JP2001100792A - Encoding method, encoding device and communication system provided with the device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoding device which executes encoding which can constitute a decoding device corresponding to an apparatus exclusively used for two-channel reproducing at a low cost. SOLUTION: This encoding device 110 receives a multi-channel sound signal and outputs encoded transmission data. The encoding device 100 includes a down mix circuit 120, which receives a multi-channel sound signal of 5 channels to output a two-channel reproduced signal, and an encoding processing circuit 130 which encodes a part of the multi-channel sound signal and the two-channel reproduced signal and outputs transmission data Yadd.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoding method and an encoding device, and more particularly, to an encoding method for compressing and encoding a multi-channel signal, an encoding device, and a communication system including the same.

[0002]

2. Description of the Related Art Torby digital system and MPGE-AA
A compression encoding system capable of multi-channel reproduction such as the C system is used.

[0005] FIG. 5 is a block diagram showing a structure adopted in MPEG-ACC.
It is a conceptual diagram which shows the speaker arrangement | positioning of a channel system.

Referring to FIG. 5, in the MPEG-ACC system, a multi-channel audio signal corresponding to five speakers is encoded. In the five-channel system, Lch. (Left channel) and Rch. (Right channel) plus Cc
h. (Center channel), LSch. (Left surround channel) and LSch. (Right surround channel), and especially, the addition of the center channel speaker greatly improves the sound image localization and sound quality, which are important for dialogue in movies and solo musical instruments. Have. By adopting such a multi-channel system, it is possible to obtain a high-quality reproduced sound full of a sense of reality.

FIG. 6 is a conceptual diagram for describing a recording format of audio code data according to the MPEG-ACC system.

Referring to FIG. 6, an audio decoding unit of audio code data according to the MPEG-ACC system includes header information and multi-channel audio data. The multi-channel audio data includes center channel, left channel, right channel, left surround channel, and right surround channel data. As described above, the compression encoding of the multi-channel signal is executed by encoding and recording the audio signal corresponding to each speaker constituting the multi-channel for each audio decoding unit. By decoding the encoded data corresponding to each channel for each audio decoding unit using the decoding device, it is possible to reproduce a multi-channel audio signal.

[0007]

As described above, a reproduced signal corresponding to a multi-channel can be obtained by receiving and decoding, for example, audio code data according to the MPEG-AAC system.

[0008] However, in the market, audio devices that output reproduced sounds through two speakers are dominant in relation to housing conditions. Many devices, such as DVDs and TVs, have only two output terminals from the beginning. Therefore, in order to reproduce a multi-channel signal corresponding to these two-channel reproduction-dedicated devices, the signals of all the recorded channels are decoded, and the signals obtained by decoding are combined to form a new two-channel signal. It was necessary to obtain a reproduced signal of

FIG. 7 is a block diagram showing a configuration of a conventional multi-channel communication system 500 capable of supporting two-channel reproduction.

Referring to FIG. 7, a communication system 500 includes:
Encoding device 51 for compression-encoding a multi-channel signal
0 and the transmission data Ya output from the encoding device 510
and a decoding device 550 for decoding d and outputting a two-channel reproduction signal.

The encoding device 510 receives the audio signals X (C), X (L), X (R), X (SL) and X (SR) of each channel and has the recording format described with reference to FIG. The transmission data Yad is output. Decoding device 550
Receives a transmission data Yad, decodes it, and outputs an audio signal of each channel.
And a downmix signal generation circuit 570 that outputs two-channel reproduced signals X (Lo) and X (Ro) based on the five-channel audio signals decoded by the decoding processing circuit.

Thus, in the decoding device 550,
The audio signals of all channels are decoded by the decode processing circuit 560, and these signals are further downmixed to obtain two-channel reproduced signals X (Lo) and X (Ro). For this reason, the decoding LSI used in the decoding device 550 is required to have high-speed and large-capacity arithmetic processing capability, and it has been extremely difficult to reduce the cost of the decoding device.

