WO2005036925A2 - Compatible multi-channel coding/decoding - Google Patents

Compatible multi-channel coding/decoding Download PDF

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Publication number
WO2005036925A2
WO2005036925A2 PCT/EP2004/010948 EP2004010948W WO2005036925A2 WO 2005036925 A2 WO2005036925 A2 WO 2005036925A2 EP 2004010948 W EP2004010948 W EP 2004010948W WO 2005036925 A2 WO2005036925 A2 WO 2005036925A2
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Prior art keywords
channel
downmix
side information
original
channels
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PCT/EP2004/010948
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French (fr)
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WO2005036925A3 (en
Inventor
Juergen Herre
Johannes Hilpert
Stefan Geyersberger
Andreas Hoelzer
Claus Spenger
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Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.
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Priority to BR122018069728-8A priority Critical patent/BR122018069728B1/en
Priority to CA2540851A priority patent/CA2540851C/en
Priority to NO20191058A priority patent/NO347074B1/en
Priority to BR122018069726-1A priority patent/BR122018069726B1/en
Priority to BR122018069731-8A priority patent/BR122018069731B1/en
Priority to EP04787072A priority patent/EP1668959B1/en
Priority to AU2004306509A priority patent/AU2004306509B2/en
Priority to MXPA06003627A priority patent/MXPA06003627A/en
Priority to BR122018069730-0A priority patent/BR122018069730B1/en
Priority to DK04787072T priority patent/DK1668959T3/en
Priority to JP2006530060A priority patent/JP4547380B2/en
Application filed by Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. filed Critical Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V.
Priority to CN2004800287769A priority patent/CN1864436B/en
Priority to DE602004004168T priority patent/DE602004004168T2/en
Priority to BRPI0414757A priority patent/BRPI0414757B1/en
Publication of WO2005036925A2 publication Critical patent/WO2005036925A2/en
Publication of WO2005036925A3 publication Critical patent/WO2005036925A3/en
Priority to IL174286A priority patent/IL174286A/en
Priority to NO20061898A priority patent/NO342804B1/en
Priority to HK06113564A priority patent/HK1092001A1/en
Priority to NO20180978A priority patent/NO344635B1/en
Priority to NO20180980A priority patent/NO344483B1/en
Priority to NO20180990A priority patent/NO344760B1/en
Priority to NO20180991A priority patent/NO344091B1/en
Priority to NO20180993A priority patent/NO344093B1/en
Priority to NO20200106A priority patent/NO345265B1/en

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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
    • H04S3/02—Systems employing more than two channels, e.g. quadraphonic of the matrix type, i.e. in which input signals are combined algebraically, e.g. after having been phase shifted with respect to each other
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
    • G10L19/008—Multichannel audio signal coding or decoding using interchannel correlation to reduce redundancy, e.g. joint-stereo, intensity-coding or matrixing
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10L—SPEECH ANALYSIS TECHNIQUES OR SPEECH SYNTHESIS; SPEECH RECOGNITION; SPEECH OR VOICE PROCESSING TECHNIQUES; SPEECH OR AUDIO CODING OR DECODING
    • G10L19/00—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis
    • G10L19/02—Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis using spectral analysis, e.g. transform vocoders or subband vocoders
    • G10L19/032—Quantisation or dequantisation of spectral components
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S3/00—Systems employing more than two channels, e.g. quadraphonic
    • H04S3/008—Systems employing more than two channels, e.g. quadraphonic in which the audio signals are in digital form, i.e. employing more than two discrete digital channels
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
    • H04S2400/03—Aspects of down-mixing multi-channel audio to configurations with lower numbers of playback channels, e.g. 7.1 -> 5.1
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S2420/00—Techniques used stereophonic systems covered by H04S but not provided for in its groups
    • H04S2420/03—Application of parametric coding in stereophonic audio systems

Definitions

  • a recommended multi-channel- surround representation includes, in addition to the two stereo channels L and R, an additional center channel C and two surround channels Ls, Rs.
  • This reference sound format is also referred to as three/two-stereo, which means three front channels and two surround channels.
  • five transmission channels are required.
  • at least five speakers at the respective five different places are needed to get an optimum sweet spot in a certain distance from the five well-placed loudspeakers.
  • Intensity stereo coding is described in AES preprint 3799, "Intensity Stereo Coding", J. Herre, K. H. Brandenburg, D. Lederer, February 1994, Amsterdam.
  • intensity stereo is based on a main axis transform to be applied to the data of both stereophonic audio channels. If most of the data points are concentrated around the first principle axis, a coding gain can be achieved by rotating both signals by a certain angle prior to coding. This is, however, not always true for real stereophonic production techniques. Therefore, this technique is modified by excluding the second orthogonal component from transmission in the bit stream.
  • the reconstructed signals for the left and right channels consist of differently weighted or scaled versions of the same transmitted signal.
  • the BCC technique is described in AES convention paper 5574, "Binaural cue coding applied to stereo and multi- channel audio compression", C. Faller, F. Baumgarte, May 2002, Kunststoff.
  • BCC encoding a number of audio input channels are converted to a spectral representation using a DFT based transform with overlapping windows. The resulting uniform spectrum is divided into non-overlapping partitions each having an index. Each partition has a bandwidth proportional to the equivalent rectangular bandwidth (ERB) .
  • the inter-channel level differences (ICLD) and the inter- channel time differences (ICTD) are estimated for each partition for each frame k.
  • the ICLD and ICTD are quantized and coded resulting in a BCC bit stream.
  • the inter-channel level differences and inter-channel time differences are given for each channel relative to a reference channel. Then, the parameters are calculated in accordance with prescribed formulae, which depend on the certain partitions of the signal to be processed.
  • intensity stereo coding therefore, a group of independent original channel signals is transmitted within a single portion of "carrier" data.
  • the decoder then reconstructs the involved signals as identical data, which are rescaled according to their original energy-time envelopes. Consequently, a linear combination of the transmitted channels will lead to results, which are quite different from the original downmix.
  • a drawback is that the stereo- compatible downmix channels Lc and Re are derived not from the original channels but from intensity stereo coded/decoded versions of the original channels. Therefore, data losses because of the intensity stereo coding system are included in the compatible downmix channels.
  • Astereo- only decoder which only decodes the compatible channels rather than the enhancement intensity stereo encoded channels, therefore, provides an output signal, which is affected by intensity stereo induced data losses.
  • this object is achieved by a method of processing a multi-channel audio signal, the multi-channel audio signal having at least three original channels, comprising: providing a first downmix channel and a second downmix channel, the first and the second downmix channels being derived from the original channels; calculating channel side information for a selected original channel of the original signals such that a downmix channel or a combined downmix channel including the first and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel; and generating output data, the output data including the chan- nel side information, the first downmix channel or a signal derived from the first downmix channel and the second down- mix channel or a signal derived from the second downmix channel.
  • this object is achieved by an apparatus for inverse processing of input data, the input data including channel side information, a first downmix channel or a signal derived from the first downmix channel and a second downmix channel or a signal derived from the second downmix channel, wherein the first downmix channel and the second downmix channel are derived from at least three original channels of a multi-channel audio signal, and wherein the channel side information are calculated such that a downmix channel or a combined downmix channel including the first downmix channel and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel
  • the apparatus comprising: an input data reader for reading the input data to obtain the first downmix channel or a signal derived from the first downmix channel and the second downmix channel or a signal derived from the second downmix channel and the channel side information; and a channel reconstructor for reconstructing the approximation of the selected original channel using the channel side information and the downmix channel or the combined downmix
  • the inventive concept is advantageous in that it provides a bit-efficient multi-channel extension such that a multichannel audio signal can be played at a decoder.
  • the present invention is advantageous in that it is bit- efficient, since, in contrast to the prior art, no additional carrier channel beyond the first and second downmix channels Lc, Re is required. Instead, the channel side in- formation are related to one or both downmix channels. This means that the downmix channels themselves serve as a carrier channel, to which the channel side information are combined to reconstruct an original audio channel. This means that the channel side information are preferably pa- rar ⁇ etric side information, i.e., information which do not include any subband samples or spectral coefficients. Instead, the parametric side information are information used for weighting (in time and/or frequency) the respective downmix channel or the combination of the respective down- mix channels to obtain a reconstructed version of a selected original channel.
  • channel information for the original center channel are derived using the first downmix channel as well as the second downmix channel, i.e., using a combination of the two downmix channels.
  • this combination is a summation.
  • the groupings i.e., the relation between the channel side information and the carrier signal, i.e., the used downmix channel for providing channel side information for a selected original channel are such that, for optimum quality, a certain downmix channel is selected, which contains the highest possible relative amount of the respec- tive original multi-channel signal which is represented by means of channel side information.
  • the first and the second downmix channels are used.
  • the sum of the first and the second downmix channels can be used.
  • the sum of the first and second downmix channels can be used for calculating channel side information for each of the original channels.
  • the sum of the downmix channels is used for calculating the channel side information of the original center channel in a surround environment, such as five channel surround, seven channel surround, 5.1 surround or 7.1 surround.
  • a surround environment such as five channel surround, seven channel surround, 5.1 surround or 7.1 surround.
  • Using the sum of the first and second downmix channels is especially advantageous, since no additional transmission overhead has to be performed. This is due to the fact that both downmix channels are pre- sent at the decoder such that summing of these downmix channels can easily be performed at the decoder without requiring any additional transmission bits.
  • the channel side information forming the multi- channel extension are input into the output data bit stream in a compatible way such that a lower scale decoder simply ignores the multi-channel extension data and only provides a stereo representation of the multi-channel audio signal. Nevertheless, a higher scale encoder not only uses two downmix channels, but, in addition, employs the channel side information to reconstruct a full multi-channel representation of the original audio signal.
  • the right downmix channel and the channel side information for the right channel are used.
  • the left downmix channel and the channel side information for the left surround channel are used.
  • the channel side information for the right surround channel and the right downmix channel are used.
  • a combined channel formed from the first downmix channel and the second downmix channel and the center channel side information are used.
  • the first and second downmix channels as the left and right channels such that only three sets (out of e. g. five) of channel side information parameters have to be transmitted.
  • This is, however, only advisable in situations, where there are less stringent rules with respect to quality. This is due to the fact that, normally, the left downmix channel and the right downmix channel are different from the original left channel or the original right channel. Only in situations, where one can not afford to transmit channel side information for each of the original channels, such processing is advantageous.
  • Fig. 1 is a block diagram of a preferred embodiment of the inventive encoder
  • Fig. 2 is a block diagram of a preferred embodiment of the inventive decoder
  • Fig. 3A is a block diagram for a preferred implementation of the means for calculating to obtain frequency selective channel side information
  • Fig. 3B is a preferred embodiment of a calculator imple- menting joint stereo processing such as intensity coding or binaural cue coding;
  • Fig, 4 illustrates another preferred embodiment of the means for calculating channel side information, in which the channel side information are gain factors;
  • Fig. 5 illustrates a preferred embodiment of an implementation of the decoder, when the encoder is implemented as in Fig. 4;
  • Fig. 6 illustrates a preferred implementation of the means for providing the downmix channels
  • Fig. 7 illustrates groupings of original and downmix channels for calculating the channel side infor- ation for the respective original channels
  • Fig. 8 illustrates another preferred embodiment of an inventive encoder
  • Fig. 9 illustrates another implementation of an inventive decoder
  • Fig. 10 illustrates a prior art joint stereo encoder.
  • Fig. 1 shows an apparatus for processing a multi-channel audio signal 10 having at least three original channels such as R, L and C.
  • the original audio signal has more than three channels, such as five channels in the surround environment, which is illustrated in Fig. 1.
  • the five channels are the left channel L, the right channel R, the center channel C, the left surround channel Ls and the right surround channel Rs .
  • the inventive apparatus includes means 12 for providing a first downmix channel Lc and a second downmix channel Re, the first and the second downmix channels being derived from the original channels.
  • Lc and Re For deriving the downmix channels from the original channels, there exist several possibilities.
  • One possibility is to derive the downmix channels Lc and Re by means of matrixing the original channels using a matrixing operation as illus- trated in Fig. 6. This matrixing operation is performed in the time domain.
  • the matrixing parameters a, b and t are selected such that they are lower than or equal to 1.
  • a and b are 0.7 or 0.5.
  • the overall weighting parameter t is preferably chosen such that channel clipping is avoided. .
  • the downmix channels l>c and Re can also be externally supplied. This may be done, when the downmix channels Lc and Re are the result of a "hand mixing" operation.
  • a sound engineer mixes the downmix channels by himself rather than by using an automated matrixing operation. The sound engineer performs creative mixing to get optimized downmix channels Lc and Re which give the best possible stereo rep- resentation of the original multi-channel audio signal.
  • the means for providing does not perform a matrixing operation but simply forwards the externally supplied downmix chan- nels to a subsequent calculating means 14.
  • the means for calculating channel side information is further operative to calculate the channel side information for a selected original channel such that a combined downmix channel including a combination of the first and second downmix channels, when weighted using the calculated channel side information results in an approximation of the selected original channel.
  • an adder 14a and a combined channel side information calculator 14b are shown.
  • the decoder input data are input into a data stream reader 24 for reading the input data to finally obtain the channel side information 26 and the left downmix channel 28 and the right downmix channel 30.
  • the data stream reader 24 also includes an audio decoder, which is adapted to the audio encoder used for encoding the downmix channels.
  • the audio decoder which is part of the data stream reader 24, is op- erative to generate the first downmix channel Lc and the second downmix channel Re, or, stated more exactly, a decoded version of those channels.
  • signals and decoded versions thereof is only made where explicitly stated.
  • the channel side information 26 and the left and right downmix channels 28 and 30 output by the data stream reader 24 are fed into a multi-channel reconstructor 32 for providing a reconstructed version 34 of the original audio signals, which can be played by means of a multi-channel player 36.
  • the multi-channel reconstructor is operative in the frequency domain, the multi-channel player 36 will receive frequency domain input data, which have to be in a certain way decoded such as converted into the time domain before playing them.
  • the multi-channel player 36 may also include decoding facilities.
  • a lower scale decoder will only have the data stream reader 24, which only outputs the left and right downmix channels 28 and 30 to a stereo output 38.
  • An enhanced inventive decoder will, however, extract the channel side information 26 and use these side information and the downmix channels 28 and 30 for reconstructing reconstructed versions 34 of the original channels using the multi-channel reconstructor 32.
  • Fig. 3A shows an embodiment of the inventive calculator 14 for calculating the channel side information, which an audio encoder on the one hand and the channel side information calculator on the other hand operate on the same spectral representation of multi-channel signal.
  • Fig. 1 shows the other alternative, in which the audio en- coder on the one hand and the channel side information calculator on the other hand operate on different spectral representations of the multi-channel signal.
  • the Fig. 1 alternative is preferred, since filterbanks individually optimized for audio encoding and side information calculation can be used.
  • the Fig. 3A alternative is preferred, since this alternative requires less computing power because of a shared utilization of elements.
  • the device shown in Fig. 3A is operative for receiving two channels A, B.
  • the device shown in Fig. 3A is operative to calculate a side information for channel B such that using this channel side information for the selected original channel B, a reconstructed version of channel B can be calculated from the channel signal A.
  • the device shown in Fig. 3A is operative to form frequency domain channel side information, such as parameters for weighting (by multiplying or time processing as in BCC coding e. g. ) spectral values or subband samples.
  • the inventive calculator includes windowing and time/frequency conversion means 140a to obtain a frequency representation of channel A at an output 140b or a frequency domain representation of channel B at an output 140c.
  • the frequency domain representation of channel A which is preferably already quantized can then be directly used for entropy encoding using an entropy encoder 14Og, which may be a Huffman based encoder or an entropy encoder implementing arithmetic encoding.
  • the output of the device in Fig. 3A is the side information such as lj . for one original channel (corresponding to the side information for B at the output of device 140f) .
  • the entropy encoded bitstream for channel A corresponds to e. g. the encoded left downmix channel Lc' at the output of block 16 in Fig. 1.
  • element 14 (Fig. 1) i.e., the calculator for calculating the channel side information and the audio encoder 16 (Fig. 1) can be implemented as separate means or can be implemented as a shared version such that both devices share several elements such as the MDCT filter bank 140a, the quantizer 140e and the entropy encoder 140g.
  • the encoder 16 and the calculator 14 (Fig. 1) will be implemented in different devices such that both elements do not share the filter bank etc.
  • the actual deter inator for calculating the side information may be implemented as a joint stereo module as shown in Fig.3B, which operates in accordance with any of the joint stereo techniques such as intensity stereo coding or binaural cue coding.
  • the inventive determination means 140f does not have to calculate the combined channel.
  • the "combined channel” or carrier channel as one can say, already exists and is the left compatible downmix channel Lc or the right compatible downmix channel Re or a combined version of these downmix channels such as Lc + Re.
  • the inventive device 14Of only has to calculate the scaling information for scaling the respective downmix channel such that the en- ergy/time envelope of the respective selected original channel is obtained, when the downmix channel is weighted using the scaling information or, as one can say, the intensity directional information.
  • the joint stereo module 140f in Fig 3B is illustrated such that it receives, as an input, the "combined" channel A, which is the first or second downmix channel or a combination of the downmix channels, and the original selected channel.
  • This module naturally, outputs the "com- bined" channel A and the joint stereo parameters as channel side information such that, using the combined channel A and the joint stereo parameters, an approximation of the original selected channel B can be calculated.
  • the joint stereo module 140f can be implemented for performing binaural cue coding.
  • the joint stereo module 140f is operative to output the channel side information such that the channel side information are quantized and encoded ICLD or ICTD parameters, wherein the selected original channel serves as the actual to be processed channel, while the respective downmix channel used for calculating the side in- formation, such as the first, the second or a combination of the first and second downmix channels is used as the reference channel in the sense of the BCC coding/decoding technique.
  • This device includes a frequency band selector 44 selecting a frequency band from channel A and a corresponding frequency band of channel B. Then, in both frequency bands, an energy is calculated by means of an energy calculator 42 for each branch.
  • the detailed implementation of the energy calculator 42 will depend on whether the output signal from block 40 is a sub- band signal or are frequency coefficients. In other imple- mentations, where scale factors for scale factor bands are calculated, one can already use scale factors of the first and second channel A, B as energy values E a and E B or at least as estimates of the energy.
  • the decoder has to calculate the actual energy of the downmix channel and the gain factor based on the downmix channel energy and the transmitted energy for channel B.
  • the decoded downmix channel Lc or Re is not played back in a multi-channel enhanced decoder.
  • the decoded downmix channels are only used for reconstructing the original channels.
  • the decoded downmix channels are only replayed in lower scale stereo-only decoders.
  • FIG. 9 shows the preferred implementation of the present invention in a sur- round/mp3 environment.
  • An mp3 enhanced surround bitstream is input into a standard mp3 decoder 24, which outputs decoded versions of the original downmix channels. These downmix channels can then be directly replayed by means of a low level decoder. Alternatively, these two channels are input into the advanced joint stereo decoding device 32 which also receives the multi-channel extension data, which are preferably input into the ancillary data field in a mp3 compliant bitstream.
  • Fig. 7 showing the grouping of the selected original channel and the respective downmix channel or combined downmix channel.
  • the right column of the table in Fig. 7 corresponds to channel A in Fig. 3A, 3B, 4 and 5, while the column in the middle corresponds to channel B in these figures.
  • the respective channel side information is explicitly stated.
  • the channel side information li for the original left channel L is calculated using the left downmix channel Lc.
  • the left surround channel side information lsi is determined by means of the original selected left surround channel Ls and the left downmix channel Lc is the carrier.
  • the right channel side information i for the original right channel R are determined using the right downmix channel Re. Additionally, the channel side information for the right surround channel Rs are determined using the right downmix channel Re as the carrier. Finally, the channel side information ci for the center channel C are deter- mined using the combined downmix channel, which is obtained by means of a combination of the first and the second down- mix channel, which can be easily calculated in both an encoder and a decoder and which does not require any extra bits for transmission.
  • the channel side information for the left channel e. g. based on a combined down- mix channel or even a downmix channel, which is obtained by a weighted addition of the first and second downmix chan- nels such as 0.7 Lc and 0.3 Re, as long as the weighting parameters are known to a decoder or transmitted accordingly.
  • a normal encoder needs a bit rate of 64 kbit/s for each channel amounting to an overall bit rate of 320 kbit/s for the five channel signal.
  • the left and right stereo signals require a bit rate of 128 kbit/s.
  • Channels side information for one channel are between 1.5 and 2 kbit/s. Thus, even in a case, in which channel side information for each of the five channels are transmitted, this additional data add up to only 7.5 to 10 kbit/s.

