Encoding device, decoding device, system and method for encoding and decoding

Abstract

To provide an apparatus and method for optimal residual quantization in source coding, and a source coding scheme for encoding a quantized signal with a predetermined number of bits.SOLUTION: In an encoding device 100, a quantization stage quantizes an input signal using a dead zone to obtain a plurality of quantized values. The entropy encoder encodes the plurality of quantized values using an entropy encoding scheme to obtain a plurality of entropy encoded values. The residual quantization stage quantizes a residual signal resulting from the quantization stage and determines at least one quantized residual value depending on a dead-zone of the quantization stage. An encoded signal former forms an encoded signal from the plurality of entropy encoded values and the at least one quantized residual value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Some embodiments relate to an apparatus and method for optimal residual quantization in source coding, and some embodiments relate to a source coding scheme for encoding a quantized signal with a predetermined number of bits. [Background technology]

[0002] Entropy coding is an efficient tool for exploiting redundancy in transmitted symbols. It is usually used in transform-based coding after quantization of spectral lines. By utilizing a priori probability distributions, the quantized values ​​can be losslessly coded using a reduced number of bits. Its principle consists in generating codewords whose length is a function of the symbol probabilities.

[0003] The bit consumption is usually known only after writing the entropy-coded symbols into the bitstream. It usually becomes an issue when optimizing the quantization stage, which needs to know the bit consumption in order to optimize the rate-distortion function. It becomes even more of an issue when the bitstream needs to have a constant size per frame, known as a constant bitrate, which is a requirement of most communication network protocols.

[0004] In transform coders, a set of scale factors typically defines the quantization by shaping the quantization noise in the frequency domain. The noise shaping is a function of both the perceptual distortion, usually given by a psychoacoustic model, and the resulting bit consumption. However, the latter factor is usually known after the quantization noise shaping is determined. An optimization loop can be used to converge the optimization. However, such optimization is relatively complex, and the number of iterations must be strongly limited in practical applications. Furthermore, to further reduce computational complexity, the bit consumption is usually only estimated rather than fully calculated. If the final bit consumption is underestimated, the bitstream must be truncated, which is usually avoided in most cases. In fact, underestimation would result in a strong truncation of the bitstream, which is equivalent to saturating the quantization. Therefore, quantization optimization is usually designed to overestimate the bit consumption. As a result, some bits often remain unused in the final bitstream.

[0005] To solve this problem, a residual (or second) quantization stage can be added after the first quantization stage to utilize any unused bits that may occur. These remaining bits can then be used to refine the quantization noise. The principle behind this is explained below.

[0006] 10 shows a block diagram of a transform coder 10. The transform coder 10 includes a first quantization stage 12, a residual quantization stage 14, an entropy coder 16, an entropy coded bit estimation unit 18, a multiplexer 20 and a transform unit 22.

[0007] The transform unit 22 is configured to transform the input signal from the time domain to the frequency domain. The first quantization stage 12 is configured to quantize the input signal in the frequency domain into a plurality of quantized spectral values ​​q. The plurality of quantized spectral values ​​q, the input signal x in the frequency domain, and the remaining number of bits are input to a residual (or second) quantization stage 14, which refines the output of the first quantization stage 12 to generate a plurality of quantized residual values ​​q. r The entropy encoder 16 is configured to entropy encode the plurality of quantized spectral values ​​q to obtain a plurality of entropy-coded values ​​e. The multiplexer 20 is configured to multiplex the plurality of entropy-coded values ​​e, a scale factor dependent on the information provided by the first quantization stage 14, and a plurality of quantized residual values ​​provided by the second quantization stage 16 to obtain a bitstream.

[0008] The transform coder 10 shown in FIG. 10 is designed to provide a target number of bits per frame. Quantization may be adjusted to reach this target value; however, for complexity reasons, only an estimate of the entropy coder bit consumption is made when adjusting the quantization step. Furthermore, even if the bit estimate is very accurate, it may be impossible to find a set of scale factors that yields the expected target bit consumption. After the first quantization stage 12, the quantized value q is entropy coded. The remaining unused bits are then allocated to residual quantization, which refines the output of the first quantization stage 12. Residual quantization stage 14 receives as input the quantized spectral value q, the original spectral value x, and the number of remaining bits. The number of remaining bits may be an estimate of the remaining bits or the true number. Estimation is typically used when local synthesis is required on the coder side to make switching decisions in a closed-loop decision scheme, such as that implemented in AMR-WB+ (Adaptive Multi-Rate Wideband Extension). In this case, residual coding must be invoked before entropy coder 16 is invoked if necessary.

[0009] In a typical transform coder 10, the residual quantization stage 14 performs a simple uniform scalar quantization of the difference between the original input signal and the dequantized input signal, obtained by dequantizing the quantized spectral values. However, through rate-distortion performance analysis, it is known that uniform quantization is only optimal for memoryless and uniformly distributed sources.

[0010] It is therefore an object of the present invention to provide an improved residual quantization for non-memoryless and non-uniformly distributed sources.

[0011] This object is solved by the independent claims.

[0012] An embodiment of the present invention provides an encoding device including a quantization stage, an entropy encoder, a residual quantization stage, and an encoded signal generator. The quantization stage is configured to quantize an input signal using a dead zone to obtain a plurality of quantized values. The entropy encoder is configured to encode the plurality of quantized values ​​using an entropy coding scheme to obtain a plurality of entropy-coded values. The residual quantization stage is configured to quantize a residual signal resulting from the quantization stage and determine at least one quantized residual value depending on the dead zone of the quantization stage. The encoded signal generator is configured to generate an encoded signal from the plurality of entropy-coded values ​​and the at least one quantized residual value.

[0013] Furthermore, an embodiment of the present invention provides a decoding device including a coded signal analyzer, an entropy decoder, and an inverse quantization stage. The coded signal analyzer is configured to analyze the coded signal to obtain a plurality of entropy-coded values ​​and at least one quantized residual value. The entropy decoder is configured to decode the plurality of entropy-coded values ​​using an entropy decoding scheme to obtain a plurality of quantized values. The inverse quantization stage is configured to inverse quantize the plurality of quantized values ​​to obtain an output signal. Furthermore, the inverse quantization stage is configured to refine the inverse quantization levels used to obtain the output signal depending on the quantized residual value and a dead zone.

