JP2009192944A - Voice output device and voice output method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for reproducing two-channel voice which is down-mixed beforehand simultaneously with multi-channel voice. <P>SOLUTION: A voice output device includes: a separating section for separating a multi-channel compression data section and two-channel compression data section from a voice stream which is input from outside; a multi-channel decoder section for decoding the multi-channel compression data section and outputting it to a multi-channel terminal; and a two-channel decoder section for decoding the two-channel compression data section and outputting it to a two-channel dedicated terminal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an improvement in an audio output apparatus and an audio output method for outputting a compressed audio stream, and more particularly to a method for simultaneously outputting a plurality of sounds.

  As is well known, in recent years, an optical disk such as a DVD (digital versatile disk) has become widespread as a digital recording medium. At present, a high-definition next-generation DVD standard called HD (high definition) -DVD capable of higher density recording than DVD has been completed.

  By the way, in this type of next-generation optical disc, new formats such as DTS (digital theater system) -HD (high definition) and dolby true HD have been developed for audio recording. In this new format, the content creator can freely set the number of channels for audio playback.

  Heretofore, a multi-channel model such as an HD DVD player conventionally has a 2-channel dedicated terminal independently of the multi-channel terminal. Here, the output sound to the 2-channel dedicated terminal is generated by performing a downmix process from the sound output to the multi-channel terminal.

On the other hand, the next-generation audio codec that forms a new format has other characteristics than the lossless compression method. That is, 2-channel audio that has been downmixed in advance can be encoded in the form of coexistence with multichannel audio, and in this case, the downmix coefficient at the time of encoding does not exist in the stream. In addition, there is a feature that multi-channel audio can be decoded using an intermediate decoding result of 2-channel audio that has been downmixed in advance.

By the way, when such a stream is output to the 2-channel dedicated terminal by the conventional method, the following problems exist.
1. The premixed audio is different from the downmix audio output by the player (because the downmix coefficient during encoding is unknown)
2. Original lossless audio is output as lossy audio via downmix processing (quality degradation)
Of these, the technology for solving the problem that the downmix 2-channel audio intended by the content creator cannot be output is demanded particularly with respect to the problem 1 described above. This is because the downmix coefficient to 2ch used at the time of encoding by the content creator is unknown, and the player cannot perform the downmix process using an appropriate downmix coefficient.

On the other hand, in the audio signal processing apparatus described in Patent Document 1, when a multi-channel audio signal is input and a 2-channel digital signal is output, the input channel is automatically converted to a 2-channel digital audio signal. It is to switch. However, there is a problem that a technique for solving the above problem is not disclosed.
JP 2007-104159 A

  An object of the present invention is to provide a technique for reproducing two-channel audio that has been downmixed in advance, simultaneously with multi-channel audio.

  In order to solve the above-described problems, an audio output device of the present invention includes a separation unit that separates a multi-channel compressed data unit and a 2-channel compressed data unit from an externally input audio stream, and decodes the multi-channel compressed data unit. And a multi-channel decoder for outputting to a multi-channel terminal, and a 2-channel decoder for decoding the 2-channel compressed data portion and outputting to a dedicated 2-channel terminal.

  According to the present invention, it is possible to obtain a technology for reproducing two-channel audio that has been premixed in advance simultaneously with multi-channel audio.

  Embodiments of the present invention will be described below.

Embodiment 1 according to the present invention will be described with reference to FIGS.
First, a multi-channel model of an HD DVD player usually has a 2-channel audio output terminal independently of a multi-channel audio output terminal. When decoding multi-channel audio, the 2-channel audio output terminal outputs audio obtained by down-mixing the multi-channel audio.

  On the other hand, next-generation audio compression methods (such as TrueHD and DTS-HD) are capable of lossless compression, multi-channel audio in one compressed audio stream, and down-loaded when content providers pre-encode. A mechanism is provided so that mixed two-channel audio can exist independently. At this time, the information of the downmix coefficient used at the time of encoding is not recorded in the compressed audio stream.

  In the player having such a conventional configuration, when the compressed audio stream is reproduced, the multi-channel audio is first decoded, and the decoded multi-channel audio is subjected to a downmix process, whereby the 2-channel audio is converted. Try to generate. The audio output from the 2-channel audio output terminal cannot be downmixed using the optimal downmix coefficient because the downmix coefficient is unknown. There is a problem that it is different from voice. Further, the downmix processing on the player side impairs the advantage of lossless compression of the next generation audio compression method. The present embodiment aims to solve this problem.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an outline of a disk reproducing apparatus 11 described in this embodiment. The disc playback apparatus 11 includes a disc drive unit 13 that is loaded with an optical disc 12 such as an HD-DVD and reads the recorded data.

