby input buffer 104 is started, the audio frame first received by the active digital tuner 101 is the audio frame F (t = n-4), Assume that the audio frame first received by the standby digital tuner 101 is an audio frame F (t = n−6).

  Then, in this case, when the transfer of the voice frame stored in the active input buffer 104 to the audio decoder 109 is completed before the start of storing the voice frame of the alternative channel in the standby input buffer 104, FIG. As shown in FIG. 3, the active input buffer 104 stores audio frames after F (t = n-4), and the standby input buffer 104 stores audio frames after F (t = n-6). Stored state.

  At this point, when the input buffer switching process is described as m = 5, an audio frame that matches the fifth (N0.5) audio frame F (t = n) of the active input buffer 104 is set as a standby system. Search from the input buffer 104. In this case, the seventh (N0.7) speech frame F (t = n) in the standby input buffer 104 is searched.

Also, since the searched audio frame is the seventh audio frame, k = 7 and p = km = 2.
Next, assuming that n is the minimum number of positive integers greater than or equal to −p, since n = 1, the first audio frame F (t = n−4) of the active input buffer 104 is obtained. ) Transfer to the audio decoder 109 is completed, the input buffer switching processing ends the transfer of the audio frame from the active input buffer 104 to the audio decoder 109, and the audio frame of the standby input buffer 104 is transferred. The transfer to the audio decoder 109 is started from the (n + p + 1) th fourth audio frame F (t = n−3) in the standby input buffer 104.

  As a result, audio frames F (t = n-4), F (t = n-3), F (t = n-2), and audio frames are transmitted to audio decoder 109 in order of playback time without interruption. As a result, seamless voice switching from the voice of the channel received by the active digital tuner 101 to the voice of the alternative channel is realized.

Next, contrary to the case shown in FIG. 4a, the broadcast data of the channel received by the active digital tuner 101 is delayed by an amount corresponding to two audio frames, rather than the broadcast data of the alternative channel. Shall.
Further, after the storage of the substitute channel audio frame in the standby input buffer 104 is started, the audio frame first received by the active digital tuner 101 is the audio frame F (t = n-4), Assume that the audio frame first received by the standby digital tuner 101 is an audio frame F (t = n−2).

  Then, in this case, when the transfer of the audio frame stored in the active input buffer 104 to the audio decoder 109 is completed before the storage of the alternative channel audio frame in the standby input buffer 104 is started, FIG. As shown in FIG. 4, the active input buffer 104 stores audio frames after F (t = n-4), and the standby input buffer 104 stores audio frames after F (t = n-2). Stored state.

  At this point, when the input buffer switching process is described as m = 5, an audio frame that matches the fifth (N0.5) audio frame F (t = n) of the active input buffer 104 is set as a standby system. Search from the input buffer 104. In this case, the third (N0.3) speech frame F (t = n) in the standby input buffer 104 is searched.

Further, since the searched voice frame is the third voice frame, k = 3 and p = km = −2.
Next, if n is the minimum number of positive integers greater than or equal to −p, then n = 2.
When the transfer of the second audio frame F (t = n−3) of the active input buffer 104 to the audio decoder 109 is completed, the input buffer switching processing is performed for the audio frame from the active input buffer 104. The transfer of the audio decoder 109 is terminated, and the transfer of the audio frame of the standby input buffer 104 to the audio decoder 109 is changed to n + p + 1 = 1th audio frame F (t = n of the standby input buffer 104. Start from -2).

  As a result, the audio decoder 109 receives audio frames F (t = n-4), F (t = n-3), F (t = n-2), F (t = n-1), in the order of playback time. The audio frames are transmitted without interruption. As a result, seamless audio switching from the audio of the channel received by the active digital tuner 101 to the audio of the alternative channel is realized.

The embodiment of the present invention has been described above.
As described above, according to the present embodiment, if two systems of the digital tuner 101, the demultiplexing unit 102, the audio frame restoration unit 103, and the input buffer 104 are provided without providing two systems such as the audio decoder 109, the delay of Seamless audio switching between broadcast channels can be realized.