[0014] According to the inventive concept, the error between the (original) input signal and the dequantized signal obtained by dequantizing a plurality of quantized values ​​can be reduced or optimized by a residual quantization stage on the encoder side, which takes into account the dead zone used to quantize the input signal, and can be reduced or optimized by a dequantization stage on the decoder side, which takes into account this dead zone when refining the dequantization levels used to obtain the dequantized signal (called the output signal).

[0015] Furthermore, an embodiment of the present invention provides an encoding method, the method comprising: a quantizing step of quantizing an input signal and obtaining a plurality of quantized values ​​using a dead-zone, an encoding step of encoding the plurality of quantized values ​​using an entropy coding scheme and obtaining a plurality of entropy-coded values, a quantizing step of a residual signal resulting from the quantization by the quantization stage and determining a plurality of quantized residual values ​​depending on the dead-zone of the quantization stage, and a forming a bitstream from the plurality of entropy-coded values ​​and the plurality of quantized residual values.

[0016] Furthermore, an embodiment of the present invention provides a decoding method, which includes the steps of: analyzing an encoded signal to obtain a plurality of entropy-coded values ​​and one quantized residual value; decoding the plurality of entropy-coded values ​​using an entropy decoding scheme to obtain a plurality of quantized values; dequantizing the plurality of quantized values ​​to obtain an output signal; and refining the dequantization level used to obtain the output signal depending on a dead zone and the quantized residual value.

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 2 is a block diagram of an encoder according to an embodiment of the present invention; [Figure 2] FIG. 2 is a block diagram of a decoder according to one embodiment of the present invention; [Figure 3] 1 is a block diagram of a system according to an embodiment of the present invention. [Figure 4] FIG. 2 is a block diagram of a residual quantization stage according to one embodiment of the present invention; [Figure 5] FIG. 1 illustrates the inverse quantization levels and quantization thresholds used in a dead-zone uniform threshold scalar quantization scheme. [Figure 6]FIG. 10 illustrates two refined inverse quantization levels for non-zero quantized values. [Figure 7] FIG. 10 illustrates three refined inverse quantization levels for a zero quantized value. [Figure 8] 1 is a flowchart of an encoding method according to an embodiment of the present invention. [Figure 9] 3 is a flowchart of a decoding method according to an embodiment of the present invention. [Figure 10] FIG. 1 is a block diagram of a conventional transform coder using residual quantization.

[0019] Identical or equivalent components or structures having identical or equivalent functions are given identical or equivalent reference numerals in the following description.

[0020] In the following description, numerous details are presented to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures or devices are described in block diagram form rather than in detail to avoid obscuring embodiments of the present invention. In addition, features of different embodiments described below may be combined with each other unless otherwise stated.

[0021] Because entropy coding provides codewords of various lengths, it is difficult to predict the exact bit consumption before writing them to the bitstream. However, bit consumption is necessary to optimize quantization. In most cases, and for complexity reasons, quantization is suboptimal and some minority bits are still unused. Residual quantization is a second layer of quantization that utilizes these unused bits to refine the quantization error.

[0022] The embodiments of the present invention described below provide an encoder, decoder and method that optimizes this residual quantization.

[0023] FIG. 1 shows a block diagram of an encoder 100 according to one embodiment of the present invention. The encoder 100 includes a quantization stage 102 (e.g., a first quantization stage), an entropy encoder 104, a residual quantization stage 106 (e.g., a second quantization stage), and an encoded signal generator 108. The quantization stage 102 is configured to quantize an input signal 140 using a dead zone to obtain a plurality of quantized values ​​142(q). The entropy encoder 104 is configured to encode the plurality of quantized values ​​142(q) using an entropy coding scheme to obtain a plurality of entropy-coded values ​​144(e). The residual quantization stage 106 is configured to quantize a residual signal resulting from the quantization in the quantization stage 102, and generates at least one quantized residual value 146(q) depending on the dead zone of the quantization stage 102. r The coded signal forming unit 108 is configured to determine a plurality of entropy coded values ​​144(e) and at least one quantized residual value 146(q r ) to form an encoded signal 148.

[0024] The idea of ​​the present invention is to reduce or optimize the error between an (original) input signal and a dequantized version of the quantized version of that input signal by using a residual quantization stage on the encoding side that takes into account the dead zone that was used to quantize the input signal, and a dequantization stage on the decoder side that also takes into account that dead zone when refining the dequantization levels used to obtain the dequantized signal.

[0025] In an embodiment, the quantization stage 102 may be configured to perform dead-zone uniform threshold scalar quantization (DZ-UTSQ).

[0026] In an embodiment, the coded signal former 108 may be configured to form the coded signal 148 by appending at least one quantized residual value 146 or multiple quantized residual values ​​146 to multiple entropy coded values ​​144 until the coded signal 148 has the maximum length available for transmission to a decoder. It is not limited that the bitstream may contain other information, such as scaling factors defining the first quantization stage noise shaping, or prediction coefficients used to shape the quantization noise and used in post-filtering of the output signal in the time domain.

[0027] For example, the coded signal former 108 may be configured to provide a bitstream as the coded signal 148. Thus, the coded signal former 108, e.g., a multiplexer, may be configured to append at least one quantized residual value 146 or a plurality of quantized residual values ​​146 to one end of the bitstream. The bitstream generated by the encoder 100 may be transferred (e.g., transmitted or broadcast) to a decoder, or may be stored, e.g., in a non-volatile storage medium, for later decoding by the decoder. Thus, the bitstream may be transmitted or stored using data frames or data packets, where the bitstream may need to have a certain size (also referred to herein as target bits) per data frame or data packet.

[0028] To obtain a bitstream of a constant size or with a predetermined target number of bits, the coded signal former 108 may be configured to append quantized residual values ​​146 to the entropy coded values ​​144 until the bitstream reaches the predetermined target number of bits. The residual quantization stage 106 may stop determining quantized residual values ​​146 when the bitstream has the predetermined target length or the predetermined target number of bits.

[0029] In an embodiment, the input signal 140 may be a frequency domain input signal 140. The encoder 100 may include a transform unit configured to transform the time domain input signal into the frequency domain input signal 140.

