EP0891617B1 - System zur kodierung und dekodierung eines signals, insbesondere eines digitalen audiosignals - Google Patents

System zur kodierung und dekodierung eines signals, insbesondere eines digitalen audiosignals Download PDF

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Publication number
EP0891617B1
EP0891617B1 EP97919457A EP97919457A EP0891617B1 EP 0891617 B1 EP0891617 B1 EP 0891617B1 EP 97919457 A EP97919457 A EP 97919457A EP 97919457 A EP97919457 A EP 97919457A EP 0891617 B1 EP0891617 B1 EP 0891617B1
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primary
flow
bank
encoder
frame
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EP0891617A1 (de
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Laurent Mainard
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Telediffusion de France ets Public de Diffusion
Orange SA
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Telediffusion de France ets Public de Diffusion
France Telecom SA
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    • 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
    • G10L19/04—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 predictive techniques
    • G10L19/16—Vocoder architecture
    • 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
    • G10L25/00—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00
    • G10L25/03—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters
    • G10L25/18—Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 characterised by the type of extracted parameters the extracted parameters being spectral information of each sub-band

Definitions

  • the present invention relates to a coding and decoding of a signal, in particular of a digital audio signal.
  • These systems find application in low speed transmission of audio signals, with a coding / decoding delay constraint as low as possible imposed for example by the return of a voice control.
  • the present invention is concerned by the antinomy between, on the one hand, the search for a quality of transmission which generally entails for a fixed speed a delay of relatively long coding and decoding and, on the other hand, the delay of coding / decoding which, in some applications, must be short.
  • the term delay coding / decoding the time between the entry of a sample into the encoder of the sample output corresponding to the decoder.
  • the coding process and / or the structure of the circuits which allow this coding will consider that the calculations made during these processes are infinitely fast both within the encoder and the decoder. Alone are therefore taken into account in the calculation of the coding / decoding delay parameters such as the duration of acquisition of signal frames digital, the delay imposed by a filter bank and / or the duration corresponding to a multiplexing of samples.
  • this delay will be greater than the duration of a coded frame added to the delay generated by the transform.
  • a low delay coder of the LD-CELP type such as that described by JHChen and all in the article entitled "A low delay CELP coder for the CCITT 16kb / s speech coding standard" published in IEEE J. Salt. Areas Commun., Vol 10, pp 830-849
  • the delay is linked to the five samples constituting a basic frame.
  • the quality of coding it is a parameter which is difficult to define, knowing that the final receiver, i.e. the ear of the auditor cannot give precise quantitative results.
  • measurements such as the signal-to-noise ratio do not are irrelevant because they do not take into account the properties of psycho-acoustic masking of the auditory system.
  • Techniques statistics such as those recommended by ITU-R-BS-1116 differentiate between different coding algorithms with regard to the quality of coding.
  • Coding systems for generic digital audio signals that is to say without assumption on the mode of production of these signals, have so far taken as little constraint the time aspect of signal reconstruction.
  • An exception is however illustrated by the process which is described by F. Rumseyi in an article entitled “Hearing both sides-stereo sound for TV in the UK” published in IEE rev, vol 36, No 5, pp173-176.
  • the rates of compression achieved do not allow to compete with coders to classic transforms.
  • the minimum reconstruction times range from 18 ms for the simplest - and therefore least efficient - encoder at more than 100 ms for the most complex coder.
  • Other non-coding methods standardized by ISO such as the so-called AC3 process described by C. Todd and all, such as the process known as ASPEC (Adaptive Spectral Perceptual Entropy Coding) described by K. Brandebug and all, or the method said ATRAC (Adaptive Transform Acoustic Coding) described by K. Tsutsui typically have coding / decoding delays of the order of one hundred milliseconds.
  • the effectiveness of coding systems is linked to the size of the filter banks which are generally used, taking into account long-term redundancies in the signals to be coded, at the optimal distribution of binary allocations over a period higher than the frame, etc. Taking these elements into account when coding time increases the delay system coding / decoding.
