Energy dependent quantization for efficient coding of spatial audio parameters
Parameters being a measure for a characteristic of a channel or of a pair of channels, wherein the parameter is a measure for a characteristic of the channel or of the pair of channels with respect to another channel of a multi-channel signal can be quantized more efficiently using a quantization rule that is generated based on a relation of an energy measure of the channel or the pair of channels and an energy measure of the multi-channel signal. With generation of the quantization rule taking into account a psycho acoustic approach, the size of an encoded representation of the multi-channel signal can be decreased by coarser quantization without significantly disturbing the perceptual quality of the multi-channel signal when reconstructed from the encoded representation.
1. A parameter dequantizer for dequantizing a quantized parameter to derive a parameter, wherein the parameter is a measure for a characteristic of a single channel or a pair of channels with respect to another single channel or a pair of channels of a multi-channel signal including a plurality of channels, comprising:
a dequantization rule generator for generating a dequantization rule based on a relation between an energy measure derived from the single channel or the pair of channels and an energy measure derived from at least two channels of the multi-channel signal;
a value dequantizer for deriving the parameter from the quantized parameter, using the generated dequantization rule; and
the dequantization rule generator or the value dequantizer including a hardware implementation.
2. The parameter dequantizer according to claim 1 , in which the dequantization rule generator is operative to use an energy measure derived from at least two channels of the multi-channel signal which is derived from a combination of channels not having the channel or the pair of channels.
3. The parameter dequantizer according to claim 1 , in which the dequantization rule generator is operative to generate the dequantization rule such that a dequantization is coarser for a channel or a pair of channels having a low energy measure than for a channel or a pair of channels having a high energy measure.
4. The parameter dequantizer according to claim 1 , in which the dequantization rule generator is operative to choose one dequantization rule from two or more fixed dequantization rules stored in a memory.
5. The parameter dequantizer according to claim 1 , in which the dequantization rule generator is operative to calculate the new dequantization rule based on a relation between the energy measure derived from the channel or the pair of channels and the energy measure derived from at least two channels of the multi-channel signal.
6. The parameter dequantizer according to claim 1 , in which the dequantization rule generator is operative such that the calculation of the dequantization rule comprises a calculation of a scale factor.
7. The parameter dequantizer according to claim 6 , in which the dequantization rule generator further comprises a parameter scaler for modifying the parameter using the scale factor.
8. The parameter dequantizer according to claim 6 , in which the parameter scaler is operative to modify the parameter such that the modification includes a multiplication of the parameter by the scale factor.
9. The parameter dequantizer according to claim 6 , in which the dequantization rule generator further comprises a decompressor for deriving an intermediate quantized parameter from the quantized parameter using the scale factor; and in which the value dequantizer is operative to derive the parameter from the intermediate quantized parameter using a fixed dequantization rule.
10. The parameter dequantizer according to claim 9 , in which the decompressor is operative to derive the intermediate quantized parameter by multiplication of the scale factor and the quantized parameter.
11. The parameter dequantizer according to claim 9 , in which the dequantization rule generator further comprises a rounder to derive an integer valued intermediate quantized parameter from the intermediate quantized parameter; and in which the value dequantizer is operative to derive the parameter from the integer valued intermediate quantized parameter using a fixed dequantization rule.
12. The parameter dequantizer according to claim 1 , in which the quantized parameter is a measure for an energy relation between a combination of a left-front channel and a right-front channel and a combination of a center-channel and a low-frequency-enhancement-channel;
the energy measure is an energy measure for a pair of channels having a first channel combined from the front-left and the front-right channel and having a second channel combined from the center-channel and the low-frequency-enhancement-channel; and
the energy measure derived from at least two channels of the multi-channel signal is an energy measure derived from a combination of a back-left and a back-right channel.
13. The parameter dequantizer according to claim 1 , in which the quantized parameter is a measure for an energy relation between a back-left and a back-right channel;
the energy measure is an energy measure for a pair of channels having the back-left and the back-right channel; and
the energy measure derived from at least two channels of the multi-channel signal is an energy measure derived from a combination of a left-front, a right-front, a center and a low-frequency-enhancement channel.
14. The parameter dequantizer according to claim 1 , in which the quantized parameter is a measure for an energy relation between a front-left and a front-right channel;
the energy measure is a measure for a pair of channels having the front-left and the front-right channel; and
the energy measure derived from at least two channels of the multi-channel signal is an energy measure derived from a combination of a center and a low-frequency-enhancement channel.