[0030] 2 shows a block diagram of a decoder 120 according to one embodiment of the present invention. The decoder 120 includes a coded signal parser 122, an entropy decoder 124, and an inverse quantization stage 126. The coded signal parser 122 is configured to analyze a coded signal 148 to obtain a plurality of entropy-coded values ​​144(e) and at least one quantized residual value 146(qr). The entropy decoder 124 is configured to decode the plurality of entropy-coded values ​​144(e) using an entropy decoding scheme to obtain a plurality of quantized values ​​142(q). The inverse quantization stage 126 is configured to inverse quantize the plurality of quantized values ​​142(q) to obtain an output signal 150. Thus, the inverse quantization stage 126 is configured to refine the inverse quantization levels used to obtain the output signal 150 depending on the quantized residual values ​​146(qr) and the dead zone used in the quantization stage 106 to obtain the multiple quantized values ​​142(q) in the encoder 100.

[0031] In an embodiment, the inverse quantization stage 126 may be configured to refine the inverse quantization levels by determining the refined inverse quantization levels in dependence on the dead zone.

[0032] For example, the inverse quantization stage 126 may be configured to determine, depending on the dead zone, more precisely, depending on the width of the dead zone, the level at which the inverse quantization level should be refined, i.e., increased or decreased, to obtain refined inverse quantization levels. Furthermore, the inverse quantization stage 126 may be configured to determine at least two new inverse quantization levels depending on the dead zone, and to use one of these at least two refined inverse quantization levels indicated by the quantized residual value 146 to obtain the output signal 150. In other words, the quantized residual value 146 indicates which of the at least two refined inverse quantization levels should be used to obtain the output signal 150.

[0033] 3 shows a block diagram of a system 130 according to one embodiment of the present invention, which includes the encoder 100 shown in FIG. 1 and the decoder 120 shown in FIG.

[0034] The features of the encoder 100 and decoder 120 and the interactions or interactions of the features of the encoder 100 and decoder 120 are described in more detail below.

[0035] 4 shows a block diagram of the residual quantization stage 106 according to one embodiment. The residual quantization stage 106 includes a residual quantizer 106′, an inverse quantizer 160, and a comparator 162. The inverse quantizer 160 may be configured to inverse quantize the quantized values ​​142(q) provided by the quantization stage 102 to obtain an inverse quantized input signal 152(x_q). The comparator 162 may be configured to compare the input signal 140(x) with the inverse quantized input signal 152(x_q) to obtain a residual signal 154. The residual quantizer 106′ may be configured to quantize the residual signal generated by the quantization stage 102.

[0036] In other words, the residual quantization block diagram is shown in Figure 4. The spectrum 142(q) is dequantized and compared with the original spectrum 140(x). A second layer of quantization is then performed depending on the remaining available bits. The second quantization step performed by the residual quantization stage 106 is typically a greedy quantization, i.e., the quantization is performed line by line, and each requantized value is determined independently from the subsequently transmitted information. In this way, whenever the bitstream 148 provided by the coded signal former 108 reaches the desired size, the residual quantized bitstream 146(q r ) may be truncated.

[0037] 4, the residual quantization stage 106 may further include a control unit 164, ie, an adjuster. The control unit 164 may be configured to control or optimize the residual quantization stage 106'.

[0038] For example, the control unit 164 may be configured to control the residual quantizer 106′ such that the residual quantizer 106′ quantizes the residual signal 154 depending on a dead zone, more precisely, depending on the width of the dead zone used in the quantization stage 102 to obtain a plurality of quantized values ​​142(q). Furthermore, the control unit 164 may be configured to control the residual quantizer 106′ depending on a target number of bits and a number of consumed bits (e.g., the number of bits consumed by the entropy-coded values ​​144 provided by the entropy coder, or the number of bits consumed by the entropy-coded values ​​144 and the quantized residual values ​​already provided by the residual quantizer 106′). Furthermore, the control unit 164 may be configured to control the residual quantizer 106′ depending on information provided by the inverse quantizer 160. The information provided by the inverse quantization unit 160 may include the width of the dead zone, which may be fixed or adaptively modified, and may further include the scaling factor applied in the first quantization stage to normalize the spectrum and define the quantization step, and may also include an indication of whether the quantized value was zero.

[0039] In conventional residual quantization, Qr performed by the residual quantization stage is a simple uniform scalar quantization of the difference x[i]-x_q[i]. If x[i]>x_q[i] Qr[i]=(int)(0.5+(x[i]-x_q[i]) / delta_r) Other cases Qr[i]=(int)(-0.5+(x[i]-x_q[i]) / delta_r) where x[i] is the input signal 140, x_Q[i] is the dequantized input signal 152, (int) is the integer rounding function, and delta_r is the quantization step of the residual quantizer Qr, which is typically smaller than the quantization step delta used in the first quantizer Q. In general: delta_r=0.5*delta

[0040] Embodiments of the present invention solve two problems related to residual quantization. The first main problem is how to obtain an optimal Qr (a function of the residual quantization stage 106) knowing the first quantization stage 102. The second problem is how to minimize the mismatch between the encoder's local synthesis and the decoder's synthesis when the number of remaining bits is to be estimated.

[0041] Through rate-distortion performance analysis, it is known that uniform quantization (used in traditional residual quantization) is optimal only for memoryless and uniformly distributed sources. If entropy coding is subsequently used, uniform quantization becomes suboptimal for Gaussian sources and at very high bit rates. At low rates, a near-optimal solution is to use uniform threshold scalar quantization (DZ-UTSQ) with a deadzone. This family of quantizers is suboptimal for a wide range of distributions, such as Gaussian, Laplacian, and generalized Laplacian. The deadzone factor can be optimized in various ways. The factor can be optimized in real time based on an estimate of the distribution. Briefly, the factor can be fixed to a default optimal value found for the expected input signal, or it can be adapted depending on some measure reflecting the distribution, such as spectral tonality.

[0042] In the following we describe a solution that optimizes the residual quantization Qr performed by the residual quantization stage 106 depending on the first stage DZ-UTSQ 102. The deadzone parameter is called dz and DZ-UTSQ 102 is defined as follows: If x[i]>0 Q[i]=(int)(rounding_dz+(x[i]) / delta) Other cases Q[i]=(int)(-rounding_dz+(x[i]) / delta) and x_q[i]=delta*Q[i] where x[i] is the input signal 140, x_Q[i] is the dequantized input signal 152, (int) is the integer rounding function, and delta is the quantization step used in the DZ-UTSQ 102; rounding_dz=1-dz / 2 is.

[0043] Figure 5 shows the DZ-UTSQ102 scheme, where the scale is normalized by delta. The deadzone is usually larger than the normalized cell size in step 1. A deadzone of 1.25 is a good estimate for most frequency-converted audio samples. The deadzone can be reduced if the signal is noisy or increased if the signal is more tonal.

