EP2179415B1 - Appareil et procédé de codage de couche d'amélioration - Google Patents

Appareil et procédé de codage de couche d'amélioration Download PDF

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EP2179415B1
EP2179415B1 EP08793289A EP08793289A EP2179415B1 EP 2179415 B1 EP2179415 B1 EP 2179415B1 EP 08793289 A EP08793289 A EP 08793289A EP 08793289 A EP08793289 A EP 08793289A EP 2179415 B1 EP2179415 B1 EP 2179415B1
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Prior art keywords
exponent
sample
bits
enhancement layer
additional mantissa
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German (de)
English (en)
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EP2179415A1 (fr
EP2179415A4 (fr
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Jongmo Sung
Do-Young Kim
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Electronics and Telecommunications Research Institute ETRI
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Electronics and Telecommunications Research Institute ETRI
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Priority claimed from KR1020080024919A external-priority patent/KR100912826B1/ko
Application filed by Electronics and Telecommunications Research Institute ETRI filed Critical Electronics and Telecommunications Research Institute ETRI
Priority to EP10153693.6A priority Critical patent/EP2187387B1/fr
Priority to EP10153630A priority patent/EP2202728B1/fr
Publication of EP2179415A1 publication Critical patent/EP2179415A1/fr
Publication of EP2179415A4 publication Critical patent/EP2179415A4/fr
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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
    • G10L19/18—Vocoders using multiple modes
    • G10L19/24—Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding
    • 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
    • G10L19/002—Dynamic bit allocation