The present invention has been made to solve such a problem, and an object of the present invention is to make it possible to configure a decoding device corresponding to a two-channel reproduction-only device at low cost. An object of the present invention is to provide an encoding device that performs encoding and a communication system including the encoding device.

[0014]

According to a first aspect of the present invention, there is provided an encoding method for encoding a multi-channel signal composed of N channel signals (N: a natural number of 3 or more). Downmix the channel signal
Generating a two-channel playback-only signal corresponding to the channel playback device, independently encoding the two-channel playback-only signal and another channel signal,
Recording the encoded data for each decoding unit according to a predetermined format. The recording step independently records encoded data respectively corresponding to the two-channel reproduction-only signal and the other channel signals.

According to a second aspect of the present invention, there is provided the encoding method according to the first aspect, wherein the recording step is a step of converting the encoded data corresponding to the two-channel reproduction-only signal into another channel signal. It is recorded before the encoded data.

According to a third aspect of the present invention, in the encoding method of the first aspect, the N channel signals are (N-2) other channel signals to be compression-encoded. And the other two channel signals, and the other channel signals are selected such that the other two channel signals can be reproduced by synthesizing the other channel signals and the two-channel reproduction dedicated signal. Is done.

According to a fourth aspect of the present invention, there is provided an encoding apparatus for encoding a multi-channel signal composed of N channel signals (N: a natural number of 3 or more), wherein the N channel signals are downmixed. And a downmix circuit for generating a two-channel playback dedicated signal corresponding to the two-channel playback device, and encoding the two-channel playback dedicated signal and another channel signal to generate a two-channel playback dedicated signal and another channel signal. And an encoding processing circuit for outputting a transmission data signal in which encoded data corresponding to each of them is recorded independently.

According to a fifth aspect of the present invention, there is provided the encoding apparatus according to the fourth aspect, wherein the encoding processing circuit records the encoded data for each decoding unit according to a predetermined recording format. Is generated, and in the recording format, the encoded data corresponding to the two-channel reproduction-only signal is recorded earlier than the encoded data corresponding to the other channel signals.

The encoding device according to claim 6 is the encoding device according to claim 4, wherein the encoding processing circuit removes two channel signals from the multi-channel signal (N-2). The two channel signals can be reproduced by encoding the other channel signals and the two-channel reproduction-only signal, and combining the other channel signals with the two-channel reproduction-only signal. Selected as is.

A communication system according to a seventh aspect is a communication system for transmitting and receiving a multi-channel signal composed of N channel signals (N: a natural number of 3 or more), wherein an encoding device for encoding the multi-channel signal is provided. The encoding apparatus includes: a downmix circuit that downmixes N channel signals to generate a two-channel playback dedicated signal corresponding to a two-channel playback device; and a two-channel playback dedicated signal and another channel signal. Encoding
And an encoding processing circuit for outputting a transmission data signal in which encoded data corresponding to each of the two-channel reproduction-only signal and the other channel signals is recorded independently, and decodes the transmission data signal to output a reproduced audio signal. The decoding device further includes a decoding device, and the decoding device includes a first decoding processing circuit that decodes encoded data corresponding to the two-channel reproduction-only signal.

The communication system according to claim 8 is the communication system according to claim 7.
The communication system according to claim 1, wherein the encoding processing circuit records the encoded data for each decoding unit according to a predetermined recording format to generate a transmission data signal, and the recording format corresponds to a two-channel reproduction-only signal. The encoded data is recorded before the encoded data corresponding to the other channel signals.

The communication system according to the ninth aspect is the communication system according to the seventh aspect.
The communication system according to claim 1, wherein the encoding processing circuit encodes (N-2) other channel signals obtained by removing two channel signals from the multi-channel signal, and a two-channel reproduction-only signal. , Other channel signals
By combining the other channel signal and the two-channel reproduction-only signal, two channel signals that are not to be encoded are selected so as to be reproducible, and the decoding device receives the transmission data signal, A second decoding device for decoding the encoded data corresponding to the other channel signals, and two channel signals which are not to be encoded by receiving decoding outputs of the first and second decoding devices. And a signal processing circuit that outputs

A communication system according to a tenth aspect is the communication system according to the ninth aspect, wherein the multi-channel signal is a signal according to the MPEG-AAC method, and the two channel signals that are not to be encoded are: , Corresponding to surround speaker audio signals.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings. The same reference numerals in the drawings indicate the same or corresponding parts.