[0044] An embodiment of the present invention defines an optimal quantization refinement of the error x[i]-x_q[i]. Because the residual coding is not entropy constrained, no additional dead zone is used in the residual quantization Qr. Furthermore, the distribution of the quantization error of the first quantization stage 102 is assumed to be uniform on the left and right sides of the quantization cell bounded by the reproduction level 170. This is a high-rate estimate, i.e., the size of the new quantization cell is assumed to be small enough to ignore the unevenly distributed error within the cell. This estimate is valid for most target bit rates.

[0045] There are two main cases here: when a sample is quantized with a non-zero value, and when it is quantized with a zero value.

[0046] For non-zero quantized values, one bit can be allocated for the residual quantization Qr per sample, defining two relative reproduction levels fac_m and fac_p. fac_p=0.5-rounding_dz*0.5=0.25*(dz) fac_m=0.5*rounding_dz=0.5*(1-0.5*dz)

[0047] Here, fac_p is a normalized absolute value and may indicate the value by which the normalized absolute value of the inverse quantization level (or reproduction level) 172 should be increased in order to obtain the first refined inverse quantization level 174 of the two refined inverse quantization levels 174 and 176, fac_m is a normalized absolute value and indicates the value by which the normalized absolute value of the inverse quantization level 172 should be decreased in order to obtain the second refined inverse quantization level 176 of the two refined inverse quantization levels 174 and 176, and dz is the normalized width of the dead zone, as is clear from FIG. 6.

[0048] 6 shows two relative (or refined) reproduction levels 174 and 176 for a 1-bit reproduction level 172. Using one additional bit, the reproduction level 172 can be refined using 1-fac_m (resulting in a second refined inverse quantization level 176) or 1+fac_p (resulting in a first refined inverse quantization level 174). The original cell is divided into two non-uniform cells. The residual quantization Qr is optimal in terms of RD performance, since the quantization error of Q (the quantization function of the first quantization stage 102) is considered to be uniformly distributed within the new cell. It should be noted that the quantization Q and the residual quantization Qr form one embedded quantization, i.e., the bits allocated to the residual quantization Qr can be discarded, and Q-1 can be performed.

[0049] The residual quantization Qr performed by the residual quantization stage 106 is summarized as follows: TIFF2026010118000002.tif21164 where prm is the bitstream generated by the residual quantization stage 106 using the quantized residual values, x[i] is the input signal, x_Q[i] is the inverse quantized input signal, n is an index that is incremented by 1 for each non-zero quantized value refined by Qr, and i is an index that is incremented by 1 for each obtained quantized value.

[0050] Then, the inverse Qr can be expressed as: TIFF2026010118000003.tif50159

[0051] Reverse Qr is N bits It can be seen that this is only done for the first bits of . This means that the encoder can generate more bits than the encoder or decoder will actually decode. This mechanism is used when the number of remaining bits is estimated and local combining on the encoder side is required. An assumed reconstructed signal is generated at the encoder. However, it is also possible that the decoder will be able to decode more or less bits depending on the true remaining available bits in the bitstream.

[0052] Alternatively, more than one bit per sample can be allocated to Qr. Using the same principle, the optimum playback level can be defined for Qr playback levels of power of two bits.

[0053] For zero quantized values, the residual quantization Qr can be allocated more than 1 bit because it is necessary to have zero as the playback level for perceptual reasons, which avoids creating artificially noisy signals, for example during quiet periods. A special three-level variable length code can be used. 0: code a zero 10: a negative reconstruction level 11: a positive reconstruction level

[0054] The new relative playback level fac_z is calculated as follows: fac_z= dz / 3

[0055] Here, fac_z is a normalized absolute value and may indicate the value by which the normalized absolute value of the inverse quantization level 172 should be increased to obtain the first refined inverse quantization level 174 of the two refined inverse quantization levels 174 and 176, or may indicate the value by which the normalized absolute value of the inverse quantization level 172 should be decreased to obtain the second refined inverse quantization level 176 of the two refined inverse quantization levels 174 and 176, and dz is the normalized width of the dead zone, as is clear from FIG. 7.

[0056] 7 shows the residual quantization Qr performed by the residual quantization stage 106 for a zero quantized value 142. The cell around zero is divided into three uniform new cells.

[0057] For a zero quantized value, the residual quantization Qr performed by the residual quantization stage 106 may be summarized as follows: TIFF2026010118000004.tif43169 where C depends on the dead zone of the quantization stage, C=delta*(fac_z / 2) where prm is the bitstream generated by residual quantization stage 106 using the quantized residual values, x[i] is the input signal, and x_Q[i] is the dequantized input signal. Index n is incremented by 1 for each zero quantized value that is requantized to zero, and n is incremented by 2 for each zero quantized value that is requantized to non-zero.

[0058] Then, the inverse Qr can be expressed as: TIFF2026010118000005.tif32166

[0059] Embodiments of the present invention can be easily extended to assume that the distribution within the original quantization cells is not uniform. In this case, the relative reproduction levels can be derived depending on the distribution of the quantization error. One way to achieve this is to divide the original quantization cells into new smaller cells that are non-uniform. A second dead-zone parameter can be used as well.

[0060] Further embodiments of the encoder 100 and decoder 120 are outlined below.

[0061] First, the encoder 100 will be described.

[0062] Residual quantization is a refinement quantization layer that refines the first SQ stage (or quantization stage 102). It uses the incidentally unused bits, i.e. unused bits = target_bits-nbbits where nbbits is the number of bits consumed by the entropy encoder 104. Residual quantization employs a greedy strategy and does not employ entropy, in order to stop encoding whenever the bitstream reaches the desired size.

[0063] Refinement consists of requantizing the quantized spectrum line by line: First, the non-zero quantized lines are processed using a 1-bit residual quantizer. TIFF2026010118000006.tif32167

[0064] where X[k] is the scaled sample of the input signal 140, TIFF2026010118000007.tif11166 are the corresponding scaled samples of the dequantized input signal 152.