Definitions

  • the present invention relates to a G.711 encoder and decoder, and more particularly, to a method of encoding and decoding an enhancement layer to reduce a quantization error in a G.711 codec.
  • PCM pulse coded modulation
  • CELP code-excited linear prediction
  • the log PCM codec uses a small quantization step when the level of an input signal is low, and uses a large quantization step when the level of an input signal is high.
  • the log PCM codec can compress a digital sample with 16 bits per sample to a codeword with 8 bits per sample. Accordingly, if a signal is sampled at 8 KHz, a bit rate of 64,000 bps is obtained using the log PCM codec.
  • the A-law and u-law have been standardized as ITU-T(International Telecommunication Union - Telecommunication Sector) Recommendation G.711 since 1972.
  • the values of ⁇ and A in the G.711 are 255 ( ⁇ ) and 87.56 (A), respectively.
  • the G.711 codec actually uses a floating point quantization method, rather than directly calculates Equation 1.
  • available bits per sample e.g., 8 bits for the G.711
  • some bits are used to determine a quantization step and the remaining bits are used to express a position in the quantization step.
  • the former bits are exponent bits and the latter bits are mantissa bits.
  • 3 bits are used for the exponent
  • 4 bits are used for the mantissa
  • the remaining 1 bit is used to express a sign of a sample.
  • the G.711 provides a high quality of about 4 MOS (Mean Opinion Score) for narrowband speech, with less computational complexity and memory requirements. However, there is still quality degradation caused by quantization error, compared with an original speech signal.
  • MOS Mel Opinion Score
  • the present invention provides an apparatus and method for encoding and decoding an enhancement layer, which can reduce quantization error in a G.711 codec by adding extra bits to each G.711-coded sample.
  • the present invention also provides an enhancement layer encoder and decoder which can reduce quantization error in a G.711 codec.
  • an enhancement layer encoder according to independent claim 7.
  • an encoder according to claim 14 there is provided an encoder according to claim 14.
  • FIG. 1 is a block diagram of an encoder 100 and a decoder 150 for improving the quality of speech in a G.711 codec.
  • the encoder 100 includes an input buffer 105, a G.711 encoding unit 110, an enhancement layer encoding unit 115, and a multiplexing unit 120.
  • the decoder 150 includes a demultiplexing unit 155, a G.711 decoding unit 160, an enhancement layer decoding unit 165, a signal synthesizing unit 170, and an output buffer 175.
  • the encoder 100 is connected to the decoder 150 through a communication channel 140.
  • the encoder 100 will be first explained.
  • the G.711 encoding unit 110 encodes the frame stored in the input buffer 105 using the conventional G.711 codec, and outputs a G.711 bitstream. Since the G.711 is a well-known codec standardized by the ITU-T, a detailed explanation thereof will not be given here.
  • the enhancement layer encoding unit 115 encodes a quantization error, which is not represented by the G.711 encoding unit 110, using additional bits and outputs an enhancement bitstream.
  • the multiplexing unit 120 multiplexes the G.711 bitstream of the G.711 encoding unit 110 and the enhancement bitstream of the enhancement layer encoding unit 115.
  • the multiplexed bitstream is transmitted to the decoder 150 through the communication channel 140.
  • the decoder 150 will now be explained.
  • the demultiplexing unit 155 demultiplexes the multiplexed bitstream received from the encoder 100 through the communication channel 140 to a G.711 bitstream and an enhancement bitstream.
  • the G.711 decoding unit 160 decodes the G.711 bitstream by using the G.711 codec and outputs a G.711 decoded signal.
  • the enhancement layer decoding unit 165 decodes the enhancement bitstream and outputs an enhancement layer decoded signal.
  • the signal synthesizing unit 170 combines the G.711 decoded signal from the G.711 decoding unit 160 and the enhancement layer decoded signal from the enhancement layer decoding unit 165 and outputs a synthesized signal.
  • the output buffer 175 stores the synthesized signal from the signal synthesizing unit 170, and outputs the stored signal in frame-by-frame.
  • FIG. 2 is a schematic view illustrating an input bitstream and an output bitstream of an encoder to which a log PCM codec of a conventional G.711 codec is applied
  • FIG. 3 is a schematic view illustrating an input bitstream and an output bitstream of an encoder to which enhancement layer encoding according to the present invention is applied.
  • the 8-bit sample 250 is composed of 1-bit sign information 260, 3-bit exponent information 270, and 4-bit mantissa information 280.
  • the exponent information 270 indicates a compander segment
  • the mantissa information 280 indicates a position in the segment indicated by the exponent information 270.
  • a coded sample when enhancement layer encoding according to the present invention is used, includes additional mantissa information 390 as well as a G.711-coded sample of 8 bits.
  • the additional mantissa information 390 sub-divides a specific position indicated by mantissa information 380 in a segment indicated by exponent information 370, thereby reducing quantization error resulted from the G.711 codec.
