System and method for stereo digital audio compression with co-channel steering
First Claim
1. A method for encoding multiple channels of audio information comprisinggenerating at least one encoded channel numbering less than said multiple channels from said multiple channels;
- andgenerating a co-channel of volume steering information for each of said multiple channels from said multiple channels comprised ofat least one first co-channel and at least one second co-channel;
wherein each of said multiple channels comprisesat least one first channel and at least one second channel;
wherein the ratio of said first and second co-channels varies in relation to the ratio of the magnitude of said first and second channels; and
said magnitude of said first and second co-channels varies in relation to the correlation of said first and second channels.
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Abstract
Left right and surround components of a stereo signal are coded into a monaural and small co-channel providing volume steering for recreating a stereo effect with a substantially reduced bit rate. The signal is split into a sum and difference signal, the difference signal is randomized and the sum is added to the randomized difference to comprise the single audio channel. A functional relationship is solved for left and right volumes which is then transmitted for intervals on the co-channel. Decoding of the single transmission channel directs it to left, right, or surround channels based on decoding on the logic co-channel. The co-channel updates left and right volume levels which are interpolated through time to effect smooth volume change. Surround gain is determined from left and right channel gains to maintain unity total volume, with the sum of the squares of the three volume controls being unity.
53 Citations
25 Claims
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1. A method for encoding multiple channels of audio information comprising
generating at least one encoded channel numbering less than said multiple channels from said multiple channels; - and
generating a co-channel of volume steering information for each of said multiple channels from said multiple channels comprised of at least one first co-channel and at least one second co-channel; wherein each of said multiple channels comprises at least one first channel and at least one second channel; wherein the ratio of said first and second co-channels varies in relation to the ratio of the magnitude of said first and second channels; and said magnitude of said first and second co-channels varies in relation to the correlation of said first and second channels. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for encoding multiple channels of audio information comprising
means for generating at least one encoded channel numbering less than said multiple channels from said multiple channels; - and
means for generating a co-channel of volume steering information for each of said multiple channels from said multiple channels comprised of means for generating at least one first co-channel and at least one second co-channel; wherein of each said multiple channels comprises means for at least one first channel and at least one second channel; wherein the ratio of said first and second co-channels varies in relation to the ratio of the magnitude of said first and second channels; and said magnitude of said first and second co-channels varies in relation to the correlation of said first and second channels. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification