CN1930914B - Method and device for encoding and synthesizing multi-channel audio signals - Google Patents

Abstract

For a multi-channel audio signal, audio coding is applied to different subsets of audio input channels of different frequency ranges. For example, for 5.1 surround sound with five regular channels and one Low Frequency (LFE) channel, Binaural Cue Coding (BCC) can be applied to the sub-bands of all six channels at or below a specified cut-off frequency, and only to the sub-bands of the five audio channels (excluding the LFE channel) above the cut-off frequency. Such frequency-based channel coding may reduce the burden of encoding and decoding processing operations and/or the size of the audio bitstream being encoded, as compared to parametric coding techniques that are applied to all input channels over the entire frequency range.

Description

Method and device for encoding and synthesizing multi-channel audio signals

technical field

The invention relates to the encoding of audio signals and the subsequent synthesis of auditory scenes from the encoded audio data. the

Cross References to Related Applications

This application claims priority on the filing date of U.S. Provisional Application No. 60/549972, filed March 4, 2004, with Attorney Docket No. Faller 14-2. The subject matter of this application is related to that of U.S. Patent Application Serial No. 09/848,877, filed May 4, 2001, in Attorney Docket No. Faller 5 (the "'877 application"), and filed Nov. 7, 2001, in Attorney Docket No. Baumgarte 1 -Subject of U.S. Patent Application Serial No. 10/045,458 filed May 24, 2002 under Attorney Docket Baumgarte 2-10 ("the '437 Application") filed on 6-8 (the "'458 Application") The subject of Serial No. 10/155,437, and the subject of U.S. Patent Application Serial No. 10/815,591, filed April 1, 2004, with Attorney Docket No. Baumgarte 7-12 (the "'591 application"), all of these four patent applications All are incorporated herein by reference. the

Background technique

Multichannel surround sound systems in movie theaters have been standardized for many years. As technology has advanced, it has become possible to manufacture multi-channel surround systems for home use. These days, such systems are often marketed as "home theater systems." Following ITU-R recommendations, most such systems provide five regular audio channels and a low-frequency subwoofer channel (meaning the low-frequency effects or LFE channel). Such a multi-channel system is denoted as a 5.1 surround system. There are other surround systems such as 7.1 (seven regular channels and one LFE channel) and 10.2 (ten regular channels and two LFE channels) surround systems. the

C.Faller and F.Baumgarte's paper "Efficient representation of spatial audio coding using perceptual parametrization", IEEE workshop on Appl. of Sig.Proc.to Audio and Acoust., October 2001, and C.Faller and F.Baumgart The contents of the paper "Binaural Cue Coding Applied to Stereo and Multi-Channel Audio Compression," Preprint 112th Conv.Aud.Eng.Soc., May 2002 (collectively "BCC Papers") are hereby incorporated by reference, to describe a parametric multi-channel audio coding technique (called BCC coding). the

Figure 1 shows a block diagram of an audio processing system 100 that performs binaural cue coding (BCC) according to the BCC paper. The BCC system 100 has a BCC encoder 102 that receives C audio input channels 108 , each channel eg from each of C different microphones 106 . The BCC encoder 102 has a down-mixer 110 which converts the C audio input channels into a single audio sum signal 112 . the

Additionally, the BCC encoder 102 has a BCC analyzer 114 which generates a BCC hint code data stream 116 for the C input channels. The BCC hint code (also called auditory scene parameter) includes inter-channel level difference (ICLD) and inter-channel time difference (ICTD) data for each input channel. The BCC analyzer 114 performs band-based processing to generate ICLD and ICTD data for each of one or more different sub-bands (eg, different critical bands) of the audio input channel. the

BCC encoder 102 sends summed signal 112 and BCC hint code data stream 116 (which may be, for example, in-band or out-of-band side information about the summed signal) to BCC decoder 104 of BCC system 100 . BCC decoder 104 has a side information processor 118 that processes data stream 116 to recover BCC hint codes 120 (eg, ICLD and ICTD data). The BCC decoder 104 also has a BCC synthesizer 122 which uses the recovered BCC hint code 120 to synthesize C audio output channels 124 from the summed signal 112 to be played through C speakers 126 respectively. the