  • the total number of available bits for enhancement layer per frame is 80 bits. That is, when the number of samples in the frame is 40 samples, an additional 2 bits per sample can be allocated on the average. Since a quantization error in the G.711 codec depends on the magnitude of an input signal, it is preferable to dynamically allocating the number of bits for additional mantissa information of each sample according to the magnitude of each sample, rather than to allocate the same number of bits for the additional mantissa information of each sample.
  • bits per sample are allocated to additional mantissa information in order to reduce quantization error further, the total number of bits of all samples in a frame i.e. 120 bits (40 samples * 3 bits) exceeds the available 80 bits.
  • bits ranging from 0 to 3 are allocated to the additional mantissa information based on the exponent value of each sample.
  • the maximum number of bits per sample for the additional mantissa information may be set to 3, or more, or less, depending upon embodiments of the present invention.
  • FIGS. 4A and 4B illustrate exponent maps for dynamically allocating the number of bits of additional mantissa information to each sample in a frame depending on the magnitude of an input sample according to an embodiment of the present invention.
  • the exponent map is a matrix in which row indices are exponent indices of additional mantissa information derived from an exponent value of each sample and column indices are sample indices representing each sample. For example, when 0 to 3-bits for additional mantissa information are allocated to each sample in a frame of 40 samples, the exponent map is a 10 x 40 matrix.
  • exponent indices of each sample are proportional to the exponent value of each sample, are sequential, and the number of the exponent indices are the same as the number of bits of additional mantissa information. That is, exponent indices are obtained by incrementing the exponent value of each sample. For example, when the exponent value of a sample is "000" in binary, exponent indices corresponding to the sample are 0 (the exponent value + 0), 1 (the exponent value + 1), and 2 (the exponent value + 2). As another example, when the exponent value is 7 ("111" in binary), exponent indices are 7 (the exponent value + 0), 8 (the exponent value + 1), and 9 (the exponent value + 2). Accordingly, exponent indices of each sample for additional exponent information can range from 0 to 9.
  • the exponent map is established.
  • a bit allocation table indicating the number of additional bits allocated to each sample is created based on the exponent map. That is, 1 bit is allocated to each sample corresponding to the current exponent index which starts from the maximum value (i.e., 9) while decreasing by 1.
  • the bit allocation is performed until the total number of bits allocated to the samples is equal to the available bits in a frame. The generation of the bit allocation table will be explained in detail later with reference to FIG. 5 .
  • an exponent map is a matrix in which row indices are exponent indices of additional mantissa information derived from the exponent value of each sample and column indices are order indices indicating the number of samples with the same exponent index.
  • Each of elements of the exponent map represents a sample index with an exponent index.
  • the exponent map would be a 10 x 40 matrix since all of samples in a frame can have the common exponent index.
  • the current numbers of the samples with the exponent indices are increased by 1, respectively.
  • the corresponding exponent indices are 6, 7, and 8.
  • Elements corresponding to the exponent indices 6, 7, and 8, i.e., (6,0), (7,0), (8,0) are set to sample index 0, and the current numbers of samples with the exponent indices 6, 7, and 8 are set to 1, respectively.
  • the corresponding exponent indices are 4, 5, and 6.
  • Elements corresponding to the exponent indices 4, 5, and 6, i.e., (4,0), (5,0), (6,1) are set to sample index 1.
  • the reason why the (6,1)-th element is set to 1 is that the number of samples having the exponent index of 6 is already 1 in the previous sample. Accordingly, the numbers of the samples corresponding to the exponent indices 4, 5, 6, 7, and 8 are 1, 1, 2, 1, and 1, respectively. When the exponent map is completely generated in this way for all samples, the number of samples and sample indices corresponding to each exponent index can be obtained.
  • FIG. 5 is a flowchart illustrating a method of generating a bit allocation table according to an embodiment of the present invention.
  • an enhancement layer encoder outputs additional mantissa information to each sample based on an exponent value of each sample.
  • the enhancement layer encoder initializes all elements of a bit allocation table to 0, sets current available bits to the total number of available bits in a current frame, and sets a maximum value of the exponent indices as a current exponent index.
  • the enhancement layer encoder calculates the number of samples corresponding to each exponent index, by referring to the exponent maps illustrated in FIGS. 4A and 4B . For example, there are two samples, whose sample indices are 0 and 39, corresponding to an exponent index 8 in the exponential map illustrated in FIG. 4A .