  • low delay coders are often linked to coding speech for duplex telephone links, for example, or to be associated with echo cancellers. Most often designed for sampling frequencies from 8 kHz to 16 kHz, their level of quality is insufficient to code in a manner close to the original of the generic digital audio signals.
  • the object of the invention is to propose, in this context, a coding system and the associated decoding system which allows, receiver side, to reconstruct both a digital audio signal from quality and a lower quality digital audio signal but whose encoding / decoding delay is as short as possible.
  • Such coding systems include an encoder for coding a high quality sound signal the output of which is connected to the input of a decoder and a difference circuit which makes the difference between the signal obtained at the output of the decoder and the signal d 'origin.
  • the difference signal is itself subjected, in a second stage, to coding, decoding and analogous difference calculation treatments.
  • the third stage codes the residual difference signal.
  • the signals from the encoders of the three stages are then multiplexed so as to form a hierarchical digital stream.
  • the coder is a low bit rate coder which has a relatively low coding delay.
  • the second stage encoder is a longer delay encoder.
  • each encoder actually consists of a sub-sampled filter bank and an encoder.
  • each decoder is actually consisting of a decoder, a bank of filters associated with the bank of encoder and oversampler filters.
  • the object of the invention is to propose a coding system which has a lower low quality stream coding / decoding delay to the one given by the system described above.
  • a coding system is characterized in that it comprises a filter bank provided for receive said incoming stream to be encoded and to generate signals respectively in different sub-bands, so-called coders primary coders, for respectively coding said signals into sub-bands and thus form primary streams, decoders receiving said primary streams and decoding said streams, subtractors each of which is intended to make the difference between the signals delivered by the filter bank in a sub-band and the signals from the corresponding decoder, an encoder, called an encoder secondary, to code the signals from the subtractors, and thus generate a secondary flow, and a multiplexer to multiplex the streams into a single global stream primary from primary encoders and the secondary stream from secondary encoder.
  • coders primary coders for respectively coding said signals into sub-bands and thus form primary streams
  • decoders receiving said primary streams and decoding said streams
  • subtractors each of which is intended to make the difference between the signals delivered by the filter bank in a sub-band and the signals from the corresponding decoder
  • Said secondary filter bank advantageously comprises, for each sub-band, an entry for receive the primary stream from the primary encoder and decode by the corresponding decoder to determine, using a model psycho-acoustic, maximum levels of injectable noise in each of the sub-bands, said secondary encoder being an encoder perceptual whose coding is based on psycho-acoustic analysis performed by said secondary filter bank.
  • said bench secondary filters includes, for each sub-band, an entry for receive the signal in sub-bands from the primary filter bank in order to determine, using a psycho-acoustic model, the maximum levels of injectable noise in each of the sub-bands, said secondary coder being a perceptual coder whose coding is based on the psycho-acoustic analysis carried out by said bench secondary filters.
  • each primary coder is a coder reconfigurable in debit.
  • the present invention also relates to a method of multiplexing of a primary frame with a secondary frame generated by a coding system of a signal to be coded, of the type delivering a global flow consisting of a primary flow corresponding to coding of an incoming stream, called primary coding, and of a stream secondary corresponding to secondary coding
  • It consists in constituting a frame called global frame constituted by the concatenation of a plurality of primary frames and a plurality of fragments of at least one secondary frame, one frame primary alternating with a secondary frame fragment, the number of bits of a secondary frame fragment being equal to the bit rate allocated to the secondary flow multiplied by the duration of transmission of a frame primary.
  • the transmission of global frames is advantageously done all the durations of the primary frames.
  • the duration of a frame global is equal to the duration of transmission of a primary frame multiplied by the number of primary frames.