The audio processing system 100 may be implemented in the environment of multi-channel audio signals such as 5.1 surround sound. In particular, the down-mixer 110 of the BCC encoder 102 converts the six input channels of conventional 5.1 surround sound (ie, five conventional channels plus one LFE channel) into a summed signal 112 . Additionally, the BCC analyzer 114 of the encoder 102 transforms the six input channels into the frequency domain to generate corresponding BCC hint codes 116 . Similarly, the side information processor 118 of the BCC decoder 104 recovers the BCC hint code 120 from the received side information stream 116, and the BCC synthesizer 122(1) of the decoder 104 then transforms the received summed signal 112 into In the frequency domain, (2) apply the recovered BCC cue code 120 to the summed signal in the frequency domain to produce six frequency domain signals, and then (3) transform these frequency domain signals into the six time domains of the synthesized 5.1 surround sound channels (ie, five synthesized regular channels plus one synthesized LFE channel) for playback through speaker 126. the

Contents of the invention

According to the present invention, there is provided:

A method of encoding a multi-channel audio signal having a plurality of audio input channels, the multi-channel audio signal having a plurality of conventional channels and at least one low-frequency effects channel, the method comprising: applying a parametric audio coding technique to producing parametric audio encoding for all audio input channels of a first frequency range corresponding to one or more sub-bands below a specified cutoff frequency; and applying the parametric audio encoding technique only for the first frequency range Parametric audio coding is produced by conventional channels of two frequency ranges, the second frequency range corresponding to one or more sub-bands above a specified cutoff frequency, where: for the first frequency range, parametric audio coding techniques generate parametric audio coding corresponding to Parametric audio coding of all audio input channels; and for the second frequency range, the parametric audio coding technique generates parametric audio coding corresponding only to regular channels, not to at least one low-frequency effects channel. the

Apparatus for encoding a multi-channel audio signal having a plurality of audio input channels, said multi-channel audio signal having a plurality of conventional channels and at least one low-frequency effects channel, comprising: applying a parametric audio coding technique to means for producing parametric audio coding for all audio input channels of a first frequency range corresponding to one or more sub-bands below a specified cut-off frequency; and applying parametric audio coding techniques only for Means for producing parametric audio coding on a regular channel of a second frequency range, said second frequency range corresponding to one or more sub-bands above a specified cut-off frequency, wherein: for a first frequency range, parametric audio coding The technique generates parametric audio coding corresponding to all audio input channels; and for the second frequency range, the parametric audio coding technique generates parametric audio coding corresponding only to conventional channels, not to at least one low-frequency effects channel. the

A parametric audio encoder comprising: a down-mixer adapted to generate one or more combined channels from a plurality of audio input channels of a multi-channel audio signal having a plurality of conventional channel and at least one low-frequency effects channel; and an analyzer for generating: (1) parametric audio encoding for all audio input channels in a first frequency range corresponding to one or more subbands of a specified cutoff frequency; and (2) parametric audio coding for regular channels only in a second frequency range corresponding to one or more subbands above the specified cutoff frequency subbands, where: for a first frequency range, the analyzer generates parametric audio encodings corresponding to all audio input channels; and for a second frequency range, the analyzer generates parametric audio encodings only for regular channels, not for at least one Parametric audio encoding of the low-frequency effects channel. the

A method of synthesizing a multi-channel audio signal having a plurality of audio output channels, the multi-channel audio signal having a plurality of conventional channels and at least one low-frequency effects channel, the method comprising: applying parametric audio decoding techniques to generate all audio output channels for a first frequency range corresponding to one or more sub-bands below a specified cutoff frequency; and applying parametric audio decoding techniques to generate only for a second frequency range , the second frequency range corresponds to one or more sub-bands above the specified cutoff frequency; where: parametric audio decoding techniques use parametric audio coding to generate audio output channels; for the first frequency range, the parametric The audio encoding corresponds to all audio output channels; and for the second frequency range, the parametric audio encoding corresponds only to the normal channels, not to the at least one low frequency effects channel. the

A device for synthesizing a multi-channel audio signal having a plurality of audio output channels, the multi-channel audio signal having a plurality of conventional channels and at least one low-frequency effect channel, the device comprising: applying parametric audio decoding techniques to generate means for all audio output channels of a first frequency range corresponding to one or more sub-bands below a specified cutoff frequency; and applying parametric audio decoding techniques to generate means of regular channels of frequency ranges, the second frequency range corresponding to one or more sub-bands above a specified cutoff frequency; wherein: parametric audio decoding techniques use parametric audio coding to generate audio output channels; for the first For the frequency range, the parametric audio coding corresponds to all audio output channels; and for the second frequency range, the parametric audio coding corresponds to only the normal channels, not to at least one low-frequency effects channel.