  • the enhancement layer encoder compares the number of samples corresponding to the current exponent index with current available bits, and then sets the smaller one of the two numbers as the number of usable bits. In operation S530, 1 bit is allocated to each sample corresponding to the current exponent index until the number of the usable bits is exhausted. In operation S540, the enhancement layer encoder sets a value subtracting the number of the usable bits from the current available bits as a new number of current available bits.
  • operation S550 it is checked whether the current available bits are 0. If the current available bits are 0, the generation of a bit allocation table ends for the frame. If the current available bits are not 0, the enhancement layer proceeds to operation S560. In operation S560, the enhancement layer encoder updates the current exponent index by decrementing the current exponent index by 1, and returns to operation S520. Then the enhancement layer encoder repeats operations from S520 to S550.
  • FIG. 6 is a block diagram of an enhancement layer encoder according to an embodiment of the present invention.
  • the enhancement layer encoder includes an exponent map generating unit 600, a bit allocation table generating unit 610, and a bit output unit 620.
  • the enhancement layer encoder corresponds to an enhancement layer encoding unit 115 illustrated in FIG. 1 .
  • the exponent map generating unit 600 computes exponent indices of additional mantissa information per sample based on the exponent value of each sample, and then generates an exponent map including the exponent indices of each sample.
  • the exponent value of each sample can be extracted from the G.711 encoding unit 110 illustrated in FIG. 1 . Since the exponent map is illustrated in FIG. 4A and 4B , a detailed explanation thereof will not be given here.
  • the bit allocation table generating unit 610 retrieves samples corresponding to each exponent index and allocates 1 bit to the retrieved samples by sequentially decrementing the exponent index by 1 from the maximum value. When this bit allocation procedure is completed for all of exponent indices, the bit allocation table generating unit 610 generates a bit allocation table containing the number of bits allocated to each sample. A method of generating the bit allocation table is illustrated in FIG. 5 .
  • the bit output unit 620 outputs the most significant bits of the additional mantissa information in amount of the number of the bits allocated to each sample in an input frame by using the bit allocation table. That is, the bit output unit 620 outputs [the additional mantissa information] / (2 ⁇ [the number of the bits of the additional mantissa information - the allocated number of the bits]).
  • FIG. 7 is a block diagram of an enhancement layer decoder according to an embodiment of the present invention.
  • the enhancement layer decoder includes an exponent map generating unit 700, a bit allocation table generating unit 710, and an additional mantissa decoding unit 720.
  • the exponent map generating unit 700 and the bit allocation table generating unit 710 are the same as the exponent map generating unit 600 and the bit allocation table generating unit 610 illustrated in FIG. 6 , and thus a detailed explanation thereof will not be given here.
  • the additional mantissa decoding unit 720 extracts and decodes additional mantissa information of each sample from an enhancement bitstream based on the number of bits of the additional mantissa information allocated to each sample.
  • FIG. 8 is a block diagram of an enhancement layer encoder according to another embodiment of the present invention.
  • the enhancement layer encoder includes an additional mantissa extracting unit 800, a bit allocating unit 810, and a bit output unit 820.
  • the additional mantissa extracting unit 800 extracts additional mantissa information from an input frame based on an exponent value obtained from the G.711 encoding performed on the input frame. That is, the additional mantissa extracting unit 800 extracts some bits followed by mantissa information (i.e., G.711 mantissa information of 4 bits) as additional mantissa information, based on the exponent value obtained from the G.711 encoding performed on the input frame. Although all of bits followed by the mantissa information may be the additional mantissa information, it is assumed in FIG. 8 that the maximum number of bits of the additional mantissa information is 3 in the current embodiment.
  • an input sample is "0000 0001 1010 1001" in binary.
  • the input sample is encoded in G.711 A-law, which is a combination of a sign bit of "1", exponent bits of "001”, and mantissa bits of "1010".
  • the resulting additional mantissa information is "100", assuming that the maximum number of bits of additional mantissa information is 3.
  • the bit allocating unit 810 calculates the number of bits allocated to each sample by using the total number of available bits and exponent values of each sample. For example, if the bit-rate of an enhancement layer is 16 Kbit/s and the frame size is 5 ms, the total number of available bits per frame is 80 bits.
  • the bit allocating unit 810 dynamically computes the number of bits for additional mantissa information per each sample based on the priorities of the additional mantissa information of each sample with criterion to minimize quantization error in each frame. For example, the priority may be determined from the exponent value of each sample which means a quantization step in a G.711 codec.
