Optimized coding and decoding of spatialization information for the parametric coding and decoding of a multichannel audio signal
A method of parametric coding of a multichannel digital audio signal including coding a signal arising from a channels reduction processing applied to the multichannel signal and coding spatialization information of the multichannel signal. The method includes the following acts: extraction of a plurality of items of spatialization information of the multichannel signal; obtaining at least one representation model of the extracted spatialization information; determination of at least one angle parameter of a model obtained; coding the at least one determined angle parameter so as to code the spatialization information extracted during the coding of spatialization information. Also provided are a method for decoding such a coded signal and corresponding coding and decoding devices.
1. A method comprising:
parametric coding a multichannel digital audio signal comprising the following acts performed by a coding device:
coding a signal arising from a channels reduction processing applied to the multichannel signal;
coding spatialization cues in respect of the multichannel signal, which comprises:
extracting a plurality of spatialization cues in respect of the multichannel signal;
obtaining at least one representation model of the spatialization cues extracted;
determining at least one angle parameter of a model obtained; and
coding of the at least one determined angle parameter so as to code the spatialization cues extracted during the coding of spatialization cues; and
transmitting the coded signal and the coded at least one determined angle parameter on a communication network or storing the coded signal and the coded at least one determined angle parameter in a non-transitory computer-readable medium.
2. The coding method as claimed in claim 1 , wherein the spatialization cues are defined by frequency sub-bands of the multichannel audio signal and at least one angle parameter per sub-band is determined and coded.
3. The method as claimed in claim 1 , wherein the method furthermore comprises calculating a reference spatialization cue and coding this reference spatialization cue.
4. The coding method as claimed in claim 1 , wherein one of the spatialization cues is an interchannel time shift (ITD) cue.
5. The coding method as claimed in claim 1 , wherein one of the spatialization cues is an interchannel intensity difference (ILD) cue.
6. The method as claimed in claim 5 , wherein the method furthermore comprises the following acts for coding an interchannel intensity difference cue:
estimating an interchannel intensity difference cue on the basis of the model obtained and of the angle parameter determined;
coding the difference between the interchannel intensity difference cue extracted and estimated.
7. The method as claimed in claim 1 , wherein a spatialization-cue-based representation model is obtained.
8. The method as claimed in claim 1 , wherein a representation model common to several spatialization cues is obtained.
9. The coding method as claimed in claim 1 , wherein the act of obtaining of a representation model of the spatialization cues is performed by selecting from a table of models defined for various values of the spatialization cues.
10. The method as claimed in claim 9 , wherein an index of the table corresponding to the selected model is coded.
11. A parametric coder of a multichannel digital audio signal, comprising:
a processor; and
a non-transitory computer-readable medium comprising instructions stored thereon, which when executed by the processor configure the parametric coder to perform acts to parametric code the multichannel digital audio signal:
coding a signal arising from a channels reduction processing applied to the multichannel signal;
coding spatialization cues in respect of the multichannel signal, which comprises:
extracting a plurality of spatialization cues in respect of the multichannel signal;
obtaining at least one representation model of the spatialization cues extracted;
determining at least one angle parameter of a model obtained; and
coding the at least one determined angle parameter so as to code the spatialization cues extracted during the coding of spatialization cues; and
transmitting the coded signal and the coded at least one determined angle parameter on a communication network or storing the coded signal and the coded at least one determined angle parameter in a storage medium.
12. A non-transitory computer-readable medium on which is recorded a computer program comprising code instructions for execution of a method of parametric coding a multichannel digital audio signal when the instructions are executed by a processor of a coding device, wherein the method comprises:
coding a signal arising from a channels reduction processing applied to the multichannel signal;
coding spatialization cues in respect of the multichannel signal, which comprises:
extracting a plurality of spatialization cues in respect of the multichannel signal;
obtaining at least one representation model of the spatialization cues extracted;
determining at least one angle parameter of a model obtained; and
coding the at least one determined angle parameter so as to code the spatialization cues extracted during the coding of spatialization cues; and
transmitting the coded signal and the coded at least one determined angle parameter on a communication network or storing the coded signal and the coded at least one determined angle parameter in a storage medium.