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Abstract

In processing a multi-channel audio signal having at least three original channels, a first downmix channel and a second downmix channel are provided (12), which are derived from the original channels. For a selected original channel of the original channels, channel side information are calculated (14) such that a downmix channel or a combined downmix channel including the first and the second downmix channels, when weighted using the channel side information, results in an approximation of the selected original channel. The channel side information and the first and second downmix channels form output data (20) to be transmitted to a decoder, which, in case of a low level decoder only decodes the first and second downmix channels or, in case of a high level decoder provides a full multi-channel audio signal based on the downmix channels and the channel side information. Since the channel side information only occupy a low number of bits, and since the decoder does not use dematrixing, an efficient and high quality multi-channel extension for stereo players and enhanced multi-channel players is obtained.

Description

Compatible πralti- channel coding/decoding
Field of the invention
The present invention relates to an apparatus and a method for processing a multi-channel audio signal and, in particular, to an apparatus and a method for processing a multi-channel audio signal in a stereo-compatible manner.
Background of the Invention and Prior Art
In recent times, the multi-channel audio reproduction tech- nique is becoming more and more important. This may be due to the fact that audio compression/encoding techniques such as the well-known mp3 technique have made it possible to distribute audio records via the Internet or other transmission channels having a limited bandwidth. The mp3 coding technique has become so famous because of the fact that it allows distribution of all the records in a stereo format, i.e., a digital representation of the audio record including a first or left stereo channel and a second or right stereo channel.
Nevertheless, there are basic shortcomings of conventional two-channel sound systems. Therefore, the surround technique has been developed. A recommended multi-channel- surround representation includes, in addition to the two stereo channels L and R, an additional center channel C and two surround channels Ls, Rs. This reference sound format is also referred to as three/two-stereo, which means three front channels and two surround channels. Generally, five transmission channels are required. In a playback environment, at least five speakers at the respective five different places are needed to get an optimum sweet spot in a certain distance from the five well-placed loudspeakers.
Several techniques are known in the art for reducing the amount of data required for transmission of a multi-channel audio signal. Such techniques are called joint stereo techniques. To this end, reference is made to Fig. 10, which shows a joint stereo device 60. This device can be a device implementing e.g. intensity stereo (IS) or binaural cue coding (BCC) . Such a device generally receives - as an input - at least two channels (CHI, CH2, ... CHn) , and outputs a single carrier channel and parametric data. The paramet- ric data are defined such that, in a decoder, an approximation of an original channel (CHI, CH2, ... CHn) can be calculated.
Normally, the carrier channel will include subband samples, spectral coefficients, time domain samples etc, which provide a comparatively fine representation of the underlying signal, while the parametric data do not include such samples of spectral coefficients but include control parameters for controlling a certain reconstruction algorithm such as weighting by multiplication, time shifting, frequency shifting, ... The parametric data, therefore, include only a comparatively coarse representation of the signal or the associated channel. Stated in numbers, the amount of data required by a carrier channel will be in the range of 60 - 70 kbit/s, while the amount of data required by parametric side information for one channel will be in the range of 1,5 - 2,5 kbit/s. An example for parametric data are the well-known scale factors, intensity stereo information or binaural cue parameters as will be described below.
Intensity stereo coding is described in AES preprint 3799, "Intensity Stereo Coding", J. Herre, K. H. Brandenburg, D. Lederer, February 1994, Amsterdam. Generally, the concept of intensity stereo is based on a main axis transform to be applied to the data of both stereophonic audio channels. If most of the data points are concentrated around the first principle axis, a coding gain can be achieved by rotating both signals by a certain angle prior to coding. This is, however, not always true for real stereophonic production techniques. Therefore, this technique is modified by excluding the second orthogonal component from transmission in the bit stream. Thus, the reconstructed signals for the left and right channels consist of differently weighted or scaled versions of the same transmitted signal. Nevertheless, the reconstructed signals differ in their amplitude but are identical regarding their phase information. The energy-time envelopes of both original audio channels, however, are preserved by means of the selective scaling operation, which typically operates in a frequency selective manner. This conforms to the human perception of sound at high frequencies, where the dominant spatial cues are de- termined by the energy envelopes.
Additionally, in practically implementations, the transmitted signal, i.e. the carrier channel is generated from the sum signal of the left channel and the right channel in- stead of rotating both components. Furthermore, this processing, i.e., generating intensity stereo parameters for performing the scaling operation, is performed frequency selective, i.e., independently for each scale factor band, i.e., encoder frequency partition. Preferably, both channels are combined to form a combined or "carrier" channel, and, in addition to the combined channel, the intensity stereo information is determined which depend on the energy of the first channel, the energy of the second channel or the energy of the combined or channel.
The BCC technique is described in AES convention paper 5574, "Binaural cue coding applied to stereo and multi- channel audio compression", C. Faller, F. Baumgarte, May 2002, Munich. In BCC encoding, a number of audio input channels are converted to a spectral representation using a DFT based transform with overlapping windows. The resulting uniform spectrum is divided into non-overlapping partitions each having an index. Each partition has a bandwidth proportional to the equivalent rectangular bandwidth (ERB) . The inter-channel level differences (ICLD) and the inter- channel time differences (ICTD) are estimated for each partition for each frame k. The ICLD and ICTD are quantized and coded resulting in a BCC bit stream. The inter-channel level differences and inter-channel time differences are given for each channel relative to a reference channel. Then, the parameters are calculated in accordance with prescribed formulae, which depend on the certain partitions of the signal to be processed.
At a decoder-side, the decoder receives a mono signal and the BCC bit stream. The mono signal is transformed into the frequency domain and input into a spatial synthesis block, which also receives decoded ICLD and ICTD values. In the spatial synthesis block, the BCC parameters (ICLD and ICTD) values are used to perform a weighting operation of the mono signal in order to synthesize the multi-channel sig- nals, which, after a frequency/time conversion, represent a reconstruction of the original multi-channel audio signal.
In case of BCC, the joint stereo module 60 is operative to output the channel side information such that the parametric channel data are quantized and encoded ICLD or ICTD parameters, wherein one of the original channels is used as the reference channel for coding the channel side information.
Normally, the carrier channel is formed of the sum of the participating original channels.
Naturally, the above techniques only provide a mono repre- sentation for a decoder, which can only process the carrier channel, but is not able to process the parametric data for generating one or more approximations of more than one input channel.
To transmit the five channels in a compatible way, i.e., in a bitstream format, which is also understandable for a normal stereo decoder, the so-called matrixing technique has been used as described in "MUSICAM surround: a universal multi-channel coding system compatible with ISO 11172-3", G. Theile and G. Stoll, AES preprint 3403, October 1992, San Francisco. The five input channels L, R, C, Ls, and Rs are fed into a matrixing device performing a matrixing operation to calculate the basic or compatible stereo channels Lo, Ro, from the five input channels. In particular, these basic stereo channels Lo/Ro are calculated as set out below: Lo = L + xC + yLs Ro = R + xC + yRs
x and y are constants. The other three channels C, Ls, Rs are transmitted as they are in an extension layer, in addition to a basic stereo layer, which includes an encoded version of the basic stereo signals Lo/Ro. With respect to the bitstrea , this Lo/Ro basic stereo layer includes a header, information such as scale factors and subband sam- pies. The multi-channel extension layer, i.e., the central channel and the two surround channels are included in the multi-channel extension field, which is also called ancillary data field.
At a decoder-side, an inverse matrixing operation is performed in order to form reconstructions of the left and right channels in the five-channel representation using the basic stereo channels Lo, Ro and the three additional channels. Additionally, the three additional channels are de- coded from the ancillary information in order to obtain a decoded five-channel or surround representation of the original multi-channel audio signal.
Another approach for multi-channel encoding is described in the publication "Improved MPEG-2 audio multi-channel encoding", B. Grill, J. Herre, K. H. Brandenburg, E. Eberlein, J. Roller, J. Mueller, AES preprint 3865, February 1994, Amsterdam, in which, in order to obtain backward compatibility, backward compatible modes are considered. To this end, a compatibility matrix is used to obtain two so-called downmix channels Lc, Re from the original five input channels. Furthermore, it is possible to dynamically select the three auxiliary channels transmitted as ancillary data. In order to exploit stereo irrelevancy, a joint stereo technique is applied to groups of channels, e. g. the three front channels, i.e., for the left channel, the right chan- nel and the center channel. To this end, these three channels are combined to obtain a combined channel. This combined channel is quantized and packed into the bitstream. Then, this combined channel together with the corresponding joint stereo information is input into a joint stereo de- coding module to obtain joint stereo decoded channels, i.e., a joint stereo decoded left channel, a joint stereo decoded right channel and a joint stereo decoded center channel. These joint stereo decoded channels are, together with the left surround channel and the right surround chan- nel input into a compatibility matrix block to form the first and the second downmix channels Lc, Re. Then, quantized versions of both downmix channels and a quantized version of the combined channel are packed into the bit- stream together with joint stereo coding parameters.
Using intensity stereo coding, therefore, a group of independent original channel signals is transmitted within a single portion of "carrier" data. The decoder then reconstructs the involved signals as identical data, which are rescaled according to their original energy-time envelopes. Consequently, a linear combination of the transmitted channels will lead to results, which are quite different from the original downmix. This applies to any kind of joint stereo coding based on the intensity stereo concept. For a coding system providing compatible downmix channels, there is a direct consequence: The reconstruction by dematrixing, as described in the previous publication, suffers from artifacts caused by the imperfect reconstruction. Using a so- called joint stereo predistortion scheme, in which a joint stereo coding of the left, the right and the center channels is performed before matrixing in the encoder, alleviates this problem. In this way, the dematrixing scheme for reconstruction introduces fewer artifacts, since, on the encoder-side, the joint stereo decoded signals have been used for generating the downmix channels. Thus, the imperfect reconstruction process is shifted into the compatible downmix channels Lc and Re, where it is much more likely to be masked by the audio signal itself.
Although such a system has resulted in fewer artifacts because of dematrixing on the decoder-side, it nevertheless has some drawbacks. A drawback is that the stereo- compatible downmix channels Lc and Re are derived not from the original channels but from intensity stereo coded/decoded versions of the original channels. Therefore, data losses because of the intensity stereo coding system are included in the compatible downmix channels. Astereo- only decoder, which only decodes the compatible channels rather than the enhancement intensity stereo encoded channels, therefore, provides an output signal, which is affected by intensity stereo induced data losses.
Additionally, a full additional channel has to be transmitted besides the two downmix channels. This channel is the combined channel, which is formed by means of joint stereo coding of the left channel, the right channel and the center channel. Additionally, the intensity stereo information to reconstruct the original channels L, R, C from the combined channel also has to be transmitted to the decoder. At the decoder, an inverse matrixing, i.e., a dematrixing operation is performed to derive the surround channels from the two downmix channels. Additionally, the original left, right and center channels are approximated by joint stereo decoding using the transmitted combined channel and the transmitted joint stereo parameters. It is to be noted that the original left, right and center channels are derived by joint stereo decoding of the combined channel.
Summary of the Invention
It is the object of the present invention to provide a concept for a bit-efficient and artifact-reduced processing or inverse processing of a multi-channel audio signal.
In accordance with a first aspect of the present invention, this object is achieved by an apparatus for processing a multi-channel audio signal, the multi-channel audio signal having at least three original channels, comprising: means for providing a first downmix channel and a second downmix channel, the first and the second downmix channels being derived from the original channels; means for calculating channel side information for a selected original channel of the original signals, the means for calculating being operative to calculate the channel side information such that a downmix channel or a combined downmix channel including the first and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel; and means for generating output data, the output data including the channel side information, the first downmix channel or a signal derived from the first downmix channel and the second downmix channel or a signal derived from the second downmix channel. In accordance with a second aspect of the present invention, this object is achieved by a method of processing a multi-channel audio signal, the multi-channel audio signal having at least three original channels, comprising: providing a first downmix channel and a second downmix channel, the first and the second downmix channels being derived from the original channels; calculating channel side information for a selected original channel of the original signals such that a downmix channel or a combined downmix channel including the first and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel; and generating output data, the output data including the chan- nel side information, the first downmix channel or a signal derived from the first downmix channel and the second down- mix channel or a signal derived from the second downmix channel.