A parametric audio decoder for synthesizing a multi-channel audio signal with a plurality of audio output channels, the multi-channel audio signal having a plurality of conventional channels and at least one low-frequency effect channel, the parametric audio decoding The processor comprises: a side information processor adapted to recover parametric audio coding, and a synthesizer adapted to: apply parametric audio decoding techniques to generate all audio output channels for a first frequency range, said first frequency range corresponds to one or more sub-bands below the specified cutoff frequency; and applying parametric audio decoding techniques produces regular channels only for the second frequency range corresponding to frequencies above the specified cutoff frequency One or more frequency subbands; where: the parametric audio decoding technique generates audio output channels using parametric audio encoding; for the first frequency range, the parametric audio encoding corresponds to all audio output channels; and for the second frequency range, the parametric audio encoding The encoding corresponds only to the regular channels, not to at least one low-frequency effects channel. the

For surround sound applications, embodiments of the present invention relate to BCC-based parametric audio coding techniques, where band-based BCC coding is not applied to sub-bands above the cutoff frequency of the low-frequency subwoofer (LFE) channel. For example, for 5.1 surround sound, BCC coding is applied to sub-bands below the cutoff frequency of all six channels (that is, five conventional channels plus one LFE channel), while BCC coding is applied to only five conventional channels. The sub-band above the cutoff frequency of the channel (i.e. not applied to the LFE channel). By avoiding the application of BCC coding on the "high" frequencies of the LFE channel, these embodiments of the invention have (1) reduced Encoder and decoder processing burden and (2) smaller BCC coded bitstream. the

More generally, the present invention relates to the application of parametric audio coding techniques such as BCC coding, but not limited to BCC coding, in which two or more input channels are processed in two or more different frequency ranges. different subsets. As used in this specification, the term "subset" may refer to a set comprising all input channels as well as those suitable subsets comprising fewer than all input channels. The application of the present invention to BCC coding of 5.1 and other surround sound signals is only a special case of the present invention. the

Description of drawings

Other aspects, features and advantages of the present invention will be more apparent from the following detailed description, appended claims and accompanying drawings, wherein:

Figure 1 shows a block diagram of an audio processing system implementing a binaural cue code (BCC); and

FIG. 2 shows a block diagram of an audio processing system performing BCC encoding according to one embodiment of the present invention. the

Detailed ways

FIG. 2 shows a block diagram of an audio processing system 200 for performing binaural cue coding (BCC) for 5.1 surround sound according to an embodiment of the present invention. The BCC system 200 has a BCC encoder 202 that receives six audio input channels 208 (ie, five regular channels and one LFE channel). The BCC encoder 202 has a down-mixer 210 that converts (eg averages) the audio input channels (including the LFE channel) into one or more, but less than six, combined channels 212 . the

Additionally, the BCC encoder 202 has a BCC analyzer 214 which generates a BCC hint code data stream 216 for the input channels. As shown in FIG. 2, for subbands at or below a specified cutoff frequency _f , the BCC analyzer 214 uses all six 5.1 surround sound input channels (including the LFE channel) in generating the BCC cue code data . For all other (ie, high frequency) subbands, the BCC analyzer 214 uses only the five regular channels (the LFE channel is not used) to generate the BCC hint code data. As a result, the LFE channel contributes BCC codes only to the BCC subbands at or below the cutoff frequency, rather than to the entire BCC frequency range, thereby reducing the overall size of the side information bitstream.

The cutoff frequency is preferably chosen such that the effective audio bandwidth of the LFE channel is less than or equal to _fc (ie the LFE channel has practically no energy or actual audio content above the cutoff frequency). Unless the subband is tuned to the cutoff frequency, the cutoff frequency will fall within the particular subband. In this case, some subbands will exceed the cutoff frequency. For ease of illustration, such sub-bands are said to be "at" the cutoff frequency. In a preferred embodiment, the entire subband of the LFE channel is BCC coded, and the next higher frequency subband is the first high frequency subband that is not BCC coded.