15. The parameter dequantizer according to claim 1 , in which the quantized parameter is a measure for an energy relation between a combination of left-front and a left-back channel and a combination of a right-front and a right-back channel;
the energy measure is an energy measure for a pair of channels having a first channel combined from the left-front and the left-back channel and having a second channel combined from the right-front and the right-back channel; and
the energy measure derived from at least two channels of the multi-channel signal is an energy measure derived from a combination of a center and a low-frequency-enhancement channel.
16. The parameter dequantizer according to claim 1 , in which the quantized parameter is a measure for an energy relation between a left-front and a left-back channel;
the energy measure is an energy measure for a pair of channels having the left-front and the left-back channel; and
the energy measure derived from at least two channels of the multi-channel signal is an energy measure derived from a combination of a right-front and a right-back channel.
17. The parameter dequantizer according to claim 1 , in which the quantized parameter is a measure for an energy relation between a right-front and a right-back channel;
the energy measure is an energy measure derived from a pair of channels having the right-front and the right-back channel; and
the energy measure derived from at least two channels of the multi-channel signal is an energy measure derived from a combination of a left-front and a left-back channel.
18. The parameter dequantizer according to claim 1 , in which the dequantization rule generator is operative to generate a dequantization rule such that an application of the dequantization rule to the quantized parameter comprises an assignment of the quantized parameter to a parameter.
19. The parameter dequantizer according to claim 1 , further comprising a differential decoder and a Huffman decoder, wherein the Huffman decoder is operative to derive a Huffman decoded representation of a received Huffman encoded representation; and wherein the differential decoder is operative to derive the quantized parameter from the Huffman decoded representation.
20. The parameter dequantizer according to claim 1 , in which the parameter is a spatial parameter, describing a spatial perception of the multi-channel audio signal, and in which the input parameter is chosen from the following list of parameters: inter-channel correlation/coherence (ICC), inter-channel level/intensity difference (ICLD or IID), inter-channel phase difference (IPD), and inter-channel time difference (ICTD).
21. A multi-channel decoder for generating a reconstruction of a multi-channel signal, comprising:
a parameter dequantizer according to claim 1 ; and
an up-mixer for up-mixing the reconstruction of the multi-channel signal from a transmitted downmixed signal using parameters dequantized by the parameter dequantizer.
22. A method of dequantizing a quantized parameter to derive a parameter, wherein the parameter is a measure for a characteristic of a single channel or a pair of channels with respect to another single channel or a pair of channels of a multi-channel signal including a plurality of channels, the method comprising:
generating, by a dequantization rule generator, a dequantization rule based on a relation between an energy measure derived from the channel or the pair of channels and an energy measure derived from at least two channels of the multi-channel signal;
deriving, by a value dequantizer, the parameter from the quantized parameter using the generated dequantization rule; and
the dequantization rule generator or the value dequantizer including a hardware implementation.
23. A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer, a method in accordance with claim 22 .
24. A receiver or audio player, having a parameter dequantizer for dequantizing a quantized parameter to derive a parameter, wherein the parameter is a measure for a characteristic of a single channel or a pair of channels with respect to another single channel or a pair of channels of a multi-channel signal, comprising:
a dequantization rule generator for generating a dequantization rule based on a relation between an energy measure derived from the channel or the pair of channels and an energy measure derived from at least two channels of the multi-channel signal;
a value dequantizer for deriving the parameter from the quantized parameter, using the generated dequantization rule; and
the dequantization rule generator or the value dequantizer including a hardware implementation.
25. A method of receiving or audio playing, the method having a method of dequantizing a quantized parameter to derive a parameter, wherein the parameter is a measure for a characteristic of a single channel or a pair of channels with respect to another single channel or a pair of channels of a multi-channel signal, the method comprising:
generating, by a dequantization rule generator, a dequantization rule based on a relation between an energy measure derived from the channel or the pair of channels and an energy measure derived from at least two channels of the multi-channel signal;
deriving, by a value dequantizer, the parameter from the quantized parameter using the generated dequantization rule; and
the dequantization rule generator or the value dequantizer including a hardware implementation.
26. A non-transitory storage medium having stored thereon a computer program for performing, when running on a computer, a method in accordance with claim 25 .