Bitstream syntax for multi-process audio decoding
First Claim
1. A method of decoding a compressed audio bitstream containing syntax elements conforming to a bitstream syntax to produce at least one audio signal, the bitstream syntax defining a base coding layer and a frequency extension coding layer that codes a portion of audio content using a frequency extension coding, the method comprising:
- with a processor;
reading the frequency extension coding layer of the compressed audio bitstream;
parsing a plurality of syntax elements from the frequency extension coding layer specifying parameters used in the frequency extension coding, the parameters associated with different frequency sub-bands and including a number of sub-bands and at least one starting point associated with a change in a coding transform between frequency bands wherein the at least one starting point is identified based on an energy difference between the compressed audio bitstream and an original audio signal in a selected frequency band;
reconstructing the portion of the audio content;
by processing the coded audio content based on the starting point, wherein the processing includes changing a coding transform at the starting point so as to produce a corresponding audio signal; and
outputting the audio signal.
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Accused Products
Abstract
An audio decoder provides a combination of decoding components including components implementing base band decoding, spectral peak decoding, frequency extension decoding and channel extension decoding techniques. The audio decoder decodes a compressed bitstream structured by a bitstream syntax scheme to permit the various decoding components to extract the appropriate parameters for their respective decoding technique.
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Citations
18 Claims
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1. A method of decoding a compressed audio bitstream containing syntax elements conforming to a bitstream syntax to produce at least one audio signal, the bitstream syntax defining a base coding layer and a frequency extension coding layer that codes a portion of audio content using a frequency extension coding, the method comprising:
with a processor; reading the frequency extension coding layer of the compressed audio bitstream; parsing a plurality of syntax elements from the frequency extension coding layer specifying parameters used in the frequency extension coding, the parameters associated with different frequency sub-bands and including a number of sub-bands and at least one starting point associated with a change in a coding transform between frequency bands wherein the at least one starting point is identified based on an energy difference between the compressed audio bitstream and an original audio signal in a selected frequency band; reconstructing the portion of the audio content; by processing the coded audio content based on the starting point, wherein the processing includes changing a coding transform at the starting point so as to produce a corresponding audio signal; and outputting the audio signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. An audio decoder situated to receive a compressed audio bitstream containing syntax elements conforming to a bitstream syntax, the bitstream syntax defining a base coding layer and a frequency extension coding layer for coding at least a portion of the audio content using frequency extension coding, the audio decoder comprising:
a processor that parses the base coding layer and the frequency extension coding layer of the compressed audio bitstream to obtain a plurality of syntax elements from the frequency extension coding layer specifying parameters used in the frequency extension coding, the parameters associated with different frequency bands, a number of frequency sub-bands, and at least one starting point identified based on an energy difference between the compressed audio bitstream and an original audio signal in a selected frequency band and associated with a change in a coding transform between frequency bands, wherein the processor reconstructs the portion of audio content to produce an output audio signal based on changing a coding transform at the at least one starting point. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of decoding a compressed audio bitstream, comprising:
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at a processor, receiving syntax elements conforming to a bitstream syntax to produce at least one audio signal, the bitstream syntax defining a base coding layer, a channel extension coding layer, and a frequency extension coding layer that codes a portion of audio content using a frequency extension coding and a channel extension coding layer; with the processor, reading the base coding layer and the frequency extension coding layer of the compressed audio bitstream and parsing a plurality of syntax elements from the frequency extension coding layer specifying parameters used in the frequency extension coding, the parameters associated with different frequency sub-bands and including a number of sub-bands and a starting point associated with a change in a coding transform, band configuration parameters specifying spectral band locations where frequency extension coding is applied with a different transform window size than the base coding; and reconstructing the portion of the audio content by processing the coded audio content based on the starting point, the sub-bands, and the band configuration parameters by changing a coding transform at the starting point to produce a corresponding audio output signal.
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Specification