In accordance with a third aspect of the present invention, this object is achieved by an apparatus for inverse processing of input data, the input data including channel side information, a first downmix channel or a signal derived from the first downmix channel and a second downmix channel or a signal derived from the second downmix channel, wherein the first downmix channel and the second downmix channel are derived from at least three original channels of a multi-channel audio signal, and wherein the channel side information are calculated such that a downmix channel or a combined downmix channel including the first downmix channel and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel, the apparatus comprising: an input data reader for reading the input data to obtain the first downmix channel or a signal derived from the first downmix channel and the second downmix channel or a signal derived from the second downmix channel and the channel side information; and a channel reconstructor for reconstructing the approximation of the selected original channel using the channel side information and the downmix channel or the combined downmix channel to obtain the approximation of the selected original channel.
In accordance with a fourth aspect of the present invention, this object is achieved by a method of inverse processing of input data, the input data including channel side information, a first downmix channel or a signal derived from the first downmix channel and a second downmix channel or a signal derived from the second downmix channel, wherein the first downmix channel and the second downmix channel are derived from at least three original channels of a multi-channel audio signal, and wherein the channel side information are calculated such that a downmix channel or a combined downmix channel including the first downmix channel and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel, the method comprising: reading the input data to obtain the first downmix channel or a signal derived from the first downmix channel and the second downmix channel or a signal derived from the second downmix channel and the channel side information; and reconstructing the approximation of the selected original channel using the channel side information and the downmix channel or the combined downmix channel to obtain the approximation of the selected original channel. In accordance with a fifth aspect and a sixth aspect of the present invention, this object is achieved by a computer program including the method of processing or the method of inverse processing.
The present invention is based on the finding that an efficient and artifact-reduced encoding of multi-channel audio signal is obtained, when two downmix channels preferably representing the left and right stereo channels, are packed into output data.
Inventively, parametric channel side information for one or more of the original channels are derived such that they relate to one of the downmix channels rather than, as in the prior art, to an additional "combined" joint stereo channel. This means that the parametric channel side information are calculated such that, on a decoder side, a channel reconstructor uses the channel side information and one of the downmix channels or a combination of the downmix channels to reconstruct an approximation of the original audio channel, to which the channel side information is assigned.
The inventive concept is advantageous in that it provides a bit-efficient multi-channel extension such that a multichannel audio signal can be played at a decoder.
Additionally, the inventive concept is backward compatible, since a lower scale decoder, which is only adapted for two- channel processing, can simply ignore the extension information, i.e., the channel side information. The lower scale decoder can only play the two downmix channels to obtain a stereo representation of the original multi-channel audio signal. A higher scale decoder, however, which is enabled for multi-channel operation, can use the transmitted channel side information to reconstruct approximations of the original channels.
The present invention is advantageous in that it is bit- efficient, since, in contrast to the prior art, no additional carrier channel beyond the first and second downmix channels Lc, Re is required. Instead, the channel side in- formation are related to one or both downmix channels. This means that the downmix channels themselves serve as a carrier channel, to which the channel side information are combined to reconstruct an original audio channel. This means that the channel side information are preferably pa- rarαetric side information, i.e., information which do not include any subband samples or spectral coefficients. Instead, the parametric side information are information used for weighting (in time and/or frequency) the respective downmix channel or the combination of the respective down- mix channels to obtain a reconstructed version of a selected original channel.
In a preferred embodiment of the present invention, a backward compatible coding of a multi-channel signal based on a compatible stereo signal is obtained. Preferably, the compatible stereo signal (downmix signal) is generated using matrixing of the original channels of multi-channel audio signal.
Inventively, channel side information for a selected original channel is obtained based on joint stereo techniques such as intensity stereo coding or binaural cue coding. Thus, at the decoder side, no dematrixing operation has to be performed. The problems associated with dematrixing, i.e., certain artifacts related to an undesired distribution of quantization noise in dematrixing operations, are avoided. This is due to the fact that the decoder uses a channel reconstructor, which reconstructs an original signal, by using one of the downmix channels or a combination of the downmix channels and the transmitted channel side information.
Preferably, the inventive concept is applied to a multichannel audio signal having five channels. These five channels are a left channel L, a right channel R, a center channel C, a left surround channel Ls, and a right surround channel Rs . Preferably, downmix channels are stereo com- patible downmix channels Ls and Rs, which provide a stereo representation of the original multi-channel audio signal.
In accordance with the preferred embodiment of the present invention, for each original channel, channel side informa- tion are calculated at an encoder side packed into output data. Channel side information for the original left channel are derived using the left downmix channel. Channel side information for the original left surround channel are derived using the left downmix channel. Channel side infor- ation for the original right channel are derived from the right downmix channel. Channel side information for the original right surround channel are derived from the right downmix channel.
In accordance with the preferred embodiment of the present invention, channel information for the original center channel are derived using the first downmix channel as well as the second downmix channel, i.e., using a combination of the two downmix channels. Preferably, this combination is a summation.
Thus, the groupings, i.e., the relation between the channel side information and the carrier signal, i.e., the used downmix channel for providing channel side information for a selected original channel are such that, for optimum quality, a certain downmix channel is selected, which contains the highest possible relative amount of the respec- tive original multi-channel signal which is represented by means of channel side information. As such a joint stereo carrier signal, the first and the second downmix channels are used. Preferably, also the sum of the first and the second downmix channels can be used. Naturally, the sum of the first and second downmix channels can be used for calculating channel side information for each of the original channels. Preferably, however, the sum of the downmix channels is used for calculating the channel side information of the original center channel in a surround environment, such as five channel surround, seven channel surround, 5.1 surround or 7.1 surround. Using the sum of the first and second downmix channels is especially advantageous, since no additional transmission overhead has to be performed. This is due to the fact that both downmix channels are pre- sent at the decoder such that summing of these downmix channels can easily be performed at the decoder without requiring any additional transmission bits.
Preferably, the channel side information forming the multi- channel extension are input into the output data bit stream in a compatible way such that a lower scale decoder simply ignores the multi-channel extension data and only provides a stereo representation of the multi-channel audio signal. Nevertheless, a higher scale encoder not only uses two downmix channels, but, in addition, employs the channel side information to reconstruct a full multi-channel representation of the original audio signal.
An inventive decoder is operative to firstly decode both downmix channels and to read the channel side information for the selected original channels. Then, the channel side information and the downmix channels are used to recon- struct approximations of the original channels. To this end, preferably no dematrixing operation at all is performed. This means that, in this embodiment, each of the e. g. five original input channels are reconstructed using e. g. five sets of different channel side information. In the decoder, the same grouping as in the encoder is performed for calculating the reconstructed channel approximation. In a five-channel surround environment, this means that, for reconstructing the original left channel, the left downmix channel and the channel side information for the left chan- nel are used. To reconstruct the original right channel, the right downmix channel and the channel side information for the right channel are used. To reconstruct the original left surround channel, the left downmix channel and the channel side information for the left surround channel are used. To reconstruct the original right surround channel, the channel side information for the right surround channel and the right downmix channel are used. To reconstruct the original center channel, a combined channel formed from the first downmix channel and the second downmix channel and the center channel side information are used.
Naturally, it is also possible, to replay the first and second downmix channels as the left and right channels such that only three sets (out of e. g. five) of channel side information parameters have to be transmitted. This is, however, only advisable in situations, where there are less stringent rules with respect to quality. This is due to the fact that, normally, the left downmix channel and the right downmix channel are different from the original left channel or the original right channel. Only in situations, where one can not afford to transmit channel side information for each of the original channels, such processing is advantageous.
Brief Description of the Drawings
Preferred embodiments of the present invention are subsequently discussed with reference to the attached figures, in which:
Fig. 1 is a block diagram of a preferred embodiment of the inventive encoder;
Fig. 2 is a block diagram of a preferred embodiment of the inventive decoder;
Fig. 3A is a block diagram for a preferred implementation of the means for calculating to obtain frequency selective channel side information;
Fig. 3B is a preferred embodiment of a calculator imple- menting joint stereo processing such as intensity coding or binaural cue coding; Fig, 4 illustrates another preferred embodiment of the means for calculating channel side information, in which the channel side information are gain factors;
Fig. 5 illustrates a preferred embodiment of an implementation of the decoder, when the encoder is implemented as in Fig. 4;
Fig. 6 illustrates a preferred implementation of the means for providing the downmix channels;
Fig. 7 illustrates groupings of original and downmix channels for calculating the channel side infor- ation for the respective original channels;
Fig. 8 illustrates another preferred embodiment of an inventive encoder;
Fig. 9 illustrates another implementation of an inventive decoder; and
Fig. 10 illustrates a prior art joint stereo encoder.
Detailed Description of Preferred Embodiments
Fig. 1 shows an apparatus for processing a multi-channel audio signal 10 having at least three original channels such as R, L and C. Preferably, the original audio signal has more than three channels, such as five channels in the surround environment, which is illustrated in Fig. 1. The five channels are the left channel L, the right channel R, the center channel C, the left surround channel Ls and the right surround channel Rs . The inventive apparatus includes means 12 for providing a first downmix channel Lc and a second downmix channel Re, the first and the second downmix channels being derived from the original channels. For deriving the downmix channels from the original channels, there exist several possibilities. One possibility is to derive the downmix channels Lc and Re by means of matrixing the original channels using a matrixing operation as illus- trated in Fig. 6. This matrixing operation is performed in the time domain.
The matrixing parameters a, b and t are selected such that they are lower than or equal to 1. Preferably, a and b are 0.7 or 0.5. The overall weighting parameter t is preferably chosen such that channel clipping is avoided. . Alternatively, as it is indicated in Fig. 1, the downmix channels l>c and Re can also be externally supplied. This may be done, when the downmix channels Lc and Re are the result of a "hand mixing" operation. In this scenario, a sound engineer mixes the downmix channels by himself rather than by using an automated matrixing operation. The sound engineer performs creative mixing to get optimized downmix channels Lc and Re which give the best possible stereo rep- resentation of the original multi-channel audio signal.
In case of an external supply of the downmix channels, the means for providing does not perform a matrixing operation but simply forwards the externally supplied downmix chan- nels to a subsequent calculating means 14.
The calculating means 14 is operative to calculate the channel side information such as l±, lsi, ri or si for se- lected original channels such as L, Ls, R or Rs, respectively. In particular, the means 14 for calculating is operative to calculate the channel side information such that a downmix channel, when weighted using the channel side in- formation, results in an approximation of the selected original channel.
Alternatively or additionally, the means for calculating channel side information is further operative to calculate the channel side information for a selected original channel such that a combined downmix channel including a combination of the first and second downmix channels, when weighted using the calculated channel side information results in an approximation of the selected original channel. To show this feature in the figure, an adder 14a and a combined channel side information calculator 14b are shown.
It is clear for those skilled in the art that these elements do not have to be implemented as distinct elements. Instead, the whole functionality of the blocks 14, 14a, and 14b can be implemented by means of a certain processor which may be a general purpose processor or any other means for performing the required functionality.
Additionally, it is to be noted here that channel signals being subband samples or frequency domain values are indicated in capital letters. Channel side information are, in contrast to the channels themselves, indicated by small letters. The channel side information cx is, therefore, the channel side information for the original center channel C.
The channel side information as well as the downmix channels Lc and Re or an encoded version Lc' and Re' as pro- duced by an audio encoder 16 are input into an output data formatter 18. Generally, the output data formatter 18 acts as means for generating output data, the output data including the channel side information for at least one original channel, the first downmix channel or a signal derived from the first downmix channel (such as an encoded version thereof) and the second downmix channel or a signal derived from the second downmix channel (such as an encoded version thereof) .
The output data or output bitstream 20 can then be transmitted to a bitstream decoder or can be stored or distributed. Preferably, the output bitstream 20 is a compatible bitstream which can also be read by a lower scale decoder not having a multi-channel extension capability. Such lower scale encoders such as most existing normal state of the art mp3 decoders will simply ignore the multi-channel extension data, i.e., the channel side information. They will only decode the first and second downmix channels to pro- duce a stereo output. Higher scale decoders, such as multichannel enabled decoders will read the channel side information and will then generate an approximation of the original audio channels such that a multi-channel audio impression is obtained.