  • the present invention also relates to a decoding system a stream encoded by a coding system such as the one described above. It includes a flow demultiplexer delivering a plurality of primary streams and a secondary stream, a plurality of primary decoders for decoding said primary streams, the output of each decoder being connected to a corresponding input of a bench primary filters then delivering a low delay decoded stream, the output of each decoder also being connected to an input from one line to corresponding delay whose output is linked to the first input a summator, a secondary decoder delivering a secondary stream decoded supplied to a second input of each adder, the output of each adder being connected to the input of a second filter bank primary to deliver a high quality decoded stream. It comprises in addition a secondary filter bank.
  • the coding system shown in FIG. 1 consists of a filter bank 10, the input of which receives an incoming digital audio stream FE to be coded.
  • the filter bank 10 delivers several signals located in different sub-bands, called primary sub-bands. These signals are respectively supplied to the inputs of low-speed primary encoders 20 1 to 20 4 , here four in number but may be in any number n greater than two.
  • each decoder 40 i is connected to a first input of a subtractor 50 i , the other input of which receives the signal from the corresponding primary sub-band delivered by the filter bank 10.
  • the difference signal from the subtractor 50 i is supplied to the input of a secondary filter bank 60, the output of which is connected to an encoder 70.
  • the output of the encoder 70 is connected to a corresponding input of the multiplexer 30.
  • Multiplexer 30 interleaves primary flows and secondary respectively from coders 20 and 70.
  • FIG. 2 illustrates the interleaving process.
  • Two time axes have been shown, one of which is expanded relative to the second, dotted lines showing the time correspondence between these axes.
  • On the first axis are represented segments whose length corresponds to the duration of establishment t of a primary frame obtained by association of the four primary streams coming from coders 20 1 to 20 4 .
  • On the other axis there is shown a global frame TG consisting of a header H, four primary frames TP and four fragments of a secondary frame FTS, the fragments of secondary frame FTS alternating with the primary frames TP.
  • the fragments of secondary frame FTS are the result of a fragmentation of the secondary frame TS delivered by the secondary coder 70.
  • the number of bits of a fragment FTS is equal to the bit rate allocated to the secondary stream multiplied by the duration t of transmission primary coders.
  • the duration Tt of the global frame TG is an integer multiple of the duration t of the primary frame mentioned above (here four).
  • the duration Tt of the global frame TG is an integer multiple of the duration T of the secondary frame TS.
  • the duration of the overall frame Tt is equal to the duration T of a secondary frame TS. In this case, only one secondary frame TS is included in the global frame TG, as is the case in FIG. 2.
  • the number of primary frames TP and the number of fragments of secondary frames TS ar global frame could be different from four without fundamentally changing the concept of the invention. In particular, this number is not linked to the number of sub-bands contained in a primary frame.
  • the emission of the global flow is done all the durations of the frames primary TP. More precisely, for each program, the information of a primary frame TP and of the frame fragment secondary FTS consecutive.
  • the bit rate allocated to each primary coder 20 i is variable. This allocation is known to both the coding system and the decoding system. For example, we could decide the allocation according to the energy in each primary sub-band.
  • the header H contains a synchronization word for setting the decoding system and for delivering the allocations of the different primary coders 20 i . These frame header allocations sent by the coding system are then used to initialize the decoding system and to remedy any transmission errors.
  • the filter bank 60 For each sub-band of the filter bank 10, the filter bank 60 has an input for receiving the concerned sub-band delivered by the primary filter bank 10. From this signal, a model suitable psycho-acoustic, for example the first model proposed by ISO / IEC 13818-3, will determine the maximum noise levels inaudible injectable into each of the sub-bands secondary.
  • a model suitable psycho-acoustic for example the first model proposed by ISO / IEC 13818-3, will determine the maximum noise levels inaudible injectable into each of the sub-bands secondary.
  • the encoder 70 is a perceptible encoder whose coding is based on the psycho-acoustic analysis provided by the filter bank 60.
  • the stream of the primary coder 20 i has a sufficient number of bits, for example 2.5 bits per sample, it is preferable to replace the original signal at the input of the filter bank for processing according to the psycho-acoustic model by its coded then decoded version delivered by the decoder 40 i in the primary sub-band considered.