  DESCRIPTION OF SYMBOLS 101 ... Digital tuner, 102 ... Demultiplexing part, 103 ... Audio | voice frame decompression | restoration part, 104 ... Input buffer, 105 ... Display part, 106 ... Operation part, 107 ... Control part, 108 ... Buffer control part, 109 ... Audio decoder, 110 ... Output buffer, 111 ... DAC, 112 ... Amplifier, 113 ... Speaker.

Claims (3)

A digital audio broadcast receiver that receives a digital audio broadcast that broadcasts a sequence of encoded audio data that is compression-encoded audio data,
A first receiver;
A second receiving unit;
An audio decoder that receives the transferred encoded audio data and decodes the transferred encoded audio data into audio data;
Audio output means for outputting audio represented by the audio data decoded by the audio decoder;
Control means,
Each of the first receiving unit and the second receiving unit includes a digital tuner and an input buffer in which encoded audio data received by the digital tuner is stored. The control unit includes the first receiving unit. One of the receiver and the second receiver is used as the active receiver and the other is used as the standby receiver, so that the digital tuner of the active receiver receives the broadcast channel and the active receiver While the reception state of the digital tuner of the system receiving unit is good, the encoded audio data stored in the input buffer of the working system receiving unit is transferred to the audio decoder, and
When the reception status of the digital tuner of the active receiving unit deteriorates, the same contents as the broadcast channel received by the digital tuner of the active receiving unit are broadcast to the digital tuner of the standby receiving unit. Reception of the other broadcast channel is started, and thereafter, the encoded audio data stored in the input buffer of the active reception unit and reception of the standby system that is the same as the encoded audio data The correspondence with the encoded audio data stored in the input buffer of the unit is calculated based on the coincidence of the data pattern of the encoded audio data, and based on the calculated correspondence, the input buffer of the receiving unit of the active system Stop the transfer of the encoded audio data stored in the audio decoder to the audio decoder and the encoded audio data stored in the input buffer of the reception unit of the standby system The start of the transfer to the audio decoder is followed by the input buffer of the standby receiving unit following the encoded audio data last transferred from the input buffer of the active receiving unit to the audio decoder before the transfer is stopped. The digital audio broadcast receiving apparatus is characterized in that the encoded audio data that follows the encoded audio data that is the same as the last transferred encoded audio data that is stored in is transmitted to the audio decoder. . The digital audio broadcast receiving apparatus according to claim 1,
The control means stops the transfer of the encoded audio data stored in the input buffer of the active receiving unit to the audio decoder and the encoded audio stored in the input buffer of the standby receiving unit. When the transfer of data to the audio decoder is started, a receiving unit used as an active system and a receiving unit used as a standby system among the first receiving unit and the second receiving unit are subsequently used. A digital audio broadcasting receiver characterized in that it is replaced. The digital audio broadcast receiving apparatus according to claim 1 or 2,
The encoded audio data is an audio frame obtained by framing compression-encoded audio data,
The control means includes a broadcast channel that is received by the digital tuner of the active receiving unit to the digital tuner of the standby receiving unit when the reception state of the digital tuner of the active receiving unit is deteriorated. And start reception of another broadcast channel that broadcasts the same content, and then, the audio frame stored in the input buffer of the active reception unit and the standby system that is the same as the audio frame The correspondence with the audio frame stored in the input buffer of the receiving unit is calculated based on the match of the data pattern of the entire audio frame or a part of the audio frame, and based on the calculated correspondence, the receiving unit of the active system Stopping transfer of audio frames stored in the input buffer to the audio decoder and the audio frames stored in the input buffer of the reception unit of the standby system The start of the transfer to the audio decoder, following the voice frame last transferred from the input buffer of the active receiver to the audio decoder before the transfer is stopped, A digital audio broadcast receiving apparatus, wherein an audio frame subsequent to the same audio frame as the last transferred audio frame stored in the input buffer is transferred to the audio decoder.