Fig. 8 shows a preferred embodiment of the present invention in the environment of five channel surround / mp3. Here, it is preferred to write the surround enhancement data into the- ancillary data field in the standardized mp3 bit stream syntax such that an "mp3 surround" bit stream is obtained. Fig. 2 shows an illustration of an inventive decoder acting as an apparatus for inverse processing input data received at an input data port 22. The data received at the input data port 22 is the same data as output at the output data port 20 in Fig. 1. Alternatively, when the data are not transmitted via a wired channel but via a wireless channel, the data received at data input port 22 are data derived from the original data produced by the encoder.
The decoder input data are input into a data stream reader 24 for reading the input data to finally obtain the channel side information 26 and the left downmix channel 28 and the right downmix channel 30. In case the input data includes encoded versions of the downmix channels, which corresponds to the case, in which the audio encoder 16 in Fig. 1 is present, the data stream reader 24 also includes an audio decoder, which is adapted to the audio encoder used for encoding the downmix channels. In this case, the audio decoder, which is part of the data stream reader 24, is op- erative to generate the first downmix channel Lc and the second downmix channel Re, or, stated more exactly, a decoded version of those channels. For ease of description, a distinction between signals and decoded versions thereof is only made where explicitly stated.
The channel side information 26 and the left and right downmix channels 28 and 30 output by the data stream reader 24 are fed into a multi-channel reconstructor 32 for providing a reconstructed version 34 of the original audio signals, which can be played by means of a multi-channel player 36. In case the multi-channel reconstructor is operative in the frequency domain, the multi-channel player 36 will receive frequency domain input data, which have to be in a certain way decoded such as converted into the time domain before playing them. To this end, the multi-channel player 36 may also include decoding facilities.
It is to be noted here that a lower scale decoder will only have the data stream reader 24, which only outputs the left and right downmix channels 28 and 30 to a stereo output 38. An enhanced inventive decoder will, however, extract the channel side information 26 and use these side information and the downmix channels 28 and 30 for reconstructing reconstructed versions 34 of the original channels using the multi-channel reconstructor 32.
Fig. 3A shows an embodiment of the inventive calculator 14 for calculating the channel side information, which an audio encoder on the one hand and the channel side information calculator on the other hand operate on the same spectral representation of multi-channel signal. Fig. 1, however, shows the other alternative, in which the audio en- coder on the one hand and the channel side information calculator on the other hand operate on different spectral representations of the multi-channel signal. When computing resources are not as important as audio quality, the Fig. 1 alternative is preferred, since filterbanks individually optimized for audio encoding and side information calculation can be used. When, however, computing resources are an issue, the Fig. 3A alternative is preferred, since this alternative requires less computing power because of a shared utilization of elements.
The device shown in Fig. 3A is operative for receiving two channels A, B. The device shown in Fig. 3A is operative to calculate a side information for channel B such that using this channel side information for the selected original channel B, a reconstructed version of channel B can be calculated from the channel signal A. Additionally, the device shown in Fig. 3A is operative to form frequency domain channel side information, such as parameters for weighting (by multiplying or time processing as in BCC coding e. g. ) spectral values or subband samples. To this end, the inventive calculator includes windowing and time/frequency conversion means 140a to obtain a frequency representation of channel A at an output 140b or a frequency domain representation of channel B at an output 140c.
In the preferred embodiment, the side information determination (by means of the side information determination means 140f) is performed using quantized spectral values. Then, a quantizer 140d is also present which preferably is controlled using a psychoacoustic model having a psycho- acoustic model control input 14Oe. Nevertheless, a quantizer is not required, when the side information determina- tion means 140c uses a non-quantized representation of the channel A for determining the channel side information for channel B.
In case the channel side information for channel B are cal- culated by means of a frequency domain representation of the channel A and the frequency domain representation of the channel B, the windowing and time/frequency conversion means 140a can be the same as used in a filterbank-based audio encoder. In this case, when AAC (ISO/IEC 13818-3) is considered, means 140a is implemented as an MDCT filter bank (MDCT = modified discrete cosine transform) with 50% overlap-and-add functionality. In such a case, the quantizer 140d is an iterative quantizer such as used when mp3 or AAC encoded audio signals are generated. The frequency domain representation of channel A, which is preferably already quantized can then be directly used for entropy encoding using an entropy encoder 14Og, which may be a Huffman based encoder or an entropy encoder implementing arithmetic encoding.
When compared to Fig. 1, the output of the device in Fig. 3A is the side information such as lj. for one original channel (corresponding to the side information for B at the output of device 140f) . The entropy encoded bitstream for channel A corresponds to e. g. the encoded left downmix channel Lc' at the output of block 16 in Fig. 1. From Fig. 3A it becomes clear that element 14 (Fig. 1), i.e., the calculator for calculating the channel side information and the audio encoder 16 (Fig. 1) can be implemented as separate means or can be implemented as a shared version such that both devices share several elements such as the MDCT filter bank 140a, the quantizer 140e and the entropy encoder 140g. Naturally, in case one needs a different transform etc. for determining the channel side information, then the encoder 16 and the calculator 14 (Fig. 1) will be implemented in different devices such that both elements do not share the filter bank etc.
Generally, the actual deter inator for calculating the side information (or generally stated the calculator 14) may be implemented as a joint stereo module as shown in Fig.3B, which operates in accordance with any of the joint stereo techniques such as intensity stereo coding or binaural cue coding. In contrast to such prior art intensity stereo encoders, the inventive determination means 140f does not have to calculate the combined channel. The "combined channel" or carrier channel, as one can say, already exists and is the left compatible downmix channel Lc or the right compatible downmix channel Re or a combined version of these downmix channels such as Lc + Re. Therefore, the inventive device 14Of only has to calculate the scaling information for scaling the respective downmix channel such that the en- ergy/time envelope of the respective selected original channel is obtained, when the downmix channel is weighted using the scaling information or, as one can say, the intensity directional information.
Therefore, the joint stereo module 140f in Fig 3B is illustrated such that it receives, as an input, the "combined" channel A, which is the first or second downmix channel or a combination of the downmix channels, and the original selected channel. This module, naturally, outputs the "com- bined" channel A and the joint stereo parameters as channel side information such that, using the combined channel A and the joint stereo parameters, an approximation of the original selected channel B can be calculated.
Alternatively, the joint stereo module 140f can be implemented for performing binaural cue coding.
In the case of BCC, the joint stereo module 140f is operative to output the channel side information such that the channel side information are quantized and encoded ICLD or ICTD parameters, wherein the selected original channel serves as the actual to be processed channel, while the respective downmix channel used for calculating the side in- formation, such as the first, the second or a combination of the first and second downmix channels is used as the reference channel in the sense of the BCC coding/decoding technique.
Referring to Fig. 4, a simple energy-directed implementation of element 140f is given. This device includes a frequency band selector 44 selecting a frequency band from channel A and a corresponding frequency band of channel B. Then, in both frequency bands, an energy is calculated by means of an energy calculator 42 for each branch. The detailed implementation of the energy calculator 42 will depend on whether the output signal from block 40 is a sub- band signal or are frequency coefficients. In other imple- mentations, where scale factors for scale factor bands are calculated, one can already use scale factors of the first and second channel A, B as energy values Ea and EB or at least as estimates of the energy. In a gain factor calculating device 44, a gain factor gB for the selected fre- quency band is determined based on a certain rule such as the gain determining rule illustrated in block 44 in Fig. 4. Here, the gain factor gB can directly be used for weighting time domain samples or frequency coefficients such as will be described later in Fig. 5. To this end, the gain factor gB, which is valid for the selected frequency band is used as the channel side information for channel B as the selected original channel. This selected original channel B will not be transmitted to decoder but will be represented by the parametric channel side information as calculated by the calculator 14 in Fig. 1.
It is to be noted here that it is not necessary to transmit gain values as channel side information. It is also suffi- cient to transmit frequency dependent values related to the absolute energy of the selected original channel. Then, the decoder has to calculate the actual energy of the downmix channel and the gain factor based on the downmix channel energy and the transmitted energy for channel B.
Fig. 5 shows a possible implementation of a decoder set up in connection with a transform-based perceptual audio encoder. Compared to Fig. 2, the functionalities of the en- tropy decoder and inverse quantizer 50 (Fig. 5) will be included in block 24 of Fig. 2. The functionality of the frequency/time converting elements 52a, 52b (Fig. 5) will, however, be implemented in item 36 of Fig. 2. Element 50 in Fig. 5 receives an encoded version of the first or the sec- ond downmix signal Lc' or Re' . At the output of element 50, an at least partly decoded version of the first and the second downmix channel is present which is subsequently called channel A. Channel A is input into a frequency band selector 54 for selecting a certain frequency band from channel A. This selected frequency band is weighted using a multiplier 56. The multiplier 56 receives, for multiplying, a certain gain factor gB, which is assigned to the selected frequency band selected by the frequency band selector 54, which corresponds to the frequency band selector 40 in Fig. 4 at the encoder side. At the input of the frequency time converter 52a, there exists, together with other bands, a frequency domain representation of channel A. At the output of multiplier 56 and, in particular, at the input of frequency/time conversion means 52b there will . be a recon- structed frequency domain representation of channel B. Therefore, at the output of element 52a, there will be a time domain representation for channel A, while, at the output of element 52b, there will be a time domain representation of reconstructed channel B.
It is to be noted here that, depending on the certain im- plementation, the decoded downmix channel Lc or Re is not played back in a multi-channel enhanced decoder. In such a multi-channel enhanced decoder, the decoded downmix channels are only used for reconstructing the original channels. The decoded downmix channels are only replayed in lower scale stereo-only decoders.
To this end, reference is made to Fig. 9, which shows the preferred implementation of the present invention in a sur- round/mp3 environment. An mp3 enhanced surround bitstream is input into a standard mp3 decoder 24, which outputs decoded versions of the original downmix channels. These downmix channels can then be directly replayed by means of a low level decoder. Alternatively, these two channels are input into the advanced joint stereo decoding device 32 which also receives the multi-channel extension data, which are preferably input into the ancillary data field in a mp3 compliant bitstream.
Subsequently, reference is made to Fig. 7 showing the grouping of the selected original channel and the respective downmix channel or combined downmix channel. In this regard, the right column of the table in Fig. 7 corresponds to channel A in Fig. 3A, 3B, 4 and 5, while the column in the middle corresponds to channel B in these figures. In the left column in Fig. 7, the respective channel side information is explicitly stated. In accordance with the Fig. 7 table, the channel side information li for the original left channel L is calculated using the left downmix channel Lc. The left surround channel side information lsi is determined by means of the original selected left surround channel Ls and the left downmix channel Lc is the carrier. The right channel side information i for the original right channel R are determined using the right downmix channel Re. Additionally, the channel side information for the right surround channel Rs are determined using the right downmix channel Re as the carrier. Finally, the channel side information ci for the center channel C are deter- mined using the combined downmix channel, which is obtained by means of a combination of the first and the second down- mix channel, which can be easily calculated in both an encoder and a decoder and which does not require any extra bits for transmission.
Naturally, one could also calculate the channel side information for the left channel e. g. based on a combined down- mix channel or even a downmix channel, which is obtained by a weighted addition of the first and second downmix chan- nels such as 0.7 Lc and 0.3 Re, as long as the weighting parameters are known to a decoder or transmitted accordingly. For most applications, however, it will be preferred to only derive channel side information for the center channel from the combined downmix channel, i.e., from a combination of the first and second downmix channels.
To show the bit saving potential of the present invention, the following typical example is given. In case of a five channel audio signal, a normal encoder needs a bit rate of 64 kbit/s for each channel amounting to an overall bit rate of 320 kbit/s for the five channel signal. The left and right stereo signals require a bit rate of 128 kbit/s. Channels side information for one channel are between 1.5 and 2 kbit/s. Thus, even in a case, in which channel side information for each of the five channels are transmitted, this additional data add up to only 7.5 to 10 kbit/s. Thus, the inventive concept allows transmission of a five channel audio signal using a bit rate of 138 kbit/s (compared to 320 (!) kbit/s) with good quality, since the decoder does not use the problematic dematrixing operation. Probably even more important is the fact that the inventive concept is fully backward compatible, since each of the existing mp3 players is able to replay the first downmix channel and the second downmix channel to produce a conventional stereo output.
Depending on the application environment, the inventive method for processing or inverse processing can be implemented in hardware or in software. The implementation can be a digital storage medium such as a disk or a CD having electronically readable control signals, which can cooperate with a programmable computer system such that the in- ventive method for processing or inverse processing is carried out. Generally stated, the invention therefore, also relates to a computer program product having a program code stored on a machine-readable carrier, the program code being adapted for performing the inventive method, when the computer program product runs on a computer. In other words, the invention, therefore, also relates to a computer program having a program code for performing the method, when the computer program runs on a computer.

