Binaural spatialization of compression-encoded sound data utilizing phase shift and delay applied to each subband

摘要

The invention is aimed at improving the quality of the filtering by transfer functions of HRTF type of signals (L, R) compressed in a transformed domain, for binaural playing on two channels (L-BIN, R-BIN), using a combination of HRTF filters (hL,L, hL,R) including a decorrelated version (HRTF-C*, HRTF-E*) of a few of these filters. For this purpose, a decorrelation cue is given with spatialization parameters (SPAT) accompanying the compressed signals (L, R). The Decorrelation comprises applying a different phase shift to each subband of the input signal combined with addition of an overall delay. The invention makes it possible to improve the broadening in the binaural rendition of audio scenes initially in a multi-channel format.

主权项

1. A method of processing sound data for a three-dimensional spatialized restitution on two restitution channels for the respective ears of a listener, the sound data being initially in a multi-channel format and then compression-encoded on a reduced number of channels,
said multi-channel format consisting in providing more than two channels able to feed respective loud speakers, the method comprising the steps:
obtaining spatialization parameters with the compressed data on said reduced number of channels,for each restitution channel associated with an ear of the listener, forming, on the basis of said spatialization parameters, a combination of filters each representing transfer functions between that ear of the listener and loud speakers that could be fed by respective channels of the initial multi-channel format,said combination comprising at least one first grouping, forming a first filter, on the basis of the transfer function of a front loud speaker, the transfer function of a back loud speaker, and a version of the transfer function of the back loud speaker, representing a decorrelation between channels, and wherein the front and back loud speakers are situated on a same first side with respect to the listener, andapplying the combination of filters associated with each restitution channel to the compressed data,wherein the method furthermore comprises the steps:
for each restitution channel associated with an ear of the listener, determining from said spatialization parameters at least one transfer function of a loud speaker behind the listener's ear and representing a decorrelation between the channels of the multi-channel format respectively associated with the back loud speaker and at least one loudspeaker-in front of the listener's ear, said decorrelation comprising applying to a signal input to the transfer function representing a decorrelation and broken down into frequency subbands a different phase shift in each of the subbands, combined with the addition of an overall delay to the signal, and for each restitution channel, integrating said transfer function representing a decorrelation in said combination of filters associated with this restitution channel.