[First Embodiment] FIG. 1 is a block diagram illustrating a configuration of a multi-channel communication system 100 capable of supporting two-channel reproduction according to a first embodiment.

Referring to FIG. 1, communication system 100 includes:
Multi-channel audio signals X (C), X (L), X
(R), encoding apparatus 110 that receives X (SL) and X (SR) to output transmission data Yadd, and receives transmission data Yadd and outputs 2-channel reproduced signals X (Lo) and X (Ro) And a decoding device 150 that performs the decoding.

The first embodiment is characterized in that signals necessary for two-channel reproduction are down-mixed in advance at the time of encoding, and the obtained two-channel reproduced signals are directly encoded.

Encoding device 110 receives 5-channel audio signals X (C), X (L), X (R), X (SL) and X (SR), and reproduces 2-channel reproduced signals X (Lo) and X (Lo). Downmix circuit 120 for outputting X (Ro)
And audio signals X (C), X (L) and X (R) and X (Lo) and X which are outputs of a downmix circuit signal.
(Ro), and compression-encodes the transmission data Y
and an encoding processing circuit 130 for outputting the add.

The downmix circuit 120 receives the five-channel audio signal forming the multi-channel signal, performs downmixing in accordance with the following equations (1) and (2), and performs the two-channel reproduction dedicated signal X (Lo) and X (Ro) is output.

X (Lo) = X (L) + α · X (C) + β · X (SL) (1) X (Ro) = X (R) + α · X (C) + β · X (SR) (2) Note that α and β in the expressions (1) and (2) are constants.

An encoding processing circuit 130 receives X (C), X (L) and X (R), which are parts of the multi-channel signal, and the downmix signals X (Lo) and X (Ro) and compresses them. And outputs a transmission signal Yadd.

FIG. 2 is a conceptual diagram illustrating a recording format of a transmission signal Yadd output from the encoding apparatus according to the first embodiment for each audio decoding unit.

Referring to FIG. 2, an audio decoding unit of transmission signal Yadd includes header information and multi-channel audio data. Multi-channel audio data is obtained from Loch. And Roch. , And Cch. Which is a part of the multi-channel signal. , Lch. And Rch. And audio data corresponding to. These audio data are recorded independently.

[0034] Also, the SLch. And SRch. Is replaced with the data of Loch. And Roch. Since audio data corresponding to the audio data is included, the recording capacity of each audio decoding unit is not different from that of the related art. Further, the recording format of the multi-channel audio data portion is such that the down-mix signal necessary for exclusive use for 2-channel reproduction is recorded first, and then the multi-channel signal is recorded. In this case, the decoding processing capability of the decoding device can be efficiently used.

The decoding device 150 receives the transmission signal Yadd and executes a decoding process. 2 is included in the transmission signal Yadd.
Since the downmixed signal dedicated to channel reproduction is directly recorded, the decoding processing circuit 160 included in the decoding device 150 only decodes the signal for two channels and outputs the downmix signal required for two-channel reproduction. It is possible to get. When the purpose is to reproduce only two channels, the header information and the Loch. And Roch. By decoding up to the signal of the remaining channels and skipping the information of the remaining channels without processing, an audio signal required for 2-channel reproduction can be obtained. In this case, the signal processing capacity required for the decoding processing circuit may be about 2/5 of the conventional ability to decode all five channels, and an inexpensive LSI can be used. Can be reduced in cost. Further, since decoding is not performed on signals of useless channels, it is possible to reduce the power consumption of a decoding device dedicated to 2-channel reproduction.

Further, as described with reference to FIG. 2, the recording capacity for each audio decoding unit is not different from that of the conventional one, so that it is not necessary to improve the performance of the decoding processing circuit in response to the change of the recording format.