Claims

What is claimed is:
1. Apparatus for processing a multi-channel audio signal, the multi-channel audio signal having at least three original channels, comprising: means (12) for providing a first downmix channel and a second downmix channel, the first and the second downmix channels being derived from the original channels; means (14) for calculating channel side information for a selected original channel of the original signals, the means for calculating being operative to calculate the channel side information such that a downmix channel or a combined downmix channel including the first and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel; and means (18) for generating output data, the output data including the channel side information.
2. Apparatus in accordance with claim 1, in which the means (18) for generating is operative to generate the output data such that the output data additionally include the first downmix channel or a signal derived from the first downmix channel and the second downmix channel or a signal derived from the second downmix channel.
3. Apparatus in accordance with claim 1 or 2, in which the means (14) for calculating is operative to determine the channel side information as parametric data not including time domain samples or spectral values.
4. Apparatus in accordance with any one of the claims 1 to 3 claim 1, in which the means (14) for calculating is operative to perform joint stereo coding using a downmix channel as a carrier channel and using, as an input channel, the selected original channel, to generate joint stereo parameters as channel side information for the selected original channel.
5. Apparatus in accordance with claim 3, in which the means (14) for calculating is operative to perform intensity stereo coding or binaural cue coding, such that the channel side information represent an energy distribution or binaural cue parameters for the selected original channel, wherein a downmix channel or a combined downmix channel is usable as a carrier channel.
6. Apparatus in accordance with claim 1 to 5, in which the multi-channel audio signal includes a left channel, a left surround channel, a right channel and a right surround channel, in which the means (12) for providing is operative to provide the first downmix channel as a left downmix channel and to provide the second downmix channel as a right down- mix channel, the left and the right downmix channels being formed such that a result, when played, is a stereo representation of the multi-channel audio signal, and in which the means (14) for calculating is operative to calculate the channel side information for the left channel as the selected original channel using the left downmix channel, to calculate the channel side information for the right channel as the selected original channel using the right downmix channel, to calculate the channel side information for the left surround channel as the selected original channel using the left downmix channel, and to calculate the channel side information for the right surround channel as the selected original channel using the right downmix channel.
7. Apparatus in accordance with claim 1 to 6, in which the original channels include a center channel, which further includes a combiner (14 a) for combining the first downmix channel and the second downmix channel to obtain the combined downmix channel; and wherein the means for calculating the channel side information for the center channel as the selected original channel is operative to calculate (14 b) the channel side information such that the combined downmix channel when weighted using the channel side information results in an approximation of the original center channel.
8. Apparatus in accordance with claim 1 to 7, in which the means (12) for providing is operative to derive the first downmix channel and the second downmix channel from the original channels using a first predetermined linear weighted combination for the first downmix channel and using a second predetermined linear weighted combination for the second downmix channel.
9. Apparatus in accordance with claim 7, in which the first predetermined linear weighted combination is defined as follows:
Lc = f (L + a'Ls + b-C) ; or in which the predetermined second linear weighted combination is defined as follows:
Re = f (R + a-Rs + b-C) , wherein Lc is the first downmix channel, wherein Re is the second downmix channel, wherein t, a and b are weighting factors smaller than 1, wherein L is an original left channel, wherein C is an original center channel, wherein R is an original right channel, wherein Ls is an original left surround channel, and wherein Rs is an original right surround channel.
10. Apparatus in accordance with claim 1 to 9, in which the means (12) for providing is operative to receive exter- nally supplied first and second downmix channels.
11. Apparatus in accordance with claim 1 to 10, in which the first downmix channel and the second downmix channel are composite channels being composite of the original channels in varying degrees, wherein the means for calculating is operative, to use, for calculating the channel side information, the downmix channel among both downmix channels, which is stronger influenced by the selected original channel when compared to the other downmix channel .
12. Apparatus in accordance with claim 1 to 11, in which the means (18) for generating is operative to form the output data such that the output data are in compliance with an output data syntax to be used by a low level decoder for processing the first downmix channel or a signal derived from the first downmix channel or the second downmix chan- nel or a signal derived from the second downmix channel to obtain a decoded stereo representation of the multi-channel audio signal.
13. Apparatus in accordance with claim 12, in which the output data syntax is structured such that same includes a special data field to be ignored by a low level decoder, and in which the means for generating is operative to insert the channel side information into the special data field.
14. Apparatus in accordance with claim 13, in which the syntax is mp3 syntax and the special data field is an ancillary data field.
15. Apparatus in accordance with claim 12 to 14, in which the means (18) for generating is operative to insert the channel side information into the output data such that the channel side information are only used by a high level decoder but are ignored by the low level decoder.
16. Apparatus in accordance with claim 2 to 15, which fur- ther comprises an encoder (16) for encoding the first down- mix channel to obtain the signal derived from the first downmix channel or for encoding the second downmix channel to obtain the signal derived from the second downmix channel.
17. Apparatus in accordance with claim 16, in which the encoder (16) is a perceptual encoder which includes means for converting a signal to be encoded into a spectral representation, means for quantizing the spectral representa- tion using a psychoacoustic model and means for entropy encoding a quantized spectral representation to obtain an entropy encoded quantized spectral representation as the signal derived from the first downmix channel or the signal derived from the second downmix channel .
18. Apparatus in accordance with claim 17, in which the perceptual encoder (16) is an encoder in accordance with MPEG-1/2 layer III (mp3) or MPEG-2/4 advanced audio coding
(AAC) .
19. Apparatus in accordance with claim 1 to 18, in which the means (14) for calculating is operative to calculate downmix energy values for the downmix channel or the combined downmix channel, to calculate an original energy value for the selected original channel, and to calculate a gain factor as the channel side information, the gain factor being derived from the downmix energy value and the original energy value.
20. Apparatus in accordance with claim 1 to 19, in which the means (14) for calculating is operative to calculate frequency dependent channel side information parameters such that for a plurality of frequency bands, a plurality of different channel side information parameters are ob- tained.
21. Method of processing a multi-channel audio signal, the multi-channel audio signal having at least three original channels, comprising: providing (12) a first downmix channel and a second downmix channel, the first and the second downmix channels being derived from the original channels; calculating (14) channel side information for a selected original channel of the original signals such that a downmix channel or a combined downmix channel including the first and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel; and generating (18) output data, the output data including the channel side information.
22. Apparatus for inverse processing of input data, the input data including channel side information, a first downmix channel or a signal derived from the first downmix channel and a second downmix channel or a signal derived from the second downmix channel, wherein the first downmix channel and the second downmix channel are derived from at least three original channels of a multi-channel audio signal, and wherein the channel side information are calcu- lated such that a downmix channel or a combined downmix channel including the first downmix channel and the second downmix channel, when weighted using the channel side information, results in an approximation of ■ the selected original channel, the apparatus comprising: an input data reader (24) for reading the input data to obtain the first downmix channel or a signal derived from the first downmix channel and the second downmix channel or a signal derived from the second downmix channel and the channel side information; and a channel reconstructor (32) for reconstructing the approximation of the selected original channel using the channel side information and the downmix channel or the combined downmix channel to obtain the approximation of the selected original channel.
23. Apparatus in accordance with claim 22, further comprising a perceptual decoder (24) for decoding the signal derived from the first downmix channel to obtain the decoded version of the first downmix channel and for decoding the signal derived from the second downmix channel to obtain a decoded version of the second downmix channel.
24. Apparatus in accordance with claim 22 to 23, further comprising a combiner for combining the first downmix channel and the second downmix channel to obtain the combined downmix channel .
25. Apparatus in accordance with claim 22 to 24, in which the original audio signal includes a left channel, a left surround channel, a right channel, a right surround channel and center channel, wherein the first downmix channel and the second down- mix channel are a left downmix channel and a right downmix channel, respectively, and wherein the input data include channel side information for at least three of the left channel, the left surround channel, the right channel, the right surround chan- nel and the center channel, wherein the channel reconstructor (32) is operative to reconstruct an approximation of the left chan- nel using channel side information for the left channel and the left downmix channel, to reconstruct an approximation for the left surround channel using channel side information for the left surround channel and the left downmix channel, to reconstruct an approximation for the right channel using channel side information for the right channel and the right downmix channel, and to reconstruct an approximation for the right surround channel using channel side information for the right surround channel and the right downmix channel.
26. Apparatus in accordance with claim 22 to 25, in which the channel reconstructor is operative to reconstruct an approximation for the center channel using channel side information for the center channel and the combined downmix channel.
27. Method of inverse processing of input data, the input data including channel side information, a first downmix channel or a signal derived from the first downmix channel and a second downmix channel or a signal derived from the second downmix channel, wherein the first downmix channel and the second downmix channel are derived from at least three original channels of a multi-channel audio signal, and wherein the channel side information are calculated such that a downmix channel or a combined downmix channel including the first downmix channel and the second downmix channel, when weighted using the channel side information, results in an approximation of the selected original channel, the method comprising: reading (24) the input data to obtain the first down- mix channel or a signal derived from the first downmix channel and the second downmix channel or a signal derived from the second downmix channel and the channel side information; and reconstructing (32) the approximation of the selected original channel using the channel side information and the downmix channel or the combined downmix channel to obtain the approximation of the selected original channel.
28. Computer program having a program code for performing a method in accordance with claim 21 or claim 27
PCT/EP2004/010948 2003-10-02 2004-09-30 Compatible multi-channel coding/decoding WO2005036925A2 (en)