  • the advantage is that the secondary decoder of the decoding system which is associated with the present coding system and which is therefore provided with the same psycho-acoustic model as the filter bank 60 can deduce the fine allocation levels calculated by the secondary coder 70. This saves on transmission costs.
  • the primary filter bank may be a filter bank of the family of QMF (Quadrature Mirror Filterbank) or benches MOT (Modulated Orthogonal Transforms) filters, with a number enough subbands not to produce a delay too late.
  • QMF Quadrature Mirror Filterbank
  • benches MOT Modulated Orthogonal Transforms
  • a bank of filters modulated in sub-bands of uneven widths or a wavelet type cascaded filter bank or others is also possible, provided that this choice is compatible with the deadline.
  • a filter bank with eight sub-bands modulated from a filter of length thirty two such as the one described by H.S.
  • Each low delay coder 20 i can be a coder reconfigurable in bit rate so that the bit rate associated with each sub-band is variable.
  • Each coder 20 i generates a stream over a small number of grouped samples, representing a constant duration independent of the sub-band. This duration will hereinafter be called the primary duration.
  • LD-CELP Low Delay - Code Excited Linear Prediction
  • This LD-CELP coder can contain a choice of dictionaries of different sizes.
  • each decoder 40 i it will be noted that it could be included in the associated coder 20 i .
  • the secondary filter bank 60 its choice is freer than for the primary filter bank 10 since where there is no constraint on the delay it introduced.
  • a filter bank can deliver a variable number of sub-bands by primary sub-band, according to the stationarity of the subband signal.
  • aliasing reduction butterflies such as those described by 8. Tang and all in an article entitled "Spectral analysis of subband filtered signals "published in ICAASP, Vol 2, pp 1324-1327, 1995.
  • a bank of MOT type filters Modulated Orthogonal Transforms
  • WORD type filter bank
  • the bit rate available for the secondary encoder 70 is calculated by subtracting the bit rate used by the low delay primary encoders 20 i from the total bit rate. For example, for a total bit rate of 64 kbits / s, it would be possible to allocate 32 kbits / s to all of the primary coders 20 1 to 20 n and 32 kbits / s to the secondary coder 70.
  • the decoding system shown in FIG. 3 is made up of elements whose references are between 110 and 180. Each element is the dual of an element of the coding system shown in FIG. 1 with the exception of elements 180 i . Its reference is then the same plus a hundred.
  • the demultiplexer 130 is the dual of the multiplexer 30.
  • one element is the dual of another element when intended to perform the reverse function of this first.
  • the decoding system shown in FIG. 3 consists of a demultiplexer 130 whose outputs are respectively connected to the inputs of primary decoders 120 1 to 120 4 and to a secondary coder 170.
  • each primary decoder 120 1 to 120 4 is connected, on the one hand, to an associated delay line 180 1 to 180 4 and, on the other hand, to an input of a first primary filter bank 110.
  • the output of the filter bank 110 delivers the decoded primary flow Fd.
  • the primary stream decoded Fd is the stream of lower quality but of weak coding / decoding delay.
  • each delay line 180 1 to 180 4 is connected to a first input of a corresponding adder 150 1 to 150 4 .
  • the output of the secondary decoder 170 is connected to the input of a filter bank 160 whose outputs are respectively connected to the second inputs of the adders 150 1 to 150 4 .
  • the outputs of the adders 150 1 to 150 4 are respectively connected to the corresponding inputs of a filter bank 110 ′ whose output delivers the high quality decoded stream Fdhq.
  • a link between each delay line 180 i and the decoder 170 is provided so as to transmit to the latter, at the desired time, the allocation information present in the primary stream originating from the corresponding decoder 120j.
  • the demultiplexer 130 of the decoding system realizes the separation of the global frame TG received into primary frames TP and into a secondary frame delivered alternately to the primary decoders 120 1 to 120 4 and to the secondary decoder 170.
  • the low delay output of the decoding system is obtained by decoding, in the primary decoders 120 i , primary frames into sub-bands then passing through the reciprocal filter bank 110 of the low-delay filter bank 10.
  • the primary stream originating from the primary decoder 120 i and the allocation information it contains are sent to the corresponding 180 i delay line to supply the high quality part.
  • the allocation information from the delay lines is transmitted, for each primary stream, to the secondary decoder 170 which then performs a decoding of the secondary frame.
  • the reciprocal aliasing reducing butterflies of the coding butterflies are then applied, then the secondary filter bank 160.
  • the signals received from the primary decoders 120 i are then added via the delay lines 180 i to supply the primary filter bank 110 ' .
  • the high quality Fdhq signal is recovered at the output.