  • the bit output unit 820 outputs the additional mantissa information in amount of the number of the bits allocated to each sample computed by the bit allocating unit 810.
  • bit output unit 820 outputs "10" as its encoded enhancement bitstream.
  • the maximum number of bits per sample for additional mantissa information is extracted from the sample, and then is truncated to allocated number of bits for the sample.
  • the allocated number of bits is extracted from a sample after a bit allocation table is established, in another embodiment.
  • FIG. 9 is a flowchart illustrating a method of an enhancement layer encoding according to an embodiment of the present invention.
  • an enhancement layer encoder extracts additional mantissa information based on an exponent value obtained from the G.711 encoding performed on the input frame.
  • the additional mantissa information may be the whole remaining bits followed by mantissa information in the input frame, it is assumed in FIG. 9 that the maximum number of bits for the additional mantissa information is 3 in the current embodiment. Accordingly, the enhancement layer encoder extracts additional mantissa information of 3 bits only.
  • the enhancement layer encoder computes the number of additional bits for mantissa information per sample by using the exponent value obtained from the G.711 encoding.
  • the enhancement layer encoder sets priorities for 3 respective bits of the additional mantissa information of each sample as being proportional to the exponent value of each sample. For example, an exponent index may be used as a priority as shown in FIGS. 4A and 4B .
  • the enhancement layer encoder sequentially allocates 1 bit to samples with from the highest priority to the lowest priority until a total number of allocated bits exceeds a total number of available bits in the frame.
  • the enhancement layer encoder outputs the most significant bits of the additional mantissa information in amount of the number of the bits allocated to each sample in an input frame.
  • FIG. 10 is a block diagram of an enhancement layer decoder according to another embodiment of the present invention.
  • the enhancement layer decoder includes a decoder bit allocating unit 1000, an additional mantissa decoding unit 1010, and an enhancement signal synthesizing unit 1020.
  • the decoder bit allocating unit 1000 obtains the number of bits for additional mantissa information per sample by using the total number of available bits in a frame and exponent values obtained by G.711 decoding.
  • the operation of the decoder bit allocating unit 1000 is the same as that of the bit allocating unit illustrated in FIG. 7 , and thus a detailed explanation thereof will not be given here.
  • the additional mantissa decoding unit 1010 restores additional mantissa information from an enhancement bitstream, using the exponent value and the number of the bits for the additional mantissa information obtained by the decoder bit allocating unit 1000. That is, the additional mantissa decoding unit 1010 restores the additional mantissa information by extracting the same number of bits as the number of the bits of the additional mantissa information allocated to each sample from the enhancement bitstream.
  • the maximum number of the bits for the additional mantissa information is 3
  • a pseudo-code for operating the additional mantissa decoding unit 1010 is shown below.
  • the additional mantissa decoding unit 1010 inserts a bit string of "0"s to the decoded additional mantissa information in amount of difference between the maximum number of bits for the additional mantissa information and the number of allocated bits for the additional mantissa information.
  • the enhancement signal synthesizing unit 1020 restores an enhancement signal by using the restored additional mantissa information, exponent value and sign information obtained by G.711 decoding.
  • a pseudo-code for operating the enhancement signal synthesizing unit 1020 is as follows. At first, the restored additional mantissa information is bit-shifted to left in amount of the exponent value, and then sign information is added in the way that if the sign information indicates a negative value, the bit-shifted additional mantissa information is multiplied by (-1), and otherwise, the bit-shifted additional mantissa information itself is an enhancement sample.
  • FIG. 11 is a flowchart illustrating a method of decoding an enhancement layer according to an embodiment of the present invention.
  • an enhancement layer decoder obtains the number of additional bits allocated to each sample by using the maximum number of available bits and exponent values in a frame obtained by a G.711 decoding unit.
  • the enhancement layer decoder extracts additional mantissa information, as many as the number of the additional bits allocated to each sample, from an enhancement bitstream.
  • the enhancement layer decoder restores additional mantissa information.
  • the present invention may be embodied as computer-readable codes on a computer-readable recording medium.
  • the computer-readable recording medium is any data storage device that can store data which can be thereafter read by a computer system. Examples of the computer-readable recording medium include read-only memories (ROMs), random-access memories (RAMs), CD-ROMs, magnetic tapes, floppy disks, and optical data storage devices.
  • ROMs read-only memories
  • RAMs random-access memories