[Modification of First Embodiment] In a modification of the first embodiment, the original multi-channel recording format corresponding to the transmission data recording format which can easily cope with the two-channel reproduction described with reference to FIG. Provided is a configuration of a decoding device that can decode all channel signals.

FIG. 3 is a block diagram illustrating a configuration of a communication system 200 according to a modification of the first embodiment of the present invention.

Referring to FIG. 3, communication system 200 includes:
The difference from the communication system 100 described in FIG. 1 is that a decoding device 250 is provided instead of the decoding device 150.
The decoding device 250 includes a decoding processing circuit 260 and a surround signal generation circuit 280.

The decoding processing circuit 260 is similar to that of the first embodiment.
In addition to the decoding processing circuit 160 described above, a decoding processing circuit 165 for decoding signals X (C), X (L) and X (R) of channels other than the downmix signal included in the transmission signal. Further included. Accordingly, the decoding processing circuit 260 transmits the X (C), X (L), X (R), X
(Lo) and X (Ro) channel signals are output.

Surround signal generation circuit 280 receives signals of each channel output from decode processing circuit 260 and outputs surround signals X (SL) and X (SR). The surround signal generation circuit 280 outputs a signal of a surround channel based on the following equations (3) and (4) using the constant α used in the downmix circuit 120 in the encoding device.

X (SL) = X (Lo) −α × X (C) −X (L) (3) X (SR) = X (Ro) −α × X (C) −X (R) (4) By adopting such a configuration, even if transmission data having a recording format capable of efficiently decoding signals required for two-channel reproduction as described with reference to FIG. Can be decoded.

The configuration of encoding apparatus 110 in FIG. 3 is the same as that described in FIG. 1, and description thereof will not be repeated.

As described above, by performing communication of multi-channel signals in a recording format for directly encoding a signal that has been downmixed in advance, it is possible to reduce the cost and power consumption of a decoding device dedicated to 2-channel reproduction. Also, compatibility with audio equipment capable of multi-channel reproduction can be maintained. Therefore, an inexpensive popular version exclusively for 2-channel reproduction can be manufactured, and it is also possible to deal with a higher-level model that meets various consumer needs.

Next, an encoding procedure in the encoding apparatus described in the present invention will be described with reference to a flowchart.

FIG. 4 is a flowchart illustrating a method 300 for encoding a multi-channel signal according to the present invention. The encoding method 300 indicates an encoding method for each decoding unit.

Referring to FIG. 4, an encoding method 300 according to the present invention includes a step S10 of starting an encoding process for one decoding unit, a step S20 of downmixing a multi-channel signal, and a downmixing step. Encoding the encoded signal and a part of the multi-channel signal, and recording the encoded data for each decoding unit according to a predetermined format in step S40.
Ending the encoding process of one decoding unit
50.

The processing in step S20 corresponds to the operation of the downmix circuit 120 described with reference to FIG.
This is for performing downmixing based on the equation (2) and obtaining a 2-channel reproduction-only signal.

The processing in steps S30 and S40 corresponds to the operation of the encoding processing circuit 130 described with reference to FIG.
In step S30, the two-channel reproduction-only signal signal obtained by downmixing and a part of the multi-channel signal are independently encoded. The remaining multi-channel signals excluded from the encoding in step S30 can be combined at the time of decoding based on the equations (3) and (4) described above. In other words, in relation to the downmix operation formulas (formulas (1) and (2)), the channel signals to be encoded / not to be encoded so that all the original channel signals can be synthesized at the time of decoding at the time of decoding. Are selected respectively.

The recording format in step S40 is as described with reference to FIG. 2, and therefore the description will not be repeated.

By executing the encoding method according to such a procedure, a two-channel reproduction-only signal can be efficiently decoded from a multi-channel signal, and a decoding device corresponding to a two-channel reproduction-only device can be configured at low cost. Becomes possible.