In a possible implementation manner, the BCC prompt code includes inter-channel level difference (ICLD), inter-channel time difference (ICTD) and inter-channel correlation (ICC) data of input channels. The BCC analyzer 214 preferably performs band-based processing similar to that described in the '877 and '458 applications to generate ICLD and ICTD data for different sub-bands of the audio input channels. In addition, the BCC analyzer 214 preferably generates coherence measures as ICC data for the different subbands. These coherence measures are described in more detail in the '437 and '591 applications. the

BCC encoder 202 sends one or more combined channels 212 and a BCC hint code data stream 216 (eg, in-band or out-of-band side information about the combined channels) to BCC decoder 204 of BCC system 200 . BCC decoder 204 has a side information processor 218 that processes data stream 216 to recover BCC hint codes 220 (eg, ICLD, ICTD, and ICC data). The BCC decoder 204 also has a BCC synthesizer 222 which uses the recovered BCC cue code 220 to synthesize six audio output channels 224 from the one or more composite channels 212 for playback through the six surround sound speakers 226 respectively. the

As shown in FIG. 2 , BCC synthesizer 222 performs six-channel BCC synthesis of the subbands at or below the cutoff frequency _f , resulting in frequencies for all six 5.1 surround channels (i.e., including the LFE channel). content while performing five-channel BCC synthesis on subbands above the cutoff frequency, resulting in frequency content for only the five regular channels of 5.1 surround sound. In particular, the BCC synthesizer 222 decomposes the received combined channel 212 into a plurality of sub-bands (eg, critical bands). Different processing is applied in these subbands to obtain the corresponding subbands of the output audio channels. As a result, only subbands whose frequencies are at or below the cutoff frequency are acquired for the LFE channel. In other words, the LFE channel only has the frequency content of subbands at or below the cutoff frequency. The upper subbands of the LFE channel (ie those above the cutoff frequency) can be filled with null signals (if necessary).

Depending on the particular implementation, the BCC encoder can be designed to generate BCC hint codes for all frequencies, and simply not for specific sub-bands (e.g. sub-bands above the cut-off frequency and/or sub-bands with practically zero energy ) to send these prompt codes. Similarly, a corresponding BCC decoder can be designed to perform conventional BCC synthesis for all frequencies, where the BCC decoder applies appropriate BCC hint code values for those subbands that do not have an explicitly transmitted code. the

Although the present invention has been described in the context of a BCC decoder that applies the techniques described in the '877 and '458 applications to synthesize auditory scenes, the invention is also applicable to BCC decoders that employ other techniques to synthesize auditory scenes. case, without having to rely on the techniques described in the '877 and '458 applications. For example, the BCC processing of the present invention may be implemented without ICTD, ICLD and/or ICC data, with or without other suitable hint codes such as those associated with head-related transfer functions. the

In the embodiment of Figure 2, 5.1 surround sound is encoded by applying six-channel BCC analysis to sub-bands at or below the cut-off frequency and five-channel BCC analysis to sub-bands above the cut-off frequency. In another embodiment, the invention is applicable to 7.1 surround sound, where eight-channel BCC analysis is applied to sub-bands at or below a specified cutoff frequency, seven-channel BCC analysis (excluding the single LFE channel) is applied to subbands above the cutoff frequency. the

The invention is also applicable to surround sound with more than one LFE channel. For 10.2 surround sound for example, twelve-channel BCC analysis can be applied to subbands at or below the specified cutoff frequency, while ten-channel BCC analysis (with the two LFE channels excluded) can be applied above the cutoff frequency sub-band. Alternatively, two different cutoff frequencies can also be specified: a first cutoff frequency for the first LFE channel of 10.2 surround sound and a second cutoff frequency for the second LFE channel. In this case, assuming that the first cutoff frequency is lower than the second cutoff frequency, twelve-channel BCC analysis can be applied to subbands at or below the first cutoff frequency, while eleven-channel BCC analysis (excluding excluding the first LFE channel) to subbands that are (1) above the first cutoff frequency and (2) at or below the second cutoff frequency, and apply the ten-channel BCC analysis (excluding the two LFE channels ) is applied to subbands above the second cutoff frequency. the

Similarly, some consumer multi-channel devices are purposely designed to have different output channels with different frequency ranges. For example, some 5.1 surround sound equipment has two rear channels that are designed to reproduce only frequencies below 7kHz. The present invention is applicable to such systems by specifying two cutoff frequencies: one for the LFE channel and one higher for the rear channels. In this case, six-channel BCC analysis can be applied to subbands at or below the LFE cutoff frequency, and five-channel BCC analysis (excluding the LFE channel) can be applied to (1) above the LFE cutoff frequency and (2) sub-bands at or below the cut-off frequency of the rear channels, the three-channel BCC analysis (excluding the LFE channel and the two rear channels) can be applied to the sub-bands above the cut-off frequency of the rear channels. the