  The data read from the optical disk 12 by the disk drive unit 13 is temporarily stored in the track buffer 14 and then supplied to the demultiplexer unit 15. The demultiplexer unit 15 separates the input data into a compressed video stream and two compressed audio streams as main audio and sub audio.

  Among these, the compressed video stream is composed of a plurality of video packs (V_PCK). This compressed video stream is stored in the video input buffer 16 and then supplied to the video decoder 17 for decoding. Then, the decoded video data is supplied to a D / A (digital / analog) converter 18 and converted into analog video data, and then taken out to the outside via a video output terminal 19. It is used for video display on a monitor.

  The first compressed audio stream that is the main audio separated by the demultiplexer unit 15 is composed of a plurality of main audio packs (MA_PCK). The compressed audio stream is stored in the main audio input buffer 20 and then supplied to the main audio decoder 21 to decode the main audio. The main audio output from the main audio decoder 21 is stored in the main audio buffer 22 and then supplied to the mixing processing unit 23.

  Furthermore, the second compressed audio stream that is sub-audio separated by the demultiplexer unit 15 is composed of a plurality of sub-audio packs (SA_PCK). The compressed audio stream is stored in the sub audio input buffer 24 and then supplied to the Sub Audio decoder 25 to decode the sub audio. The sub audio output from the Sub Audio decoder 25 is stored in the sub audio buffer 26 and then supplied to the mixing processing unit 23.

  The disc playback apparatus 11 also includes an audio input unit 27. The audio input unit 27 acquires uncompressed (PCM: pulse code modulation) audio data (EF_PCM) as effect audio from, for example, a removable information recording medium or a network server. The uncompressed audio data (EF_PCM) acquired by the audio input unit 27 is stored in the effect buffer 28 and then supplied to the mixing processing unit 23.

  Further, the mixing coefficient set in the coefficient setting unit 29 is supplied to the mixing processing unit 23. This mixing coefficient is acquired from the optical disc 11 at the time of reproduction, for example, and is used when the main audio, the sub audio, and the effect audio are mixed in the mixing processing unit.

  The audio mixed by the mixing processing unit is converted into a transmission form compliant with, for example, the HDMI (high definition multimedia interface) standard by the interface unit 30 and then extracted to the outside through the digital audio output terminal 31. For example, an AV amplifier having a function of decoding a compressed audio stream is connected to the digital audio output terminal 31 so that high-quality audio reproduction with multiple channels can be performed.

  The video decoder 17 and the mixing processing unit 23 are controlled by the synchronization control unit 32 in terms of video output timing and audio output timing. Thus, finally, the displayed video and the reproduced audio are controlled to be synchronized.

  Here, in the disk reproducing apparatus 11, all the operations including the above-described reproducing operation are comprehensively controlled by the control unit 33. The control unit 33 incorporates a CPU (central processing unit) and the like, receives operation information from the operation unit 34 or operation information sent from the remote controller 35 and received by the light receiving unit 36, and the operation content is Each part is controlled to be reflected.

  In this case, the control unit 33 uses the memory unit 37. The memory unit 37 mainly includes a ROM (read only memory) storing a control program to be executed by the CPU of the control unit 33, a RAM (random access memory) for providing a work area to the CPU, And a non-volatile memory for storing various setting information and control information.

  FIG. 2 shows a functional configuration of a main part of the present embodiment. In the present embodiment, when both the multi-channel compressed audio and the 2-channel compressed audio are present in the input compressed audio stream, the separation unit 1 separates the multi-channel compressed audio data and the 2-channel compressed audio data. Thereafter, the multi-channel compressed audio data is input to the multi-channel audio decoder 2 and output to the multi-channel audio decoding process and the multi-channel output terminal 4. On the other hand, the separated 2-channel compressed audio data is input to the 2-channel audio decoder 3, and is output to the 2-channel audio decoding process and the 2-channel audio output terminal 5. In this way, in the playback of a compressed audio stream in which audio that has been downmixed in advance at the time of encoding is present and the downmix coefficient is unknown, the downmix processing is omitted and the 2-channel compressed audio data is decoded and output. As a result, the 2-channel audio intended by the content provider can be output to the 2-channel audio output terminal 5.

FIG. 3 is a flowchart of processing in the disc playback apparatus 11.
First, stream analysis is performed (step S201). Next, it is determined whether or not 2ch audio exists in the stream (step S202).
If it is determined in step S202 that 2ch audio exists, the multi-channel compressed data and the 2ch compressed data are separated (step S203). Next, an audio decoding process is performed (step S204).

  If it is determined in step S202 that there is no 2ch audio, multi-channel audio decoding processing is performed (step S205). Next, a downmix process is performed (step S206).

  Regardless of whether or not 2ch audio exists in step S202, the decoded audio is output to each output terminal (step S207).