In the embodiment of the present invention, M
The technique for efficiently obtaining a two-channel reproduction-only signal based on a five-channel multi-channel signal has been described by exemplifying the PEG-ACC method. However, the application of the present invention is limited to such a case. Instead, a similar procedure or configuration is used to efficiently convert an N-channel reproduction-only signal (N: a natural number of N <M) based on an M-channel (M: a natural number) multi-channel signal under another encoding method. Can be widely applied when obtaining

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0054]

According to the encoding method of the present invention, the two-channel reproduction-dedicated signal downmixed in advance and the other channel signals are encoded and recorded independently. Decoding capability can be suppressed, and a decoding device that executes decoding corresponding to a device dedicated to two-channel reproduction from data encoded by the encoding method can be configured at low cost.

The encoding method according to claim 2 employs a format for recording data corresponding to a two-channel reproduction-dedicated signal before data of other channel signals, so that the encoding method according to claim 1 is employed. In addition to the effect of
Decoding processing for obtaining a channel reproduction-only signal can be executed more efficiently.

According to the encoding method of the third aspect, the remaining two channel signals that have not been encoded can be synthesized by the two-channel reproduction-dedicated signal and the (N-2) other channel signals. In addition to the effect of the encoding method described in Item 1, it is possible to decode signals of all the original multi-channel signals without increasing the recording capacity.

According to the fourth aspect of the present invention, the two-channel reproduction-dedicated signal down-mixed in advance and the other channel signals are encoded and recorded independently, so that the decoding required to obtain the two-channel reproduced-only signal is performed. The processing capability can be suppressed, and a decoding device that executes decoding corresponding to a device dedicated to 2-channel reproduction from data encoded by the encoding device can be configured at low cost.

The encoding device according to claim 5 employs a format for recording data corresponding to a two-channel reproduction-only signal before data of other channel signals. In addition to the effects played,
A decoding process for obtaining a 2-channel reproduction-only signal from data encoded by the encoding device can be performed more efficiently.

According to the encoding apparatus of the present invention, the remaining two channel signals that have not been encoded can be synthesized by the two-channel reproduction-only signal and the (N-2) other channel signals. In addition to the effect of the encoding device described in Item 4, it is possible to decode signals of all the original multi-channel signals without increasing the recording capacity.

[0060] A communication system according to a seventh aspect of the present invention provides an encoding apparatus that encodes a two-channel reproduction-only signal and another channel signal that have been downmixed in advance and independently records them.
Since a decoding device specialized for decoding 2-channel reproduction-only signals is provided, a decoding device corresponding to 2-channel reproduction-only equipment can be configured at low cost.

The communication system according to the present invention includes an encoding device adopting a format for recording data corresponding to a two-channel reproduction-only signal before data of another channel signal. In addition to the effects provided by the communication system, decoding processing for obtaining a two-channel reproduction-only signal can be executed more efficiently.

According to a ninth aspect of the present invention, there is provided a communication system comprising a signal processing circuit capable of synthesizing the remaining two uncoded channel signals by a two-channel reproduction-only signal and (N-2) other channel signals. Since it is provided in the decoding device,
In addition to the effect provided by the communication system according to the seventh aspect, signals of all channels of the original multi-channel signal can be decoded without increasing the recording capacity.

[0063] The communication system according to claim 10 is an MPE.
In multi-channel transmission / reception in accordance with the D-ACC scheme, the effects of the communication system according to claim 9 can be enjoyed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a multi-channel communication system 100 capable of supporting two-channel reproduction according to a first embodiment.

FIG. 2 is a conceptual diagram illustrating a recording format for each audio decoding unit of transmission data according to the first embodiment.

FIG. 3 is a communication system 2 according to a modification of the first embodiment.
It is a block diagram explaining the structure of 00.

FIG. 4 is a flowchart illustrating a method 300 for encoding a multi-channel signal according to the present invention.

FIG. 5 is a conceptual diagram illustrating a five-channel speaker arrangement adopted in MPEG-ACC.

FIG. 6 is a conceptual diagram illustrating a conventional recording format of an audio code according to the MPEG-ACC system.