The invention can be further extended to apply parametric audio coding to two or more different subsets of input channels in two or more different frequency ranges, where parametric audio coding can be different from BCC coding, The different frequency ranges are chosen such that the frequency content of the different input channels is reflected within these ranges. Depending on the particular application, different channels may be excluded from different frequency ranges in any suitable combination. For example, low frequency channels may be excluded from the high frequency region and/or high frequency channels may be excluded from the low frequency region. It may even be the case that any single frequency range cannot encompass all input channels. the

As previously stated, while input channels 208 may be down-mixed to form a single combined (e.g., mono) channel 212, in alternative implementations, multiple input channels may be down-mixed, depending on the particular audio processing application. Mixing to form two or more different "combined" channels. More information on this technique can be found in US Patent Application No. 10/762,100, filed January 20, 04, the contents of which are incorporated herein by reference. the

In some implementations, when downmixing is performed to generate multiple combined channels, data for the combined channels may be transmitted using conventional audio transmission techniques. For example, when generating two combined channels, a conventional stereo transmission technique can be used. In this case, a BCC decoder can extract and use BCC encoding to synthesize a multi-channel signal (eg 5.1 surround sound) from two combined channels. Furthermore, this can provide backward compatibility where the two BCC synthesis channels are played back using a regular (ie non-BCC based) stereo decoder ignoring the BCC encoding. Similarly, a backwards-compatibility implementation can be used with a single decoder for conventional tracks when producing a single BCC composite channel. Note that, theoretically, when there are multiple "combined" channels, one or more of these combined channels could actually be based on separate input channels. the

While the BCC system 200 may have the same number of audio input channels as audio output channels, in alternative embodiments, the number of input channels may be greater or less than the number of output channels depending on the particular application. For example, the input audio may correspond to 7.1 surround sound, while the synthesized output audio may correspond to 5.1 surround sound, or vice versa. the

In general, the implementation of the BCC encoder of the present invention can be based on the case of converting M input audio channels into N combined channels and one or more corresponding BCC coded subsets, where M>N ≥1. Similarly, the realization of the BCC decoder of the present invention can also be based on the fact that P output channels and corresponding BCC coding subsets are generated from N combined audio channels, where P>N, and P can It can be the same as M or different. the

Depending on the particular implementation, the various signals received by and generated by both BCC encoder 202 and BCC decoder 204 of FIG. 2 may be any suitable combination of analog and/or digital signals, including all analog signals or all digital signal. Although not shown in FIG. 2 , those skilled in the art can understand that one or more composite channels 212 and the BCC prompt code data stream 116 can be further encoded by the BCC encoder 202 and correspondingly encoded by the BCC decoder 204. The decoding of , eg based on some suitable compression mechanism (eg ADPCM), further reduces the size of the transmitted data. the

The definition of data transfer from BCC encoder 202 to BCC decoder 204 depends on the particular application of audio processing system 200 . For example, in some embodiments, such as a live broadcast of a concert, transmission may involve real-time transmission of data for immediate playback at a remote location. In other applications, "transfer" may involve storage of data to a CD or other suitable storage medium for later (ie, non-real-time) playback. Of course, other applications are also possible. the

Depending on the particular implementation, the transport channel can be wired or wireless, and custom or standardized protocols (eg, IP) can be used. Media such as CDs, DVDs, digital tape recorders, and solid-state memory can be used for storage. Furthermore, transmission and/or storage may, but need not, include channel coding. Similarly, although the present invention has been described in terms of digital audio systems, those skilled in the art will appreciate that the present invention can also be practiced in the context of analog audio systems, such as AM radio, FM radio, and analog television broadcasting. In the audio part, all of the above support the introduction of additional in-band low bit rate transmission channels. the

Implementations of the present invention can also be used in many different applications, such as music reproduction, broadcasting and telephony. For example, implementations of the present invention may also be used with digital radio/television/Internet (eg, webcast) broadcasts, such as Sirius Satellite Broadcasting or XM Satellite Broadcasting. Other applications include Voice over IP, PSTN or other voice networks, analog radio broadcasting and Internet broadcasting. the