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Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007102674A1 (en) * 2006-03-06 2007-09-13 Samsung Electronics Co., Ltd. Method, medium, and system synthesizing a stereo signal
WO2007102675A1 (en) * 2006-03-06 2007-09-13 Samsung Electronics Co., Ltd. Method, medium, and system generating a stereo signal
JP2008517337A (en) * 2004-11-02 2008-05-22 コーディング テクノロジーズ アクチボラゲット A method for improving the performance of prediction-based multi-channel reconstruction
KR100848367B1 (en) * 2004-04-16 2008-07-24 코딩 테크놀러지스 에이비 Apparatus and method for generating a level parameter and apparatus and method for generating a multi-channel representation
JP2008543227A (en) * 2005-06-03 2008-11-27 ドルビー・ラボラトリーズ・ライセンシング・コーポレーション Reconfiguration of channels with side information
JP2008542815A (en) * 2005-05-26 2008-11-27 エルジー エレクトロニクス インコーポレイティド Audio signal decoding method and apparatus
JP2009501957A (en) * 2005-07-19 2009-01-22 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Multi-channel audio signal generation
JP2009506706A (en) * 2005-08-30 2009-02-12 エルジー エレクトロニクス インコーポレイティド Audio signal decoding method and apparatus
JP2009526258A (en) * 2006-02-07 2009-07-16 エルジー エレクトロニクス インコーポレイティド Encoding / decoding apparatus and method
JP2009539283A (en) * 2006-06-02 2009-11-12 ドルビー スウェーデン アクチボラゲット Binaural multichannel decoder in the context of non-energy-saving upmix rules
US8170218B2 (en) 2007-10-04 2012-05-01 Hurtado-Huyssen Antoine-Victor Multi-channel audio treatment system and method
US8885854B2 (en) 2006-08-09 2014-11-11 Samsung Electronics Co., Ltd. Method, medium, and system decoding compressed multi-channel signals into 2-channel binaural signals
TWI462086B (en) * 2005-09-14 2014-11-21 Lg Electronics Inc Method and apparatus for decoding an audio signal
CN104486033A (en) * 2014-12-03 2015-04-01 重庆邮电大学 Downlink multimode channel coding system and method based on C-RAN platform
US9747905B2 (en) 2005-09-14 2017-08-29 Lg Electronics Inc. Method and apparatus for decoding an audio signal
US9934789B2 (en) 2006-01-11 2018-04-03 Samsung Electronics Co., Ltd. Method, medium, and apparatus with scalable channel decoding