[0065] Finally, if the remaining bits allow, the zero quantized lines are considered and quantized using three levels as follows: TIFF2026010118000008.tif47164

[0066] where X[k] is the scaled sample of the input signal 140, TIFF2026010118000009.tif11166 is the corresponding scaled sample of the inverse quantized input signal 152, and fac_z is a normalized absolute value that may indicate the value by which the normalized absolute value of the inverse quantization level 172 should be increased to obtain a first refined inverse quantization level 174 of the two refined inverse quantization levels 174 and 176, or may indicate the value by which the normalized absolute value of the inverse quantization level 172 should be decreased to obtain a second refined inverse quantization level 176 of the two refined inverse quantization levels 174 and 176, rounding_dz=1-dz / 2 is.

[0067] Second, the decoder 120 will be described.

[0068] The remaining bits refine the non-zero decoded line: one bit is read for each non-zero spectral value. TIFF2026010118000010.tif62164

[0069] where X[k] is the input signal 140, TIFF2026010118000011.tif11166 is the inverse quantized input signal 152, fac_p may be a normalized absolute value by which the normalized absolute value of the inverse quantization level (or reproduction level) 172 should be increased to obtain a first refined inverse quantization level 174 of the two refined inverse quantization levels 174 and 176, and fac_m may be a normalized absolute value by which the normalized absolute value of the inverse quantization level 172 should be decreased to obtain a second refined inverse quantization level 176 of the two refined inverse quantization levels 174 and 176, rounding_dz=1-dz / 2 is.

[0070] If at least two bits are left to read, the zero value is refined as follows: TIFF2026010118000012.tif62164

[0071] where X[k] is the scaled sample of the input signal 140, TIFF2026010118000013.tif11166 is the corresponding scaled sample of the inverse quantized input signal 152, and fac_z may be a normalized absolute value by which the normalized absolute value of the inverse quantization level 172 should be increased to obtain a first refined inverse quantization level 174 of the two refined inverse quantization levels 174 and 176, or may be a normalized absolute value by which the normalized absolute value of the inverse quantization level 172 should be decreased to obtain a second refined inverse quantization level 176 of the two refined inverse quantization levels 174 and 176, rounding_dz=1-dz / 2 is.

[0072] 8 is a flowchart of an encoding method 200 according to one embodiment, comprising the steps of quantizing an input signal using a dead zone to obtain a plurality of quantized values ​​202, encoding the plurality of quantized values ​​using an entropy coding scheme to obtain a plurality of entropy coded values ​​204, quantizing a residual signal resulting from quantization by the quantization stage 206 to determine a plurality of quantized residual values ​​depending on the dead zone of the quantization stage, and forming a bitstream from the plurality of entropy coded values ​​and the plurality of quantized residual values ​​208.

[0073] 9 is a flowchart of a decoding method 220 according to one embodiment, which comprises a step 222 of analysing an encoded signal to obtain a plurality of entropy-coded values ​​and a quantised residual value, a step 224 of decoding the plurality of entropy-coded values ​​using an entropy decoding scheme to obtain a plurality of quantised values, a step 226 of dequantising the plurality of quantised values ​​using a dead zone to obtain an output signal, and a step 228 of refining the dequantisation level used to obtain the output signal depending on the dead zone and the quantised residual value.

[0074] Although some aspects have been described above in the context of an apparatus, these aspects also represent a description of a corresponding method, and it is clear that a block or apparatus corresponds to a method step or feature of a method step. Similarly, aspects described in the context of a method step also represent a corresponding block or item or feature of a corresponding apparatus. Some or all of the method steps may be performed by (using) a hardware apparatus, such as, for example, a microprocessor, a programmable computer, or electronic circuitry. In some embodiments, one or more of the most important method steps may be performed by such an apparatus.

[0075] Depending on certain implementation requirements, embodiments of the present invention can be implemented in hardware or software. This implementation can be implemented using a digital storage medium, such as a floppy disk, DVD, Blu-ray, CD, ROM, PROM, EPROM, EEPROM, flash memory, or the like, having electronically readable control signals stored therein and cooperating (or capable of cooperating) with a programmable computer system to perform the methods of the present invention. Thus, the digital storage medium can be computer-readable.

[0076] Some embodiments according to the invention include a data carrier having electronically readable control signals cooperable with a computer system programmable to carry out one of the methods described above.

[0077] Generally, embodiments of the present invention may be configured as a computer program product having program code operable to perform one of the methods of the present invention when the computer program product runs on a computer, the program code may for example be stored on a machine readable carrier.

[0078] Other embodiments of the invention comprise the computer program stored on a machine readable carrier for performing one of the methods described above.

[0079] In other words, an embodiment of the inventive method is, therefore, a computer program having a program code for performing one of the above described methods, when the computer program runs on a computer.

[0080] Another embodiment of the invention is a data carrier (or a non-transitory storage medium such as a digital storage medium or a computer readable medium) comprising a computer program recorded thereon for performing one of the methods described above. The data carrier, digital storage medium or recorded medium is typically tangible and / or non-transitory.

[0081] Another embodiment of the invention is, therefore, a data stream or a sequence of signals representing the computer program for performing one of the methods described above, which data stream or sequence of signals may be adapted to be transmitted via a data communication connection, for example the Internet.

[0082] Another embodiment comprises a processing means, for example a computer, or a programmable logic device, configured to or adapted to perform one of the methods described above.

[0083] Another embodiment comprises a computer having installed thereon the computer program for performing one of the methods described above.

[0084] Further embodiments according to the invention include a device or a system configured to transmit (e.g. electronically or optically) a computer program for performing one of the above-mentioned methods to a receiver, which may be e.g. a computer, a mobile device, a memory device, etc. The device or system may for example comprise a file server for transmitting the computer program to the receiver.

[0085] In some embodiments, a programmable logic device (such as a field programmable gate array) may be used to perform some or all of the functions of the methods described above. In some embodiments, a field programmable gate array may cooperate with a microprocessor to perform one of the methods described above. In general, such methods may be suitably performed by any hardware apparatus.