Depending on the specific application, different techniques can be used to embed the set of BCC codes into the combined channel to obtain the BCC signal of the present invention. The feasibility of any particular technique may depend, at least in part, on the particular transmission/storage medium used for the BCC signal. For example, digital radio broadcast protocols often support the inclusion of additional enhancement bits (eg, in the header portion of data packets) that are ignored by conventional receivers. These additional bits can be used to represent the set of auditory scene parameters to provide a BCC signal. In general, any suitable technique may be used in the implementation of the present invention to mark the audio signal, wherein data corresponding to a set of auditory scene parameters is embedded into the audio signal to form a BCC signal. For example, these techniques may involve data hidden under a perceptual masking curve or data hidden in pseudorandom noise. Pseudorandom noise feels like smooth noise. Data embedding can also be implemented for in-band signaling using a bit-snatching approach similar to that employed in TDM (Time Division Multiplexing) transmission. Another possible technique is μ-law LSB bit flipping, where the least significant bit is used to transmit data. the

The invention may be implemented in circuit-based processing, including possible implementations on a single integrated circuit. It will be apparent to those skilled in the art that various functions of circuit elements may also be implemented by processing steps in a software program. Such software can be used, for example, in digital signal processors, microcontrollers or general purpose computers. the

The present invention can be embodied in the form of these methods and apparatuses for carrying out these methods. The present invention can also be embodied in the form of program code contained in a tangible medium such as a floppy disk, CD-ROM, hard disk or any other machine-readable storage medium, wherein when the program code is loaded into a machine such as a computer and When executed, the machine becomes a means for implementing the invention. The present invention can also be embodied in the form of program code, for example, stored in a storage medium, loaded into a machine and/or executed by a machine, or transmitted through some transmission medium or carrier, such as on an electric wire or cable. , through optical fiber, or via electromagnetic radiation, wherein when the program code is loaded into a machine such as a computer and executed, the machine becomes a means for implementing the present invention. When implemented on a general-purpose processor, the program code segments cooperate with the processor to provide a unique device that operates like specific logic circuits. the

It should also be understood that details, materials and arrangements of parts which have been described and shown for the purpose of illustrating the nature of the invention can be changed by those skilled in the art without departing from the scope of the invention as expressed in the following claims Change it below. the

Claims (16)

1. the multi-channel audio signal with a plurality of audio frequency input sound channels is carried out Methods for Coding, said multi-channel audio signal has a plurality of conventional sound channels and at least one low-frequency effect sound channel, and this method comprises:

Application parameter audio coding technology produces parametric audio coding for all audio frequency input sound channels that are used for first frequency range, and said first frequency range is corresponding to being lower than one or more sub-bands of specifying cut-off frequency; And

Application parameter audio coding technology only produces parametric audio coding for the conventional sound channel that is used for second frequency range, and said second frequency range is corresponding to being higher than one or more sub-bands of specifying cut-off frequency, wherein:

For first frequency range, the parametric audio coding technology generates the parametric audio coding corresponding to all audio frequency input sound channels; And

For second frequency range, the parametric audio coding technology generates only corresponding to conventional sound channel, and is not directed against the parametric audio coding of at least one low-frequency effect sound channel.

2. according to the process of claim 1 wherein that the parametric audio coding technology is a dual track keying BCC coding, and said parametric audio coding is the BCC sign indicating number.

3. according to the process of claim 1 wherein that cut-off frequency is effective audio bandwidth of low-frequency effect sound channel at least.

4. according to the process of claim 1 wherein that multi-channel audio signal is 5.1 surround sound signals.

5. according to the method for claim 1, also comprise and transmit the parametric audio coding that is used for first and second frequency ranges.

6. the multi-channel audio signal with a plurality of audio frequency input sound channels is carried out apparatus for encoding, said multi-channel audio signal has a plurality of conventional sound channels and at least one low-frequency effect sound channel, and this device comprises:

Application parameter audio coding technology is the device that is used for all audio frequency input sound channels generation parametric audio codings of first frequency range, and said first frequency range is corresponding to being lower than one or more sub-bands of specifying cut-off frequency; And

Application parameter audio coding technology only produces the device of parametric audio coding for the conventional sound channel that is used for second frequency range, said second frequency range is corresponding to being higher than one or more sub-bands of specifying cut-off frequency, wherein:

For first frequency range, the parametric audio coding technology generates the parametric audio coding corresponding to all audio frequency input sound channels; And

For second frequency range, the parametric audio coding technology generates only corresponding to conventional sound channel, and is not directed against the parametric audio coding of at least one low-frequency effect sound channel.