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  • Engineering & Computer Science (AREA)
  • Computational Linguistics (AREA)
  • Signal Processing (AREA)
  • Health & Medical Sciences (AREA)
  • Audiology, Speech & Language Pathology (AREA)
  • Human Computer Interaction (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)

Claims (10)

  1. System zur Kodierung eines zu kodierenden Signals, welches einen Gesamtfluß liefert, der von einem primären Fluß, der einer Kodierung eines eingehenden Flusses, Primärkodierung genannt, entspricht, und von einem sekundären Fluß gebildet wird, der einer Sekundärkodierung entspricht, wobei die Kodierzeit der Primärkodierung kleiner ist als die der Sekundärkodierung, dadurch gekennzeichnet, daß es eine Filterbank (10), die dazu vorgesehen ist, den zu kodierenden eingehenden Fluß (FE) zu empfangen und Signale jeweils in unterschiedlichen Unterbändern der Kodierer, Primärkodierer (201 bis 204) genannt, zu erzeugen, um die Signale in Unterbändern zu kodieren und auf diese Weise Primärflüsse (TP) zu bilden, wobei Dekoder (401 bis 404) die Primärflüsse (TP) empfangen und diese Flüsse dekodieren, Subtrahierglieder (501 bis 504), von denen jedes dazu vorgesehen ist, die Differenz zwischen den von der Filterbank (10) in jedem Unterband gelieferten Signalen und den von dem entsprechenden Dekoder (401 bis 404) gelieferten Signalen zu erstellen, einen Kodierer (70), genannt Sekundärkodierer, um die Kodierung der von den Subtrahiergliedern (501 bis 504) gekommenen Signale durchzuführen und auf diese Weise einen Sekundärfluß (TS) zu erzeugen, und einen Multiplexer (30) umfaßt, um in einem einzigen Gesamtfluß (TG) die Primärflüsse (TP), die von den Primärkodierern (201 bis 204) gekommen sind, und den Sekundärfluß (TS), der von dem Sekundärkodierer (70) gekommen ist, zu multiplexen.
  2. Kodiersystem nach Anspruch 1, dadurch gekennzeichnet, daß es eine zweite Filterbank (60), genannt Sekundärfilterbank, umfaßt, die an jedem ihrer Eingänge das Differenzsignal empfängt, das von jedem Subtrahierglied (501 bis 504) ausgegangen ist, und die einen gefilterten Fluß an den Eingang des Sekundärkodierers (70) liefert.
  3. Kodiersystem nach Anspruch 2, dadurch gekennzeichnet, daß die Sekundärfilterbank (60) für jedes Unterband einen Eingang umfaßt, um den Primärfluß (TP), der von dem Primärkodierer (201 bis 204) gekommen ist und von dem entsprechenden Dekoder (401 bis 404) dekodiert wurde, zu empfangen, um mit Hilfe eines psychoakustischen Modells die maximalen Lärmniveaus zu bestimmen, die in jedes der Unterbänder eingeleitet werden können, wobei der Sekundärkodierer (70) ein Wahrnehmungskodierer ist, dessen Kodierung auf der psychoakustischen Analyse beruht, die von der Sekundärfilterbank (60) durchgeführt wurde.
  4. Kodiersystem nach Anspruch 2, dadurch gekennzeichnet, daß die Sekundärfilterbank (60) für jedes Unterband einen Eingang umfaßt, um das Unterbandsignal, das von der Primärfilterbank (10) gekommen ist, zu empfangen, um mit Hilfe eines psychoakustischen Modells die maximalen Lärmniveaus zu bestimmen, die in jedes der Unterbänder eingeleitet werden können, wobei der Sekundärkodierer (70) ein Wahrnehmungskodierer ist, dessen Kodierung auf der psychoakustischen Analyse beruht, die von der Sekundärfilterbank (60) durchgeführt wurde.
  5. Kodiersystem nach einem der vorhergehenden Ansprüche, dadurch gekennzeichnet, daß jeder Primärkodierer (201 bis 204) ein bezüglich der Durchgangsmenge rekonfigurierbarer Kodierer ist.
  6. Multiplexing-Verfahren eines Primärrasters (TP) mit einem Sekundärraster (TS), die durch ein Kodiersystem eines zu kodierenden Signals erzeugt werden, das einen Gesamtfluß liefert, der von einem Primärfluß, der einer Kodierung des eingehenden Flusses, genannt Primärkodierung, entspricht, und einem Sekundärfluß gebildet wird, der einer Sekundärkodierung entspricht, dadurch gekennzeichnet, daß es darin besteht, einen Raster, genannt Gesamtraster (TG), zu bilden, der von der Aneinanderkettung einer Mehrzahl von Primärrastern (TP) und einer Mehrzahl von Fragmenten (FTS) von mindestens einem Sekundärraster (TS) gebildet wird, wobei ein Primärraster (TP) mit einem Sekundärrasterfragment (FTS) abwechselt, wobei die Bitanzahl eines Sekundärrasterfragments (FTS) gleich der dem Sekundärfluß (TS) zugeteilten Durchflußmenge ist, multipliziert mit der Emissionszeit eines Primärrasters (TP).
  7. Multiplexing-Verfahren nach Anspruch 6, dadurch gekennzeichnet, daß die Emission der Gesamtraster (TG) während aller Zeitdauern der Primärraster (TP) erfolgt.
  8. Multiplexing-Verfahren nach Anspruch 6 oder 7, dadurch gekennzeichnet, daß die Dauer eines Gesamtrasters (TG) gleich der Emissionsdauer eines Primärrasters (TP), multipliziert mit der Anzahl von Primärrastern (TP) ist.
  9. Dekodiersystem für einen durch ein Kodiersystem nach einem der Ansprüche 1 bis 5 kodierten Fluß, dadurch gekennzeichnet, daß es einen Flußdemultiplexer (130) umfaßt, der eine Mehrzahl von Primärflüssen und Sekundärflüssen liefert, und eine Mehrzahl von Pirmärdekodern (1201 bis 1204) zur Dekodierung der Primärflüsse umfaßt, wobei der Ausgang jedes Dekoders (1201 bis 1204) mit einem entsprechenden Eingang einer Pirmärfilterbank (110) verbunden ist, die nun einen dekodierten Fluß geringer Verzögerung (Fd) liefert, wobei der Ausgang jedes Dekoders (1201 bis 1204) ebenfalls mit einem Eingang einer entsprechenden Verzögerungsleitung (1801 bis 1804) verbunden ist, deren Ausgang mit dem ersten Eingang eines Summators (1501 bis 1504) verbunden ist, wobei ein Sekundärdekoder (170) einen dekodierten Sekundärfluß liefert, der an einen zweiten Eingang jedes Summators (1501 bis 1504) geliefert wird, wobei der Ausgang jedes Summators (1501 bis 1504) mit dem Eingang einer zweiten Primärfilterbank (110') verbunden ist, um einen dekodierten Fluß hoher Qualität (Fdgh) zu liefern.
  10. Dekodiersystem nach Anspruch 9, dadurch gekennzeichnet, daß es ferner eine Sekundärfilterbank (160) umfaßt.
EP97919457A 1996-04-03 1997-04-02 System zur kodierung und dekodierung eines signals, insbesondere eines digitalen audiosignals Expired - Lifetime EP0891617B1 (de)