FIG. 7 is a block diagram showing a configuration of a conventional multi-channel signal communication system 500 capable of supporting two-channel reproduction.

[Explanation of symbols]

110 encoder, 120 downmix circuit, 1
30 encoding processing circuit, 150 decoding device, 160, 2
60 decode processing circuit, 280 surround signal generation circuit.

Claims (10)

[Claims] 1. An encoding method for encoding a multi-channel signal composed of N channel signals (N: a natural number of 3 or more), wherein the N channel signals are down-mixed to form a two-channel playback device. Generating a two-channel reproduction-only signal corresponding to: a step of independently encoding the two-channel reproduction-only signal and another channel signal; and converting the coded data for each decoding unit according to a predetermined format. Recording, wherein the recording step independently records encoded data respectively corresponding to the two-channel reproduction-only signal and the other channel signals. 2. The encoding according to claim 1, wherein said recording step records the encoded data corresponding to the two-channel reproduction-only signal before the encoded data corresponding to the other channel signal. Method. 3. The N channel signals include (N−2) other channel signals to be compression-encoded and the other two channel signals, and the other channel signals The encoding method according to claim 1, wherein a signal is selected such that the other two channel signals can be reproduced by synthesizing the other channel signal and the two-channel reproduction-only signal. 4. An encoding apparatus for encoding a multi-channel signal composed of N channel signals (N: a natural number of 3 or more), wherein the N channel signals are down-mixed to form a two-channel playback device. A downmix circuit for generating a two-channel reproduction-only signal corresponding to the above, and a code corresponding to each of the two-channel reproduction-only signal and the other channel signal by encoding the two-channel reproduction-only signal and another channel signal An encoding processing circuit that outputs a transmission data signal in which encoded data is independently recorded. 5. The encoding processing circuit generates the transmission data signal by recording the encoded data for each decoding unit according to a predetermined recording format. The encoding device according to claim 4, wherein the corresponding encoded data is recorded earlier than the encoded data corresponding to the other channel signal. 6. The encoding processing circuit encodes (N-2) other channel signals obtained by removing two channel signals from the multi-channel signal and the two-channel reproduction-dedicated signal. The method according to claim 4, wherein the other channel signal is selected such that the two channel signals are reproducible by combining the other channel signal and the two-channel reproduction-only signal. Encoding device. 7. A communication system for transmitting and receiving a multi-channel signal composed of N channel signals (N: a natural number of 3 or more), comprising: an encoding device for encoding the multi-channel signal; Comprises a downmix circuit for downmixing the N channel signals to generate a two-channel playback dedicated signal corresponding to a two-channel playback device; and encoding the two-channel playback dedicated signal and another channel signal. An encoding processing circuit that outputs a transmission data signal in which encoded data corresponding to each of the two-channel reproduction-only signal and the other channel signals is recorded independently, and decodes the transmission data signal to reproduce a reproduced audio signal. And a decoding device that outputs the two-channel reproduction-only signal. A communication system including a first decoding processing circuit for decoding encoded data. 8. The encoding processing circuit records the encoded data in accordance with a predetermined recording format for each decoding unit to generate the transmission data signal. The communication system according to claim 7, wherein the corresponding encoded data is recorded before the encoded data corresponding to the other channel signal. 9. The encoding processing circuit encodes (N-2) other channel signals obtained by removing two channel signals from the multi-channel signal and the two-channel reproduction-only signal. The other channel signal is selected such that the two channel signals that are not to be encoded can be reproduced by synthesizing the other channel signal and the two-channel reproduction-only signal. A decoding device that receives the transmission data signal and decodes encoded data corresponding to the other channel signal; and a decoding output of the first and second decoding processing devices. The communication system according to claim 7, further comprising: a signal processing circuit that receives the signal and outputs the two channel signals that have not been subjected to encoding. 10. The multi-channel signal is an MPE
10. The communication system according to claim 9, wherein the two channel signals that are G-AAC-compliant signals and are not subject to the encoding correspond to surround speaker audio signals.