7. parametric audio coders comprises:

Be applicable to the down-conversion mixer that is produced one or more combined channels by a plurality of audio frequency input sound channels of multi-channel audio signal, said multi-channel audio signal has a plurality of conventional sound channels and at least one low-frequency effect sound channel; And

Analyzer is used for producing:

(1) be used for the parametric audio coding of all the audio frequency input sound channels in first frequency range, said first frequency range is corresponding to being lower than one or more sub-bands of specifying cut-off frequency; And

(2) only be used for the parametric audio coding of the conventional sound channel in second frequency range, said second frequency range is corresponding to being higher than one or more sub-bands of specifying cut-off frequency, wherein:

For first frequency range, analyzer generates the parametric audio coding corresponding to all audio frequency input sound channels; And

For second frequency range, analyzer generates only corresponding to conventional sound channel, and is not directed against the parametric audio coding of at least one low-frequency effect sound channel.

8. according to the parametric audio coders of claim 7, wherein parametric audio coding is the BCC coding.

9. according to the parametric audio coders of claim 7, also comprise being applicable to the parametric audio coding that transmits first and second frequency ranges.

10. the method for the multi-channel audio signal with a plurality of audio frequency output channels being synthesized, said multi-channel audio signal have a plurality of conventional sound channels and at least one low-frequency effect sound channel, and this method comprises:

Application parameter audio decoder technology produces all audio frequency output channels that are used for first frequency range, and said first frequency range is corresponding to being lower than one or more sub-bands of specifying cut-off frequency; And

Application parameter audio decoder technology only produces the conventional sound channel that is used for second frequency range, and said second frequency range is corresponding to being higher than one or more sub-bands of specifying cut-off frequency; Wherein:

Parametric audio decoding technique operation parameter audio coding generates the audio frequency output channels;

For first frequency range, parametric audio coding is corresponding to all audio frequency output channels; And

For second frequency range, parametric audio coding is only corresponding to conventional sound channel, and at least one low-frequency effect sound channel.

11. according to the method for claim 10, wherein the parametric audio decoding technique is the BCC decoding.

12. according to the method for claim 10, wherein cut-off frequency is effective audio bandwidth of low-frequency effect sound channel at least.

13. according to the method for claim 10, wherein multi-channel audio signal is 5.1 surround sound signals.

14. to the device that the multi-channel audio signal with a plurality of audio frequency output channels synthesizes, said multi-channel audio signal has a plurality of conventional sound channels and at least one low-frequency effect sound channel, this device comprises:

Application parameter audio decoder technology produces the device of all audio frequency output channels that are used for first frequency range, and said first frequency range is corresponding to being lower than one or more sub-bands of specifying cut-off frequency; And

Application parameter audio decoder technology produces the device of the conventional sound channel that only is used for second frequency range, and said second frequency range is corresponding to being higher than one or more sub-bands of specifying cut-off frequency; Wherein:

Parametric audio decoding technique operation parameter audio coding generates the audio frequency output channels;

For first frequency range, parametric audio coding is corresponding to all audio frequency output channels; And

For second frequency range, parametric audio coding is only corresponding to conventional sound channel, and at least one low-frequency effect sound channel.

15. a parametric audio decoder is used for synthetic multi-channel audio signal with a plurality of audio frequency output channels, said multi-channel audio signal has a plurality of conventional sound channels and at least one low-frequency effect sound channel, and said parametric audio decoder comprises:

The side information processor, it is applicable to the recovery parametric audio coding, and

Synthesizer, it is suitable for:

Application parameter audio decoder technology produces all audio frequency output channels that are used for first frequency range, and said first frequency range is corresponding to being lower than one or more sub-bands of specifying cut-off frequency; And

Application parameter audio decoder technology produces the conventional sound channel that only is used for second frequency range, and said second frequency range is corresponding to being higher than one or more sub-bands of specifying cut-off frequency; Wherein:

Parametric audio decoding technique operation parameter audio coding generates the audio frequency output channels;

For first frequency range, parametric audio coding is corresponding to all audio frequency output channels; And

For second frequency range, parametric audio coding is only corresponding to conventional sound channel, and at least one low-frequency effect sound channel.

16. according to the parametric audio decoder of claim 15, wherein parametric audio coding is the BCC coding.

Images