Families Citing this family (139)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE0202159D0 (en) 2001-07-10 2002-07-09 Coding Technologies Sweden Ab Efficientand scalable parametric stereo coding for low bitrate applications
US8605911B2 (en) 2001-07-10 2013-12-10 Dolby International Ab Efficient and scalable parametric stereo coding for low bitrate audio coding applications
EP1423847B1 (en) 2001-11-29 2005-02-02 Coding Technologies AB Reconstruction of high frequency components
US7240001B2 (en) * 2001-12-14 2007-07-03 Microsoft Corporation Quality improvement techniques in an audio encoder
SE0202770D0 (en) 2002-09-18 2002-09-18 Coding Technologies Sweden Ab Method of reduction of aliasing is introduced by spectral envelope adjustment in real-valued filterbanks
KR20050116828A (en) * 2003-03-24 2005-12-13 코닌클리케 필립스 일렉트로닉스 엔.브이. Coding of main and side signal representing a multichannel signal
US7394903B2 (en) * 2004-01-20 2008-07-01 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Apparatus and method for constructing a multi-channel output signal or for generating a downmix signal
US7460990B2 (en) * 2004-01-23 2008-12-02 Microsoft Corporation Efficient coding of digital media spectral data using wide-sense perceptual similarity
KR20070001139A (en) * 2004-02-17 2007-01-03 코닌클리케 필립스 일렉트로닉스 엔.브이. An audio distribution system, an audio encoder, an audio decoder and methods of operation therefore
DE102004009628A1 (en) * 2004-02-27 2005-10-06 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Apparatus and method for writing an audio CD and an audio CD
CA2992097C (en) 2004-03-01 2018-09-11 Dolby Laboratories Licensing Corporation Reconstructing audio signals with multiple decorrelation techniques and differentially coded parameters
US20090299756A1 (en) * 2004-03-01 2009-12-03 Dolby Laboratories Licensing Corporation Ratio of speech to non-speech audio such as for elderly or hearing-impaired listeners
US7813513B2 (en) * 2004-04-05 2010-10-12 Koninklijke Philips Electronics N.V. Multi-channel encoder
DE602005006777D1 (en) * 2004-04-05 2008-06-26 Koninkl Philips Electronics Nv MULTI-CHANNEL CODER
KR101183862B1 (en) * 2004-04-05 2012-09-20 코닌클리케 필립스 일렉트로닉스 엔.브이. Method and device for processing a stereo signal, encoder apparatus, decoder apparatus and audio system
EP1914723B1 (en) * 2004-05-19 2010-07-07 Panasonic Corporation Audio signal encoder and audio signal decoder
US8843378B2 (en) * 2004-06-30 2014-09-23 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Multi-channel synthesizer and method for generating a multi-channel output signal
CN1922655A (en) * 2004-07-06 2007-02-28 松下电器产业株式会社 Audio signal encoding device, audio signal decoding device, method thereof and program
US7751804B2 (en) * 2004-07-23 2010-07-06 Wideorbit, Inc. Dynamic creation, selection, and scheduling of radio frequency communications
TWI393120B (en) * 2004-08-25 2013-04-11 Dolby Lab Licensing Corp Method and syatem for audio signal encoding and decoding, audio signal encoder, audio signal decoder, computer-accessible medium carrying bitstream and computer program stored on computer-readable medium
JP4555299B2 (en) * 2004-09-28 2010-09-29 パナソニック株式会社 Scalable encoding apparatus and scalable encoding method
EP1710799B1 (en) * 2005-02-01 2012-06-20 Panasonic Corporation Reproduction apparatus
EP1691348A1 (en) * 2005-02-14 2006-08-16 Ecole Polytechnique Federale De Lausanne Parametric joint-coding of audio sources
MX2007011915A (en) * 2005-03-30 2007-11-22 Koninkl Philips Electronics Nv Multi-channel audio coding.
MX2007011995A (en) * 2005-03-30 2007-12-07 Koninkl Philips Electronics Nv Audio encoding and decoding.
US7961890B2 (en) * 2005-04-15 2011-06-14 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung, E.V. Multi-channel hierarchical audio coding with compact side information
DE602006011600D1 (en) * 2005-04-28 2010-02-25 Panasonic Corp AUDIOCODING DEVICE AND AUDIOCODING METHOD
WO2006126843A2 (en) * 2005-05-26 2006-11-30 Lg Electronics Inc. Method and apparatus for decoding audio signal
US8170883B2 (en) * 2005-05-26 2012-05-01 Lg Electronics Inc. Method and apparatus for embedding spatial information and reproducing embedded signal for an audio signal
US8494667B2 (en) * 2005-06-30 2013-07-23 Lg Electronics Inc. Apparatus for encoding and decoding audio signal and method thereof
CA2613731C (en) * 2005-06-30 2012-09-18 Lg Electronics Inc. Apparatus for encoding and decoding audio signal and method thereof
EP1908057B1 (en) * 2005-06-30 2012-06-20 LG Electronics Inc. Method and apparatus for decoding an audio signal
US8626503B2 (en) * 2005-07-14 2014-01-07 Erik Gosuinus Petrus Schuijers Audio encoding and decoding
ATE433182T1 (en) * 2005-07-14 2009-06-15 Koninkl Philips Electronics Nv AUDIO CODING AND AUDIO DECODING
US7562021B2 (en) * 2005-07-15 2009-07-14 Microsoft Corporation Modification of codewords in dictionary used for efficient coding of digital media spectral data
US7630882B2 (en) * 2005-07-15 2009-12-08 Microsoft Corporation Frequency segmentation to obtain bands for efficient coding of digital media
JP4568363B2 (en) * 2005-08-30 2010-10-27 エルジー エレクトロニクス インコーポレイティド Audio signal decoding method and apparatus
ATE455348T1 (en) * 2005-08-30 2010-01-15 Lg Electronics Inc DEVICE AND METHOD FOR DECODING AN AUDIO SIGNAL
US7788107B2 (en) * 2005-08-30 2010-08-31 Lg Electronics Inc. Method for decoding an audio signal
EP1921606B1 (en) * 2005-09-02 2011-10-19 Panasonic Corporation Energy shaping device and energy shaping method
US20080221907A1 (en) * 2005-09-14 2008-09-11 Lg Electronics, Inc. Method and Apparatus for Decoding an Audio Signal
JP2009518659A (en) * 2005-09-27 2009-05-07 エルジー エレクトロニクス インコーポレイティド Multi-channel audio signal encoding / decoding method and apparatus
JP5478826B2 (en) * 2005-10-03 2014-04-23 シャープ株式会社 Display device
CN101283249B (en) * 2005-10-05 2013-12-04 Lg电子株式会社 Method and apparatus for signal processing and encoding and decoding method, and apparatus thereof
US7696907B2 (en) 2005-10-05 2010-04-13 Lg Electronics Inc. Method and apparatus for signal processing and encoding and decoding method, and apparatus therefor
US7672379B2 (en) * 2005-10-05 2010-03-02 Lg Electronics Inc. Audio signal processing, encoding, and decoding
US7751485B2 (en) * 2005-10-05 2010-07-06 Lg Electronics Inc. Signal processing using pilot based coding
KR100878833B1 (en) * 2005-10-05 2009-01-14 엘지전자 주식회사 Method and apparatus for signal processing and encoding and decoding method, and apparatus therefor
US7646319B2 (en) * 2005-10-05 2010-01-12 Lg Electronics Inc. Method and apparatus for signal processing and encoding and decoding method, and apparatus therefor
US7653533B2 (en) * 2005-10-24 2010-01-26 Lg Electronics Inc. Removing time delays in signal paths
KR100644715B1 (en) * 2005-12-19 2006-11-10 삼성전자주식회사 Method and apparatus for active audio matrix decoding
US8111830B2 (en) * 2005-12-19 2012-02-07 Samsung Electronics Co., Ltd. Method and apparatus to provide active audio matrix decoding based on the positions of speakers and a listener
WO2007080211A1 (en) * 2006-01-09 2007-07-19 Nokia Corporation Decoding of binaural audio signals
KR101218776B1 (en) 2006-01-11 2013-01-18 삼성전자주식회사 Method of generating multi-channel signal from down-mixed signal and computer-readable medium
US7752053B2 (en) 2006-01-13 2010-07-06 Lg Electronics Inc. Audio signal processing using pilot based coding
US8411869B2 (en) * 2006-01-19 2013-04-02 Lg Electronics Inc. Method and apparatus for processing a media signal
EP1974344A4 (en) * 2006-01-19 2011-06-08 Lg Electronics Inc Method and apparatus for decoding a signal
US20090177479A1 (en) * 2006-02-09 2009-07-09 Lg Electronics Inc. Method for Encoding and Decoding Object-Based Audio Signal and Apparatus Thereof
DE602007004451D1 (en) 2006-02-21 2010-03-11 Koninkl Philips Electronics Nv AUDIO CODING AND AUDIO CODING
KR100904437B1 (en) * 2006-02-23 2009-06-24 엘지전자 주식회사 Method and apparatus for processing an audio signal
US8626515B2 (en) * 2006-03-30 2014-01-07 Lg Electronics Inc. Apparatus for processing media signal and method thereof
CN101361122B (en) * 2006-04-03 2012-12-19 Lg电子株式会社 Method and apparatus for processing a media signal
ES2380059T3 (en) * 2006-07-07 2012-05-08 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Apparatus and method for combining multiple audio sources encoded parametrically
KR101438387B1 (en) 2006-07-12 2014-09-05 삼성전자주식회사 Method and apparatus for encoding and decoding extension data for surround
US7907579B2 (en) * 2006-08-15 2011-03-15 Cisco Technology, Inc. WiFi geolocation from carrier-managed system geolocation of a dual mode device
US20080235006A1 (en) * 2006-08-18 2008-09-25 Lg Electronics, Inc. Method and Apparatus for Decoding an Audio Signal
US9319741B2 (en) 2006-09-07 2016-04-19 Rateze Remote Mgmt Llc Finding devices in an entertainment system
US8607281B2 (en) 2006-09-07 2013-12-10 Porto Vinci Ltd. Limited Liability Company Control of data presentation in multiple zones using a wireless home entertainment hub
US9386269B2 (en) 2006-09-07 2016-07-05 Rateze Remote Mgmt Llc Presentation of data on multiple display devices using a wireless hub
US9233301B2 (en) 2006-09-07 2016-01-12 Rateze Remote Mgmt Llc Control of data presentation from multiple sources using a wireless home entertainment hub
US20080061578A1 (en) * 2006-09-07 2008-03-13 Technology, Patents & Licensing, Inc. Data presentation in multiple zones using a wireless home entertainment hub
US8966545B2 (en) 2006-09-07 2015-02-24 Porto Vinci Ltd. Limited Liability Company Connecting a legacy device into a home entertainment system using a wireless home entertainment hub
US8935733B2 (en) * 2006-09-07 2015-01-13 Porto Vinci Ltd. Limited Liability Company Data presentation using a wireless home entertainment hub
US8005236B2 (en) * 2006-09-07 2011-08-23 Porto Vinci Ltd. Limited Liability Company Control of data presentation using a wireless home entertainment hub
JP5337941B2 (en) * 2006-10-16 2013-11-06 フラウンホッファー−ゲゼルシャフト ツァ フェルダールング デァ アンゲヴァンテン フォアシュンク エー．ファオ Apparatus and method for multi-channel parameter conversion
SG175632A1 (en) * 2006-10-16 2011-11-28 Dolby Sweden Ab Enhanced coding and parameter representation of multichannel downmixed object coding
KR100847453B1 (en) * 2006-11-20 2008-07-21 주식회사 대우일렉트로닉스 Adaptive crosstalk cancellation method for 3d audio
US8265941B2 (en) * 2006-12-07 2012-09-11 Lg Electronics Inc. Method and an apparatus for decoding an audio signal
CN101578656A (en) * 2007-01-05 2009-11-11 Lg电子株式会社 A method and an apparatus for processing an audio signal
JP5291096B2 (en) * 2007-06-08 2013-09-18 エルジー エレクトロニクス インコーポレイティド Audio signal processing method and apparatus
US7761290B2 (en) 2007-06-15 2010-07-20 Microsoft Corporation Flexible frequency and time partitioning in perceptual transform coding of audio
US8046214B2 (en) 2007-06-22 2011-10-25 Microsoft Corporation Low complexity decoder for complex transform coding of multi-channel sound
US7885819B2 (en) * 2007-06-29 2011-02-08 Microsoft Corporation Bitstream syntax for multi-process audio decoding
KR101464977B1 (en) * 2007-10-01 2014-11-25 삼성전자주식회사 Method of managing a memory and Method and apparatus of decoding multi channel data
CN101578655B (en) * 2007-10-16 2013-06-05 松下电器产业株式会社 Stream generating device, decoding device, and method
US8249883B2 (en) * 2007-10-26 2012-08-21 Microsoft Corporation Channel extension coding for multi-channel source
KR101438389B1 (en) * 2007-11-15 2014-09-05 삼성전자주식회사 Method and apparatus for audio matrix decoding
WO2009066959A1 (en) 2007-11-21 2009-05-28 Lg Electronics Inc. A method and an apparatus for processing a signal
WO2009075510A1 (en) * 2007-12-09 2009-06-18 Lg Electronics Inc. A method and an apparatus for processing a signal
TWI424755B (en) * 2008-01-11 2014-01-21 Dolby Lab Licensing Corp Matrix decoder
KR100998913B1 (en) * 2008-01-23 2010-12-08 엘지전자 주식회사 A method and an apparatus for processing an audio signal
EP2083584B1 (en) * 2008-01-23 2010-09-15 LG Electronics Inc. A method and an apparatus for processing an audio signal
US8615316B2 (en) * 2008-01-23 2013-12-24 Lg Electronics Inc. Method and an apparatus for processing an audio signal
WO2009116280A1 (en) * 2008-03-19 2009-09-24 パナソニック株式会社 Stereo signal encoding device, stereo signal decoding device and methods for them
KR101614160B1 (en) 2008-07-16 2016-04-20 한국전자통신연구원 Apparatus for encoding and decoding multi-object audio supporting post downmix signal
EP2154911A1 (en) * 2008-08-13 2010-02-17 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. An apparatus for determining a spatial output multi-channel audio signal
KR101335975B1 (en) * 2008-08-14 2013-12-04 돌비 레버러토리즈 라이쎈싱 코오포레이션 A method for reformatting a plurality of audio input signals
EP2351024A1 (en) * 2008-10-01 2011-08-03 GVBB Holdings S.A.R.L Decoding apparatus, decoding method, encoding apparatus, encoding method, and editing apparatus
EP2175670A1 (en) 2008-10-07 2010-04-14 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Binaural rendering of a multi-channel audio signal
WO2010042024A1 (en) * 2008-10-10 2010-04-15 Telefonaktiebolaget Lm Ericsson (Publ) Energy conservative multi-channel audio coding
KR101513042B1 (en) * 2008-12-02 2015-04-17 엘지전자 주식회사 Method of signal transmission and signal transmission apparatus
JP5309944B2 (en) * 2008-12-11 2013-10-09 富士通株式会社 Audio decoding apparatus, method, and program
EP2380172B1 (en) 2009-01-16 2013-07-24 Dolby International AB Cross product enhanced harmonic transposition
US20100324915A1 (en) * 2009-06-23 2010-12-23 Electronic And Telecommunications Research Institute Encoding and decoding apparatuses for high quality multi-channel audio codec
US8774417B1 (en) * 2009-10-05 2014-07-08 Xfrm Incorporated Surround audio compatibility assessment
EP2323130A1 (en) * 2009-11-12 2011-05-18 Koninklijke Philips Electronics N.V. Parametric encoding and decoding
JP5604933B2 (en) * 2010-03-30 2014-10-15 富士通株式会社 Downmix apparatus and downmix method
PL3779977T3 (en) * 2010-04-13 2023-11-06 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Audio decoder for processing stereo audio using a variable prediction direction
DE102010015630B3 (en) * 2010-04-20 2011-06-01 Institut für Rundfunktechnik GmbH Method for generating a backwards compatible sound format
MX2013010537A (en) * 2011-03-18 2014-03-21 Koninkl Philips Nv Audio encoder and decoder having a flexible configuration functionality.
RU2618383C2 (en) * 2011-11-01 2017-05-03 Конинклейке Филипс Н.В. Encoding and decoding of audio objects
US9131313B1 (en) * 2012-02-07 2015-09-08 Star Co. System and method for audio reproduction
EP2645748A1 (en) 2012-03-28 2013-10-02 Thomson Licensing Method and apparatus for decoding stereo loudspeaker signals from a higher-order Ambisonics audio signal
CN104364842A (en) * 2012-04-18 2015-02-18 诺基亚公司 Stereo audio signal encoder
US9288603B2 (en) 2012-07-15 2016-03-15 Qualcomm Incorporated Systems, methods, apparatus, and computer-readable media for backward-compatible audio coding
US9473870B2 (en) 2012-07-16 2016-10-18 Qualcomm Incorporated Loudspeaker position compensation with 3D-audio hierarchical coding
US9516446B2 (en) 2012-07-20 2016-12-06 Qualcomm Incorporated Scalable downmix design for object-based surround codec with cluster analysis by synthesis
US9761229B2 (en) 2012-07-20 2017-09-12 Qualcomm Incorporated Systems, methods, apparatus, and computer-readable media for audio object clustering
JP2015529415A (en) * 2012-08-16 2015-10-05 タートル ビーチ コーポレーション System and method for multidimensional parametric speech
RU2676242C1 (en) * 2013-01-29 2018-12-26 Фраунхофер-Гезелльшафт Цур Фердерунг Дер Ангевандтен Форшунг Е.Ф. Decoder for formation of audio signal with improved frequency characteristic, decoding method, encoder for formation of encoded signal and encoding method using compact additional information for selection
US9818412B2 (en) 2013-05-24 2017-11-14 Dolby International Ab Methods for audio encoding and decoding, corresponding computer-readable media and corresponding audio encoder and decoder
CA3211308A1 (en) 2013-05-24 2014-11-27 Dolby International Ab Coding of audio scenes
US10499176B2 (en) 2013-05-29 2019-12-03 Qualcomm Incorporated Identifying codebooks to use when coding spatial components of a sound field
EP2830061A1 (en) 2013-07-22 2015-01-28 Fraunhofer Gesellschaft zur Förderung der angewandten Forschung e.V. Apparatus and method for encoding and decoding an encoded audio signal using temporal noise/patch shaping
EP2830051A3 (en) * 2013-07-22 2015-03-04 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Audio encoder, audio decoder, methods and computer program using jointly encoded residual signals
TWI634547B (en) 2013-09-12 2018-09-01 瑞典商杜比國際公司 Decoding method, decoding device, encoding method, and encoding device in multichannel audio system comprising at least four audio channels, and computer program product comprising computer-readable medium
EP2866227A1 (en) 2013-10-22 2015-04-29 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Method for decoding and encoding a downmix matrix, method for presenting audio content, encoder and decoder for a downmix matrix, audio encoder and audio decoder
KR102160254B1 (en) 2014-01-10 2020-09-25 삼성전자주식회사 Method and apparatus for 3D sound reproducing using active downmix
US9344825B2 (en) * 2014-01-29 2016-05-17 Tls Corp. At least one of intelligibility or loudness of an audio program
US9922656B2 (en) 2014-01-30 2018-03-20 Qualcomm Incorporated Transitioning of ambient higher-order ambisonic coefficients
US10770087B2 (en) 2014-05-16 2020-09-08 Qualcomm Incorporated Selecting codebooks for coding vectors decomposed from higher-order ambisonic audio signals
EP3067885A1 (en) * 2015-03-09 2016-09-14 Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. Apparatus and method for encoding or decoding a multi-channel signal
WO2016142002A1 (en) 2015-03-09 2016-09-15 Fraunhofer-Gesellschaft Zur Foerderung Der Angewandten Forschung E.V. Audio encoder, audio decoder, method for encoding an audio signal and method for decoding an encoded audio signal
EP3295687B1 (en) * 2015-05-14 2019-03-13 Dolby Laboratories Licensing Corporation Generation and playback of near-field audio content
PT3539127T (en) * 2016-11-08 2020-12-04 Fraunhofer Ges Forschung Downmixer and method for downmixing at least two channels and multichannel encoder and multichannel decoder
CN111034225B (en) * 2017-08-17 2021-09-24 高迪奥实验室公司 Audio signal processing method and apparatus using ambisonic signal
CN111615044B (en) * 2019-02-25 2021-09-14 宏碁股份有限公司 Energy distribution correction method and system for sound signal
CN113544774B (en) * 2019-03-06 2024-08-20 弗劳恩霍夫应用研究促进协会 Down-mixer and down-mixing method
US10779105B1 (en) 2019-05-31 2020-09-15 Apple Inc. Sending notification and multi-channel audio over channel limited link for independent gain control