[0086] The above-described embodiments are merely illustrative of the principles of the present invention. Modifications and variations in the arrangements and details described herein will be apparent to those skilled in the art. Therefore, the present invention is not to be limited by the specific details presented herein for purposes of illustration and description of the embodiments, but should be limited only by the scope of the appended claims. -remarks- [Claim 1] a quantization stage (102) configured to quantize an input signal (140) using a dead zone to obtain a plurality of quantized values ​​(142); an entropy encoder (104) configured to encode the plurality of quantized values ​​(142) using an entropy coding scheme to obtain a plurality of entropy coded values ​​(144); a residual quantization stage (106) configured to quantize a residual signal resulting from the quantization stage (102), the residual quantization stage (106) configured to determine, for one non-zero quantized value, at least one quantized residual value (146) depending on the dead zone of the quantization stage (102); a coded signal forming unit (108) configured to form a coded signal (148) from the plurality of entropy coded values ​​(144) and the at least one quantized residual value (146); An encoding device (100) including: [Claim 2] 2. The encoding device (100) of claim 1, wherein the residual quantization stage (106) is configured to determine, for one non-zero quantized value, at least one quantized residual value (146) depending on the width of the dead zone of the quantization stage (102). [Claim 3] the residual quantization stage (106) comprises an inverse quantization unit (160) configured to inverse quantize the plurality of quantized values ​​(112) depending on the dead zone of the quantization stage (102) to obtain an inverse quantized input signal (152); the residual quantization stage (106) is configured to determine the at least one quantized residual value (146) such that the quantized residual value (146) includes one bit for each non-zero quantized value; 3. The encoding device of claim 1, wherein the residual quantization stage is configured to determine, for the non-zero quantized values, the quantized residual value to comprise a logical 0 when the input signal is smaller than the dequantized input signal, and to determine, for the non-zero quantized values, the quantized residual value to comprise a logical 1 otherwise. [Claim 4] The residual quantization stage (106) an inverse quantization unit (160) configured to inverse quantize the plurality of quantized values ​​(142) in dependence on the dead zone to obtain an inverse quantized input signal (152); a comparator (162) configured to compare the input signal (140) with the dequantized input signal (152); An encoding device (100) according to any one of claims 1 to 3. [Claim 5] the comparison unit (162) is configured to compare the input signal (140) with the dequantized input signal (152) to obtain the residual signal (154); the residual quantization stage (106) is configured to quantize the residual signal (154) in dependence on the dead zone; The encoding device (100) according to claim 4. [Claim 6] the residual quantization stage (106) is configured to determine the at least one quantized residual value (146) such that the quantized residual value (146) includes one bit for each non-zero quantized value; 6. The encoding device (100) of claim 5, wherein the residual quantization stage is configured to determine, for the non-zero quantized value, the quantized residual value (146) to contain a logical value of 0 when the residual signal (154) is negative for the non-zero quantized value, and to determine, for the non-zero quantized value otherwise, the quantized residual value (146) to contain a logical value of 1. [Claim 7] the residual quantization stage (106) is configured to determine the at least one quantized residual value (146) such that the quantized residual value (146) includes one bit for each non-zero quantized value; The residual quantization stage (106) is configured to determine the quantized residual value (146) according to the following syntax: TIFF2026010118000014.tif21164 where prm is the bitstream generated by the residual quantization stage (106) using the quantized residual values ​​(146), x[i] is the input signal (140), x_Q[i] is the dequantized input signal (152), n is an index that is incremented by one for each non-zero quantized value, and i is an index that is incremented by one for each resulting quantized value (142). An encoding device (100) according to any one of claims 1 to 6. [Claim 8] the residual quantization stage (106) is configured to determine the quantized residual value (146) such that the quantized residual value (146) comprises two bits for a quantized value of one zero; The residual quantization stage (106) is configured to determine the quantized residual value (146) according to the following syntax: TIFF2026010118000015.tif43169 where C depends on the dead zone of the quantization stage (102), prm is the bitstream generated by the residual quantization stage (106) using the quantized residual values ​​(146), x[i] is the input signal (140), x_Q[i] is the dequantized input signal (152), n is an index that is incremented by 1 for each zero quantized value that is requantized to a zero quantized value and by 2 for each zero quantized value that is requantized to a non-zero quantized value, and i is an index that is incremented by 1 for each resulting quantized value (142). An encoding device (100) according to any one of claims 1 to 7. [Claim 9] the coded signal forming unit (108) is configured to form the coded signal (148) by appending the at least one quantized residual value (146) or multiple quantized residual values ​​(146) to the multiple entropy coded values ​​(144) until the coded signal (148) has a maximum length available for transmission to a decoder. An encoding device (100) according to any one of claims 1 to 8. [Claim 10] the coded signal forming unit (108) is configured to provide a bitstream as the coded signal (148), the coded signal forming unit (108) being configured to form the bitstream from the plurality of entropy coded values ​​(144) and the plurality of quantized residual values ​​(146); the coded signal forming unit (108) is configured to add the quantized residual values ​​(146) to the entropy coded values ​​(144); The residual quantization stage (106) a residual quantization unit (106'); an adjustment unit (164) for controlling the residual quantization unit (106') to quantize the residual signal depending on the width of the dead zone used in the quantization stage (102) to obtain the plurality of quantized values ​​(142); the adjustment unit (164) is configured to obtain a target number of bits and a number of consumed bits; the adjustment unit (164) is configured to control the residual quantization stage to stop determining quantized residual values ​​when the bitstream contains the target number of bits. An encoding device (100) according to any one of claims 1 to 9. [Claim 11] a coded signal analyzer (122) configured to analyze a coded signal (148) to obtain a plurality of entropy coded values ​​(144) and at least one quantized residual value (146); an entropy decoder (124) configured to decode the plurality of entropy-coded values ​​(144) using an entropy decoding scheme to obtain a plurality of quantized values ​​(142); an inverse quantization stage (126) configured to inverse quantize the plurality of quantized values ​​(142) to obtain an output signal (150); the inverse quantization stage (126) is configured to refine the inverse quantization levels (172) used to obtain the output signal (150) depending on the quantized residual values ​​(146) and a dead zone; A decoding device (120). [Claim 12] the inverse quantization stage (126) is configured to refine the inverse quantization levels (172) for non-zero quantized values ​​depending on the quantized residual values ​​(146) and the width of the dead zone; A decoding device (120) according to claim 11. [Claim 13] the inverse quantization stage (126) is configured to refine the inverse quantization levels (172) by determining refined inverse quantization levels (174, 176) depending on the dead zone; A decoding device (120) according to claim 11 or 12. [Claim 14] the inverse quantization stage (126) is configured to determine two refined inverse quantization levels (174, 176) for one non-zero quantized value; the inverse quantization stage (126) is configured to obtain the output signal (150) using one of the two refined inverse quantization levels (174, 176) indicated by the quantized residual value; A decoding device (120) according to claim 13. [Claim 15] the inverse quantization stage (126) is configured to increase the normalized absolute value of the inverse quantization level (172) by an increment value to obtain a first of the two refined inverse quantization levels (174); the inverse quantization stage (126) is configured to reduce the normalized absolute value of the inverse quantization level (172) by a reduction value to obtain a second of the two refined inverse quantization levels (174); the increase value and the decrease value are different from each other; A decoding device (120) according to claim 14. [Claim 16] The inverse quantization stage (126) is configured to determine the two refined inverse quantization levels (174, 176) for a non-zero quantized value based on two factors: fac_p = 0,25 * dz fac_m = 0.5 * (1 - 0.5 * dz) where fac_p denotes the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be increased to obtain the first level (174) of the two refined inverse quantization levels, fac_m denotes the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be decreased to obtain the second level (176) of the two refined inverse quantization levels, and dz is the normalized width of the dead zone. A decoding device (120) according to claim 14 or 15. [Claim 17] the inverse quantization stage (126) is configured to determine two refined inverse quantization levels (174, 176) for a quantized value of one zero; the inverse quantization stage (126) is configured to obtain the output signal (150) using the inverse quantization level (172) and one of the two refined inverse quantization levels (174, 176) indicated by the quantized residual value; A decoding device (120) according to any one of claims 13 to 16. [Claim 18] the inverse quantization stage (126) is configured to increase the normalized absolute value of the inverse quantization level (172) by an increment value to obtain a first of the two refined inverse quantization levels (174); the inverse quantization stage (126) is configured to reduce the normalized absolute value of the inverse quantization level (172) by a reduction value to obtain a second of the two refined inverse quantization levels (174); A decoding device (120) according to claim 17. [Claim 19] The inverse quantization stage (126) is configured to determine the two refined inverse quantization levels (174, 176) for the zero quantized value based on the following factors: fac_z = dz / 3 where fac_z denotes the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be increased to obtain the first of the two refined inverse quantization levels (174), and the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be decreased to obtain the second of the two refined inverse quantization levels (176), and dz is the normalized width of the dead zone. A decoding device (120) according to claim 17 or 18. [Claim 20] A coding device (100) according to any one of claims 1 to 10, A decoding device (120) according to any one of claims 11 to 19. [Claim 21] quantizing (202) an input signal to obtain a plurality of quantized values; an encoding step (204) of encoding the plurality of quantized values ​​using an entropy coding scheme to obtain a plurality of entropy coded values; quantizing (206) a residual signal resulting from quantization by the quantization stage and determining a plurality of quantized residual values ​​depending on the dead zone of the quantization stage; forming (208) a bitstream from the plurality of entropy coded values ​​and the plurality of quantized residual values; An encoding method (200) comprising: [Claim 22] analyzing (222) the coded signal to obtain a plurality of entropy coded values ​​and a quantized residual value; decoding (224) the plurality of entropy-encoded values ​​using an entropy decoding scheme to obtain a plurality of quantized values; dequantizing (226) the plurality of quantized values ​​to obtain an output signal; Refining (228) the inverse quantization levels used to obtain the output signal depending on a dead zone and the quantized residual value; A decoding method (220) including: [Claim 23] 23. A computer program for carrying out the method according to claim 21 or 22.