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Claims (14)

  1. Procédé de codage d'une couche d'amélioration afin de réduire une erreur de quantification dans un codec G.711, ledit procédé comprenant :
    la génération d'une carte d'exposant qui est une matrice, comprenant : des indices d'exposant d'informations de mantisse supplémentaires dérivées d'une valeur d'exposant de chaque échantillon, et des indices d'échantillons pour chaque échantillon d'une trame ;
    la génération d'une table d'attribution de bits contenant le nombre de bits attribués à chaque échantillon en référence à ladite carte d'exposant, sous la forme de la répétition d'un processus d'attribution de 1 bit à chaque échantillon, avec un indice d'exposant respectif qui part d'une valeur maximale tout en diminuant de 1 à chaque répétition, jusqu'à ce que le nombre total de bits attribués aux échantillons soit égal au nombre total de bits disponibles au sein de la trame ; et
    la remise d'un ou plusieurs bits les plus significatifs, autant que le nombre de bits attribués à chaque échantillon, à partir desdites informations de mantisse supplémentaires de chaque échantillon, en référence à ladite table d'attribution de bits.
  2. Procédé selon la revendication 1, dans lequel la génération d'une carte d'exposant comprend la définition de valeurs, qui sont proportionnelles à la valeur d'exposant de chaque échantillon et sont aussi nombreuses que le nombre de bits pour lesdites informations de mantisse supplémentaires, sous la forme d'indices d'exposant desdites informations de mantisse supplémentaires de chaque échantillon.
  3. Procédé selon la revendication 2, dans lequel la génération d'une carte d'exposant comprend la définition d'indices d'exposant desdites informations de mantisse supplémentaires selon des valeurs augmentées de 1, en partant de la valeur d'exposant d'un échantillon.
  4. Procédé selon la revendication 1, dans lequel la répétition du processus comprend :
    la définition de la valeur maximale des indices d'exposant en tant qu'indice d'exposant actuel ;
    la comparaison du nombre d'échantillons ayant ledit indice d'exposant actuel avec le nombre de bits disponibles dans la trame, et la définition du nombre de bits utilisables selon le plus faible des deux nombres ;
    l'attribution séquentielle de 1 bit à chaque échantillon ayant ledit indice d'exposant actuel, dans les limites du nombre de bits utilisables ;
    la mise à jour du nombre de bits disponibles selon la valeur obtenue en soustrayant le nombre de bits utilisables du nombre de bits disponibles ;
    le fait de vérifier si le nombre mis à jour de bits disponibles est de zéro ou non ; et
    si le nombre mis à jour de bits disponibles n'est pas nul, la diminution de l'indice d'exposant actuel de 1, et le retour à l'étape de définition du nombre de bits utilisables.
  5. Procédé selon la revendication 1, dans lequel le nombre de bits desdites informations de mantisse supplémentaires est de 3.
  6. Procédé selon la revendication 1, dans lequel les informations d'exposant sont obtenues par un codage G.711.
  7. Codeur de couche d'amélioration (115) destiné à un codec G.711 qui comprend :
    une unité de génération de carte d'exposant (600) destinée à générer une carte d'exposant qui est une matrice, comprenant : des indices d'exposant d'informations de mantisse supplémentaires dérivées de la valeur d'exposant de chaque échantillon, et des indices d'échantillons pour chaque échantillon d'une trame ;
    une unité de génération de table d'attribution de bits (610) destinée à générer une table d'attribution de bits qui contient le nombre de bits attribués à chaque échantillon en référence à ladite carte d'exposant, sous la forme de la répétition d'un processus d'attribution de 1 bit à chaque échantillon, avec un indice d'exposant respectif qui part d'une valeur maximale tout en diminuant de 1 à chaque répétition, jusqu'à ce que le nombre total de bits attribués aux échantillons soit égal au nombre total de bits disponibles au sein de la trame ; et
    une unité de remise de bits (620) destinée à remettre un ou plusieurs bits les plus significatifs, autant que le nombre de bits attribués à chaque échantillon, à partir desdites informations de mantisse supplémentaires de chaque échantillon, en référence à ladite table d'attribution de bits.
  8. Codeur de couche d'amélioration selon la revendication 7, dans lequel ladite unité de génération de carte d'exposant définit des valeurs, qui sont proportionnelles à la valeur d'exposant de chaque échantillon et sont aussi nombreuses que le nombre de bits pour lesdites informations de mantisse supplémentaires, sous la forme d'indices d'exposant desdites informations de mantisse supplémentaires.
  9. Codeur de couche d'amélioration selon la revendication 8, dans lequel ladite unité de génération de carte d'exposant définit les indices d'exposant desdites informations de mantisse supplémentaires selon des valeurs augmentées de 1, en partant de la valeur d'exposant.
  10. Codeur de couche d'amélioration selon la revendication 7, dans lequel, si une différence entre le nombre total de bits disponibles au sein de la trame et le nombre total de bits attribués aux échantillons est inférieur au nombre d'échantillons ayant un indice d'exposant actuel, ladite unité de génération de table d'attribution de bits attribue 1 bit à chaque échantillon ayant l'indice d'exposant actuel, respectivement, jusqu'à ce que la différence de nombre de bits n'existe plus.
  11. Codeur de couche d'amélioration selon la revendication 7, dans lequel ladite unité de remise de bits remet [les informations de mantisse supplémentaires de chacun des échantillons] /2^ [le nombre de bits pour lesdites informations de mantisse supplémentaires - le nombre de bits attribués à chaque échantillon].
  12. Codeur de couche d'amélioration selon la revendication 7, dans lequel lesdites informations de mantisse supplémentaires comprennent 3 bits.
  13. Codeur de couche d'amélioration selon la revendication 7, dans lequel la valeur d'exposant est obtenue par un codage G.711.
  14. Codeur (100) destiné à un codec G.711 comprenant:
    une unité de codage G.711 (110) destinée à coder une trame d'entrée ;
    une unité de codage de couche d'amélioration selon l'une des revendications 7 à 13, destinée à coder ladite trame d'entrée en attribuant dynamiquement le nombre de bits pour les informations de mantisse supplémentaires à chaque échantillon de ladite trame d'entrée, sur la base d'une information d'exposant de chaque échantillon, qui est obtenue à partir de ladite unité de codage G.711 ; et
    une unité de multiplexage destinée à multiplexer un flux binaire de ladite unité de codage G.711 et un flux binaire de ladite unité de codage de couche d'amélioration.
EP08793289A 2007-08-16 2008-08-18 Appareil et procédé de codage de couche d'amélioration Active EP2179415B1 (fr)