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0688113A2 (en) * 1994-06-13 1995-12-20 Sony Corporation Method and apparatus for encoding and decoding digital audio signals and apparatus for recording digital audio
US5701346A (en) * 1994-03-18 1997-12-23 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Method of coding a plurality of audio signals

Family Cites Families (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5040217A (en) * 1989-10-18 1991-08-13 At&T Bell Laboratories Perceptual coding of audio signals
EP0631458B1 (en) * 1993-06-22 2001-11-07 Deutsche Thomson-Brandt Gmbh Method for obtaining a multi-channel decoder matrix
DE69428939T2 (en) * 1993-06-22 2002-04-04 Deutsche Thomson-Brandt Gmbh Method for maintaining a multi-channel decoding matrix
CA2124379C (en) 1993-06-25 1998-10-27 Thomas F. La Porta Distributed processing architecture for control of broadband and narrowband communications networks
JP3397001B2 (en) * 1994-06-13 2003-04-14 ソニー株式会社 Encoding method and apparatus, decoding apparatus, and recording medium
EP1251501B1 (en) 1995-10-09 2004-09-08 Matsushita Electric Industrial Co., Ltd. An optical disk with an optical barcode and reproduction apparatus
JP3790550B2 (en) 1996-02-08 2006-06-28 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴイ 7-channel transmission compatible with 5-channel transmission and 2-channel transmission
US5812971A (en) * 1996-03-22 1998-09-22 Lucent Technologies Inc. Enhanced joint stereo coding method using temporal envelope shaping
DE19628293C1 (en) * 1996-07-12 1997-12-11 Fraunhofer Ges Forschung Encoding and decoding audio signals using intensity stereo and prediction
SG54379A1 (en) * 1996-10-24 1998-11-16 Sgs Thomson Microelectronics A Audio decoder with an adaptive frequency domain downmixer
US6449368B1 (en) * 1997-03-14 2002-09-10 Dolby Laboratories Licensing Corporation Multidirectional audio decoding
JP3657120B2 (en) 1998-07-30 2005-06-08 株式会社アーニス・サウンド・テクノロジーズ Processing method for localizing audio signals for left and right ear audio signals
JP2000214887A (en) * 1998-11-16 2000-08-04 Victor Co Of Japan Ltd Sound coding device, optical record medium sound decoding device, sound transmitting method and transmission medium
US6928169B1 (en) * 1998-12-24 2005-08-09 Bose Corporation Audio signal processing
US6442517B1 (en) * 2000-02-18 2002-08-27 First International Digital, Inc. Methods and system for encoding an audio sequence with synchronized data and outputting the same
JP4304401B2 (en) * 2000-06-07 2009-07-29 ソニー株式会社 Multi-channel audio playback device
US20030035553A1 (en) 2001-08-10 2003-02-20 Frank Baumgarte Backwards-compatible perceptual coding of spatial cues
US7116787B2 (en) 2001-05-04 2006-10-03 Agere Systems Inc. Perceptual synthesis of auditory scenes
US7006636B2 (en) 2002-05-24 2006-02-28 Agere Systems Inc. Coherence-based audio coding and synthesis
JP4062905B2 (en) * 2001-10-24 2008-03-19 ヤマハ株式会社 Digital mixer
US7333930B2 (en) * 2003-03-14 2008-02-19 Agere Systems Inc. Tonal analysis for perceptual audio coding using a compressed spectral representation
US7394903B2 (en) * 2004-01-20 2008-07-01 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Apparatus and method for constructing a multi-channel output signal or for generating a downmix signal
EP1817767B1 (en) * 2004-11-30 2015-11-11 Agere Systems Inc. Parametric coding of spatial audio with object-based side information

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5701346A (en) * 1994-03-18 1997-12-23 Fraunhofer-Gesellschaft Zur Forderung Der Angewandten Forschung E.V. Method of coding a plurality of audio signals
EP0688113A2 (en) * 1994-06-13 1995-12-20 Sony Corporation Method and apparatus for encoding and decoding digital audio signals and apparatus for recording digital audio

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
FALLER C ET AL: "BINAURAL CUE CODING APPLIED TO STEREO AND MULTI-CHANNEL AUDIO COMPRESSION" PREPRINTS OF PAPERS PRESENTED AT THE AES CONVENTION, XX, XX, vol. 112, no. 5574, 10 May 2002 (2002-05-10), XP009024737 *
HERRE J ET AL: "INTENSITY STEREO CODING" PREPRINTS OF PAPERS PRESENTED AT THE AES CONVENTION, XX, XX, vol. 96, no. 3799, 26 February 1994 (1994-02-26), pages 1-10, XP009025131 *

Cited By (48)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100848367B1 (en) * 2004-04-16 2008-07-24 코딩 테크놀러지스 에이비 Apparatus and method for generating a level parameter and apparatus and method for generating a multi-channel representation
JP2008517337A (en) * 2004-11-02 2008-05-22 コーディング テクノロジーズ アクチボラゲット A method for improving the performance of prediction-based multi-channel reconstruction
US8515083B2 (en) 2004-11-02 2013-08-20 Dolby International Ab Methods for improved performance of prediction based multi-channel reconstruction
JP2008542815A (en) * 2005-05-26 2008-11-27 エルジー エレクトロニクス インコーポレイティド Audio signal decoding method and apparatus
US8280743B2 (en) 2005-06-03 2012-10-02 Dolby Laboratories Licensing Corporation Channel reconfiguration with side information
JP2008543227A (en) * 2005-06-03 2008-11-27 ドルビー・ラボラトリーズ・ライセンシング・コーポレーション Reconfiguration of channels with side information
TWI424754B (en) * 2005-06-03 2014-01-21 Dolby Lab Licensing Corp Channel reconfiguration with side information
JP2009501957A (en) * 2005-07-19 2009-01-22 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Multi-channel audio signal generation
US8160888B2 (en) 2005-07-19 2012-04-17 Koninklijke Philips Electronics N.V Generation of multi-channel audio signals
JP4859925B2 (en) * 2005-08-30 2012-01-25 エルジー エレクトロニクス インコーポレイティド Audio signal decoding method and apparatus
JP2009506706A (en) * 2005-08-30 2009-02-12 エルジー エレクトロニクス インコーポレイティド Audio signal decoding method and apparatus
TWI462086B (en) * 2005-09-14 2014-11-21 Lg Electronics Inc Method and apparatus for decoding an audio signal
TWI485698B (en) * 2005-09-14 2015-05-21 Lg Electronics Inc Method and apparatus for decoding an audio signal
US9747905B2 (en) 2005-09-14 2017-08-29 Lg Electronics Inc. Method and apparatus for decoding an audio signal
US9934789B2 (en) 2006-01-11 2018-04-03 Samsung Electronics Co., Ltd. Method, medium, and apparatus with scalable channel decoding
JP2009526258A (en) * 2006-02-07 2009-07-16 エルジー エレクトロニクス インコーポレイティド Encoding / decoding apparatus and method
US9626976B2 (en) 2006-02-07 2017-04-18 Lg Electronics Inc. Apparatus and method for encoding/decoding signal
JP2009526262A (en) * 2006-02-07 2009-07-16 エルジー エレクトロニクス インコーポレイティド Encoding / decoding apparatus and method
US9848180B2 (en) 2006-03-06 2017-12-19 Samsung Electronics Co., Ltd. Method, medium, and system generating a stereo signal
WO2007102675A1 (en) * 2006-03-06 2007-09-13 Samsung Electronics Co., Ltd. Method, medium, and system generating a stereo signal
US8620011B2 (en) 2006-03-06 2013-12-31 Samsung Electronics Co., Ltd. Method, medium, and system synthesizing a stereo signal
KR100773562B1 (en) * 2006-03-06 2007-11-07 삼성전자주식회사 Method and apparatus for generating stereo signal
US9479871B2 (en) 2006-03-06 2016-10-25 Samsung Electronics Co., Ltd. Method, medium, and system synthesizing a stereo signal
KR100773560B1 (en) * 2006-03-06 2007-11-05 삼성전자주식회사 Method and apparatus for synthesizing stereo signal
WO2007102674A1 (en) * 2006-03-06 2007-09-13 Samsung Electronics Co., Ltd. Method, medium, and system synthesizing a stereo signal
US9087511B2 (en) 2006-03-06 2015-07-21 Samsung Electronics Co., Ltd. Method, medium, and system for generating a stereo signal
US8948405B2 (en) 2006-06-02 2015-02-03 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10091603B2 (en) 2006-06-02 2018-10-02 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US12052558B2 (en) 2006-06-02 2024-07-30 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US11601773B2 (en) 2006-06-02 2023-03-07 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
JP4834153B2 (en) * 2006-06-02 2011-12-14 ドルビー インターナショナル アクチボラゲット Binaural multichannel decoder in the context of non-energy-saving upmix rules
US8027479B2 (en) 2006-06-02 2011-09-27 Coding Technologies Ab Binaural multi-channel decoder in the context of non-energy conserving upmix rules
JP2009539283A (en) * 2006-06-02 2009-11-12 ドルビー スウェーデン アクチボラゲット Binaural multichannel decoder in the context of non-energy-saving upmix rules
US9992601B2 (en) 2006-06-02 2018-06-05 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving up-mix rules
US10015614B2 (en) 2006-06-02 2018-07-03 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10021502B2 (en) 2006-06-02 2018-07-10 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10085105B2 (en) 2006-06-02 2018-09-25 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10863299B2 (en) 2006-06-02 2020-12-08 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10097940B2 (en) 2006-06-02 2018-10-09 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10097941B2 (en) 2006-06-02 2018-10-09 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10123146B2 (en) 2006-06-02 2018-11-06 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10412526B2 (en) 2006-06-02 2019-09-10 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10412525B2 (en) 2006-06-02 2019-09-10 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10412524B2 (en) 2006-06-02 2019-09-10 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US10469972B2 (en) 2006-06-02 2019-11-05 Dolby International Ab Binaural multi-channel decoder in the context of non-energy-conserving upmix rules
US8885854B2 (en) 2006-08-09 2014-11-11 Samsung Electronics Co., Ltd. Method, medium, and system decoding compressed multi-channel signals into 2-channel binaural signals
US8170218B2 (en) 2007-10-04 2012-05-01 Hurtado-Huyssen Antoine-Victor Multi-channel audio treatment system and method
CN104486033A (en) * 2014-12-03 2015-04-01 重庆邮电大学 Downlink multimode channel coding system and method based on C-RAN platform

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