Claims

1. a quantization stage (102) configured to quantize an input signal (140) using a dead zone to obtain a plurality of quantized values ​​(142); an entropy encoder (104) configured to encode the plurality of quantized values ​​(142) using an entropy coding scheme to obtain a plurality of entropy coded values ​​(144); a residual quantization stage (106) configured to quantize a residual signal resulting from the quantization stage (102), the residual quantization stage (106) configured to determine, for one non-zero quantized value, at least one quantized residual value (146) depending on the dead zone of the quantization stage (102); a coded signal forming unit (108) configured to form a coded signal (148) from the plurality of entropy coded values ​​(144) and the at least one quantized residual value (146); An encoding device (100) comprising:

2. 2. The encoding device (100) of claim 1, wherein the residual quantization stage (106) is configured to determine, for one non-zero quantized value, at least one quantized residual value (146) depending on the width of the dead zone of the quantization stage (102).

3. the residual quantization stage (106) comprises an inverse quantization unit (160) configured to inverse quantize the plurality of quantized values ​​(112) depending on the dead zone of the quantization stage (102) to obtain an inverse quantized input signal (152); the residual quantization stage (106) is configured to determine the at least one quantized residual value (146) such that the quantized residual value (146) comprises one bit for each non-zero quantized value; 3. The encoding device of claim 1, wherein the residual quantization stage is configured to determine, for the non-zero quantized values, the quantized residual values ​​to comprise a logical 0 when the input signal is smaller than the inverse quantized input signal, and to determine, for the non-zero quantized values, the quantized residual values ​​to comprise a logical 1 otherwise.

4. The residual quantization stage (106) an inverse quantization unit (160) configured to inverse quantize the plurality of quantized values ​​(142) depending on the dead zone to obtain an inverse quantized input signal (152); a comparison unit (162) configured to compare the input signal (140) with the dequantized input signal (152), Encoding device (100) according to any one of claims 1 to 3.

5. the comparison unit (162) is configured to compare the input signal (140) with the dequantized input signal (152) to obtain the residual signal (154); the residual quantization stage (106) is configured to quantize the residual signal (154) in dependence on the dead zone; The encoding device (100) of claim 4.

6. the residual quantization stage (106) is configured to determine the at least one quantized residual value (146) such that the quantized residual value (146) comprises one bit for each non-zero quantized value; 6. The encoding device (100) of claim 5, wherein the residual quantization stage is configured to determine, for the non-zero quantized value, the quantized residual value (146) to comprise a logical 0 when the residual signal (154) is negative for the non-zero quantized value, and to determine, for the non-zero quantized value otherwise, the quantized residual value (146) to comprise a logical 1.

7. the residual quantization stage (106) is configured to determine the at least one quantized residual value (146) such that the quantized residual value (146) comprises one bit for each non-zero quantized value; The residual quantization stage (106) is configured to determine the quantized residual values ​​(146) according to the following syntax: where prm is the bitstream generated by the residual quantization stage (106) using the quantized residual values ​​(146), x[i] is the input signal (140), x_Q[i] is the dequantized input signal (152), n is an index that is incremented by one for each non-zero quantized value, and i is an index that is incremented by one for each resulting quantized value (142). Encoding device (100) according to any one of claims 1 to 6.

