Efficiency improvements in scalable audio coding
First Claim
1. An audio encoding method of coding audio signals into a layered data stream having a first layer and a second layer, said second layer serving as an enhancement of said first layer, the method comprisingforming an original digital audio signal,encoding said original signal to obtain a first layer signal,producing a residual signal to reflect a difference between the original signal and the first layer signal,evaluating the residual signal;
- and, in case the result of the evaluation meets given criteria,selecting a predetermined low-entropy signal to be encoded as a second layer signal, and, otherwise,selecting either said original signal or said residual signal to be encoded as said second layer signal, andproducing said second layer signal by encoding said selected signal.
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Abstract
An audio encoding method of coding audio signals into a layered data stream having a first layer and a second layer is presented. The second layer serves as an enhancement of the first layer. The method involves forming an original digital audio signal, encoding the original signal to obtain a first layer signal, producing a residual signal to reflect a difference between the original signal and the first layer signal, selecting either the original signal or the residual signal for encoding, and producing a second layer signal by encoding the selected signal. Moreover, the residual signal is evaluated and, in case the result of the evaluation meets given criteria, a predetermined low-entropy signal is selected to be encoded as the second layer signal, instead of the original signal or the residual signal.
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Citations
29 Claims
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1. An audio encoding method of coding audio signals into a layered data stream having a first layer and a second layer, said second layer serving as an enhancement of said first layer, the method comprising
forming an original digital audio signal, encoding said original signal to obtain a first layer signal, producing a residual signal to reflect a difference between the original signal and the first layer signal, evaluating the residual signal; - and, in case the result of the evaluation meets given criteria,
selecting a predetermined low-entropy signal to be encoded as a second layer signal, and, otherwise, selecting either said original signal or said residual signal to be encoded as said second layer signal, and producing said second layer signal by encoding said selected signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
- and, in case the result of the evaluation meets given criteria,
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19. An audio encoder for coding audio signals into a layered data stream having a first layer and a second layer, said second layer serving as an enhancement of said first layer, the encoder comprising:
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a first encoder element, capable of encoding an original digital audio signal into a first layer signal; a subtracting unit adapted to produce a residual signal to reflect a difference between the original signal and the first layer signal; a first selector adapted to select either said original signal or said residual signal for encoding as a second layer signal; a second encoder element, capable of producing said second layer signal by encoding said selected signal; an evaluating unit adapted to evaluate the residual signal and provide an indication that the result of the evaluation meets given criteria; and a second selector, said second selector being associated with said evaluating unit and being adapted, upon receiving said indication, to select, instead of said original signal or said residual signal, a predetermined low-entropy signal to be encoded by said second encoder element. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28, 29)
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Specification