Patent ID: 7505825
Filing Date: 2009-03-17
Classification: G11B,H04S

Abstract:
1. A computer storage medium having stored thereon a data structure defining an aggregated data stream, said structure comprising: a first data field defining audio data having M channels to be specified in a first stream of the aggregated data stream; and a second data field specifying a header wherein the header includes metadata including a channel mask and specifying a continuously varying conversion function to be specified in a second stream of the aggregated data stream, said second stream being separate from the first stream, said conversion function being executed for converting the M channels of the audio data into N channels of data, wherein the N channels of data are dynamically determined upon the aggregated data stream being received at a destination device, wherein the conversion function is continuously adjustable depending on the destination device, wherein the conversion function includes a fold-down function specified by the metadata includes a plurality of coefficients which define a conversion of a Y audio data set having the M channels (Y wherein the audio data comprises a 5.1 audio stream having six channels having left front, right front, center, low frequency, left surround and right surround channels such that M=6, wherein the destination device comprises a stereo destination device having left and right channels such that N=2, wherein the coefficients include B, SMIX, CMIX and LFEMIX and wherein the fold-down function comprises: and wherein: L(N) is the data for the left channel of the stereo destination device; L(M) is the left front channel data of the 5.1 audio stream; LS(M) is the left surround channel data of the 5.1 audio stream; C(M) is the center channel data of the 5.1 audio stream; LFE(M) is the low frequency channel data of the 5.1 audio stream; R(N) is the data for the right channel of the stereo destination device; R(M) is the right front channel data of the 5.1 audio stream; and RS(M) is the right surround channel data of the 5.1 audio stream, wherein B=1/(1+SMIX+CMIX+LFEMIX) and wherein fold-down function is based on the following mix table wherein: wherein: W=20*65536*log X=20*65536*log Y=20*65536*log Z=20*65536*log -INFINITY represents negative infinity, and wherein the metadata includes the following string format representation for the mix table: W,-INFINITE,-INFINTE,W,Y,Y,Z,Z,X,-INFINITE,-INFINITE,X.