A second embodiment of the present invention will be described with reference to FIGS. 1 and 3 to 4. Description of the parts common to the first embodiment is omitted.
FIG. 4 shows a configuration for reproducing the compressed stream. The difference from FIG. 2 is that multi-channel audio is restored from the intermediate decoding result of 2-channel compressed data and the decoded result of multi-channel compressed data.

  As another feature of the next-generation compressed audio system, a mechanism for decoding multi-channel audio using an intermediate decoding result of 2-channel audio down-mixed in advance is also provided. That is, difference information for decoding multi-channel audio from 2-channel compressed audio data is recorded in the multi-channel compressed audio data. Based on this difference information, the reconstructor 6 restores multi-channel audio.

A third embodiment according to the present invention will be described with reference to FIGS. Description of parts common to the first and second embodiments is omitted.
In addition, the present invention can be applied not only to an HD DVD player but also to an AV amplifier. FIG. 5 shows a configuration when applied to an AV amplifier. A compressed audio stream is transferred to the AV amplifier via a digital interface such as HDMI. This is received by the HDMI receiving unit 56, and multi-channel audio and 2-channel audio are decoded, respectively, and the multi-channel audio is output to a speaker and the 2-channel audio is output to an external connection device such as a TV via the HDMI transmission unit 57.

  As described above, in this embodiment, as an outline, when both the multi-channel compressed audio and the 2-channel compressed audio are present in the input compressed audio stream), the multi-channel compressed data portion, the 2-channel compressed data portion, Are separately decoded and output to the multi-channel terminal and the 2-channel dedicated terminal.

In addition, this invention is not limited to the said embodiment, In the range which does not deviate from the summary, it can implement in various modifications.
Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements according to different embodiments may be appropriately combined.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating an outline of a disk reproducing device according to an embodiment of the present invention. The functional block diagram which shows the principal part of the embodiment. The flowchart used for the same embodiment. The functional block diagram which shows the principal part of other embodiment of this invention. The functional block diagram which shows the principal part of other embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Separator, 2 ... Multi-channel audio decoder, 3 ... 2-channel audio decoder, 4 ... Multi-channel output terminal, 5 ... 2-channel audio output terminal, 6 ... Reconstructor, 11 ... Disc playback device, 12 ... Optical disc, DESCRIPTION OF SYMBOLS 13 ... Disk drive part, 14 ... Track buffer, 15 ... Demultiplexer part, 16 ... Video input buffer, 17 ... Video decoder, 18 ... D / A conversion part, 19 ... Video output terminal, 20 ... Main audio | voice input buffer, 21 ... ES extractor 22... Main audio buffer 23. Multiplexer 24. Sub audio input buffer 25. ES extractor 26. Sub audio buffer 27. Audio input 28. Effect buffer 29. Coefficient setting unit, 30 ... interface unit, 31 ... digital audio output terminal, 32 ... synchronization control unit, 33 ... control unit, 34 ... Production unit 35 ... Remote controller 36 ... Light receiving unit 37 ... Memory unit 51 ... Separation unit 52 ... Multi-channel audio decoder 53 ... 2-channel audio decoder 54 ... Multi-channel output terminal 55 ... 2-channel audio output Terminal, 56... HDMI receiver, 57... HDMI transmitter.

Claims (4)

A separation unit that separates the multi-channel compressed data portion and the 2-channel compressed data portion from an audio stream input from the outside;
A multi-channel decoder unit for decoding the multi-channel compressed data unit and outputting it to a multi-channel terminal;
An audio output device comprising: a 2-channel decoder for decoding the 2-channel compressed data portion and outputting it to a 2-channel dedicated terminal. A separation unit that separates the multi-channel compressed data portion and the 2-channel compressed data portion from an audio stream input from the outside;
A 2-channel decoder for decoding the 2-channel compressed data portion and outputting it to a 2-channel dedicated terminal, and for generating decoded intermediate data;
An audio output device comprising: a multi-channel decoder unit that decodes the multi-channel compressed data unit and outputs multi-channel audio reconstructed using a part of the decoded intermediate data to a multi-channel terminal. A receiving unit that receives an audio stream signal received from outside and outputs audio stream data;
A separation unit that separates the multi-channel compressed data portion and the 2-channel compressed data portion from the audio stream data;
A multi-channel decoder unit for decoding the multi-channel compressed data unit and outputting it to a multi-channel terminal;
A 2-channel decoder for decoding the 2-channel compressed data portion and outputting it to the transmitter;
An audio output device comprising: a transmission unit that outputs a signal based on the decoding result to a 2-channel dedicated terminal. A separation step of separating the multi-channel compressed data portion and the 2-channel compressed data portion from the audio stream input from the outside;
A multi-channel decoding step for decoding the multi-channel compressed data portion and outputting it to a multi-channel terminal;
An audio output method comprising: a 2-channel decoding step of decoding the 2-channel compressed data part and outputting the decoded data to a 2-channel dedicated terminal.

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