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EP10153693.6A EP2187387B1 (fr) 2007-08-16 2008-08-18 Procédé de codage et décodage de couche à enrichissement
EP10153630A EP2202728B1 (fr) 2007-08-16 2008-08-18 Appareil et procédé de décodage de couche à enrichissement

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KR1020080024919A KR100912826B1 (ko) 2007-08-16 2008-03-18 Ｇ．７１１ 코덱의 음질 향상을 위한 향상 계층 부호화 및복호화 장치와 그 방법
KR1020080079929A KR100912827B1 (ko) 2007-08-16 2008-08-14 Ｇ．７１１ 코덱의 음질 향상을 위한 향상 계층 부호화 및 복호화 장치와 그 방법
PCT/KR2008/004775 WO2009022884A1 (fr) 2007-08-16 2008-08-18 Appareil et procédé de codage et de décodage de couche d'amélioration

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EP2179415A4 EP2179415A4 (fr) 2011-07-20
EP2179415B1 true EP2179415B1 (fr) 2013-03-20

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EP08793289A Active EP2179415B1 (fr) 2007-08-16 2008-08-18 Appareil et procédé de codage de couche d'amélioration
EP10153630A Active EP2202728B1 (fr) 2007-08-16 2008-08-18 Appareil et procédé de décodage de couche à enrichissement

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CN102959619B (zh) * 2010-06-29 2014-06-11 日本电信电话株式会社 比特分配装置、方法
FR2981781A1 (fr) * 2011-10-19 2013-04-26 France Telecom Codage hierarchique perfectionne

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US6785261B1 (en) * 1999-05-28 2004-08-31 3Com Corporation Method and system for forward error correction with different frame sizes
US6724814B1 (en) * 1999-06-24 2004-04-20 Intel Corporation Pad and CODEC detection
US6650762B2 (en) * 2001-05-31 2003-11-18 Southern Methodist University Types-based, lossy data embedding

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EP2179415A1 (fr) 2010-04-28
EP2202728A1 (fr) 2010-06-30
WO2009022884A1 (fr) 2009-02-19
EP2187387A3 (fr) 2012-01-25
EP2187387A2 (fr) 2010-05-19
EP2179415A4 (fr) 2011-07-20
EP2202728B1 (fr) 2013-03-27

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