8. the residual quantization stage (106) is configured to determine the quantized residual value (146) such that the quantized residual value (146) comprises two bits for a quantized value of one zero; The residual quantization stage (106) is configured to determine the quantized residual values ​​(146) according to the following syntax: where C depends on the dead zone of the quantization stage (102), prm is the bitstream generated by the residual quantization stage (106) using the quantized residual values ​​(146), x[i] is the input signal (140), x_Q[i] is the dequantized input signal (152), n is an index that is incremented by 1 for each zero quantized value that is requantized to a zero quantized value and by 2 for each zero quantized value that is requantized to a non-zero quantized value, and i is an index that is incremented by 1 for each resulting quantized value (142). Encoding device (100) according to any one of claims 1 to 7.

9. the coded signal forming unit (108) is configured to form the coded signal (148) by appending the at least one quantized residual value (146) or multiple quantized residual values ​​(146) to the multiple entropy coded values ​​(144) until the coded signal (148) has a maximum length available for transmission to a decoder. Encoding device (100) according to any one of claims 1 to 8.

10. the coded signal forming unit (108) is configured to provide a bitstream as the coded signal (148), the coded signal forming unit (108) being configured to form the bitstream from the plurality of entropy coded values ​​(144) and the plurality of quantized residual values ​​(146); the coded signal forming unit (108) is configured to add the quantized residual values ​​(146) to the entropy coded values ​​(144); The residual quantization stage (106) a residual quantization unit (106'); an adjustment unit (164) for controlling the residual quantization unit (106′) to quantize the residual signal depending on the width of the dead zone used in the quantization stage (102) to obtain the plurality of quantized values ​​(142); The adjustment unit (164) is configured to obtain a target number of bits and a number of consumed bits; the adjustment unit (164) is configured to control the residual quantization stage to stop determining quantized residual values ​​when the bitstream contains the target number of bits. Encoding device (100) according to any one of claims 1 to 9.

11. a coded signal analyzer (122) configured to analyze the coded signal (148) to obtain a plurality of entropy coded values ​​(144) and at least one quantized residual value (146); an entropy decoder (124) configured to decode the plurality of entropy-coded values ​​(144) using an entropy decoding scheme to obtain a plurality of quantized values ​​(142); an inverse quantization stage (126) configured to inverse quantize the plurality of quantized values ​​(142) to obtain an output signal (150); the inverse quantization stage (126) is configured to refine the inverse quantization levels (172) used to obtain the output signal (150) depending on the quantized residual values ​​(146) and a dead zone; A decoding device (120).

12. the inverse quantization stage (126) is configured to refine the inverse quantization levels (172) for non-zero quantized values ​​depending on the quantized residual values ​​(146) and the width of the dead zone; A decoding device (120) according to claim 11.

13. the inverse quantization stage (126) is configured to refine the inverse quantization levels (172) by determining refined inverse quantization levels (174, 176) depending on the dead zone; Decoding device (120) according to claim 11 or 12.

14. the inverse quantization stage (126) is configured to determine two refined inverse quantization levels (174, 176) for one non-zero quantized value; the inverse quantization stage (126) is configured to obtain the output signal (150) using one of the two refined inverse quantization levels (174, 176) indicated by the quantized residual value; A decoding device (120) according to claim 13.

15. the inverse quantization stage (126) is configured to increase the normalized absolute value of the inverse quantization level (172) by an increment value to obtain a first of the two refined inverse quantization levels (174); the inverse quantization stage (126) is configured to reduce the normalized absolute value of the inverse quantization level (172) by a reduction value to obtain a second of the two refined inverse quantization levels (174); the increase value and the decrease value are different from each other; A decoding device (120) according to claim 14.

16. The inverse quantization stage (126) is configured to determine the two refined inverse quantization levels (174, 176) for a single non-zero quantized value based on two factors: fac_p = 0,25 * dz fac_m = 0.5 * (1 - 0.5 * dz) where fac_p denotes the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be increased to obtain the first level (174) of the two refined inverse quantization levels, fac_m denotes the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be decreased to obtain the second level (176) of the two refined inverse quantization levels, and dz is the normalized width of the dead zone. Decoding device (120) according to claim 14 or 15.

17. the inverse quantization stage (126) is configured to determine two refined inverse quantization levels (174, 176) for a quantized value of one zero; the inverse quantization stage (126) is configured to obtain the output signal (150) using the inverse quantization level (172) and one of the two refined inverse quantization levels (174, 176) indicated by the quantized residual value; A decoding device (120) according to any one of claims 13 to 16.

18. the inverse quantization stage (126) is configured to increase the normalized absolute value of the inverse quantization level (172) by an increment value to obtain a first of the two refined inverse quantization levels (174); the inverse quantization stage (126) is configured to reduce the normalized absolute value of the inverse quantization level (172) by a reduction value to obtain a second of the two refined inverse quantization levels (174); 18. A decoding device (120) according to claim 17.

19. The inverse quantization stage (126) is configured to determine the two refined inverse quantization levels (174, 176) for the zero quantized value based on the following factors: fac_z = dz / 3 where fac_z denotes the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be increased to obtain the first of the two refined inverse quantization levels (174), and the normalized absolute value by which the normalized absolute value of the inverse quantization level (172) should be decreased to obtain the second of the two refined inverse quantization levels (176), and dz is the normalized width of the dead zone. Decoding device (120) according to claim 17 or 18.

20. A coding device (100) according to any one of claims 1 to 10, A decoding device (120) according to any one of claims 11 to 19.

21. quantizing (202) an input signal to obtain a plurality of quantized values; an encoding step (204) of encoding the plurality of quantized values ​​using an entropy coding scheme to obtain a plurality of entropy coded values; quantizing (206) a residual signal resulting from quantization by the quantization stage and determining a plurality of quantized residual values ​​depending on the dead zone of the quantization stage; forming (208) a bitstream from the plurality of entropy coded values ​​and the plurality of quantized residual values; 20. A coding method (200) comprising:

22. analyzing (222) the coded signal to obtain a plurality of entropy coded values ​​and a quantized residual value; decoding (224) the plurality of entropy-encoded values ​​using an entropy decoding scheme to obtain a plurality of quantized values; dequantizing (226) the plurality of quantized values ​​to obtain an output signal; Refining (228) the inverse quantization levels used to obtain the output signal depending on a dead zone and the quantized residual value; A decoding method (220) comprising:

23. 23. A computer program for carrying out the method according to claim 21 or 22.

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