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FR9604483A FR2747225B1 (fr) 1996-04-03 1996-04-03 Systeme de codage et systeme de decodage d'un signal, notamment d'un signal audionumerique
FR9604483 1996-04-03
PCT/FR1997/000582 WO1997038417A1 (fr) 1996-04-03 1997-04-02 Systeme de codage et systeme de decodage d'un signal, notamment d'un signal audionumerique

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JP3855827B2 (ja) * 2002-04-05 2006-12-13 ソニー株式会社 ２次元サブバンド符号化装置
US8352248B2 (en) 2003-01-03 2013-01-08 Marvell International Ltd. Speech compression method and apparatus
US7548853B2 (en) * 2005-06-17 2009-06-16 Shmunk Dmitry V Scalable compressed audio bit stream and codec using a hierarchical filterbank and multichannel joint coding
FI20065010A0 (fi) * 2006-01-09 2006-01-09 Nokia Corp Häiriönvaimennuksen yhdistäminen tietoliikennejärjestelmässä

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Publication number Publication date
DE69700837D1 (de) 1999-12-30
WO1997038417A1 (fr) 1997-10-16
DE69700837T2 (de) 2000-07-20
FR2747225B1 (fr) 1998-04-30
EP0891617A1 (de) 1999-01-20
US6058361A (en) 2000-05-02
FR2747225A1 (fr) 1997-10-10

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