Bitstream syntax for multi-process audio decoding
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.
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 channel extension coding layer for coding a portion of audio content using a channel extension coding, the method comprising:
with a processor, reading the base coding layer and channel extension coding layer of the compressed audio bitstream;
parsing a plurality of syntax elements from the channel extension coding layer specifying parameters used in the channel extension coding, the parameters associated with different frequency sub-bands and including a number of sub-bands, at least one band size multiplier, and a channel extension starting band; and
reconstructing the portion of the audio content and producing a corresponding audio output signal by processing the coded audio content of the channel extension coding layer.
2. The method of claim 1 wherein the parameters comprise reverb control parameters, which comprise a scaling of an effect signal, and filter tap at which the effect signal is generated.
3. The method of claim 1 wherein the parameters comprise channel correlation parameters, which comprise choice of left magnitude/right magnitude (LMRM) parameterization or normalized correlation matrix parameterization from which a channel correlation matrix is derived.
4. The method of claim 1 wherein the parameters are associated with control of an automatic scale adjustment.
5. The method of claim 1 wherein the parameters comprise a prediction type from among no prediction, prediction across time, and prediction across frequency.
6. The method of claim 1 wherein the parameters comprise a coded channel type from among sum and difference.
7. The method of claim 1 , further comprising playing the output audio signal.
8. An audio decoder, comprising:
a processor; and
a computer-readable medium coupled to the processor, the computer-readable medium having stored thereon processor-executable instructions for execution by the processor for an audio decoding method comprising:
receiving a compressed audio bitstream containing syntax elements conforming to a bitstream syntax, the bitstream syntax defining a base coding layer and a channel extension coding layer for coding a portion of audio content using a channel extension coding, the compressed audio bitstream including parameters comprising a band configuration parameterization, which comprises a number of bands, a size relation among bands, and a starting band of channel extension coding, and
reconstructing the portion of the audio content and producing a corresponding audio output signal by processing the coded audio content using the channel extension coding layer.
9. The audio decoder of claim 8 , wherein the audio decoding method associated with the processor-executable instructions further comprises:
reading the base coding layer and channel extension coding layer of the compressed audio bitstream; and
processing coded audio content of the channel extension coding layer to reconstruct the portion of audio content in an output audio signal.
10. The audio decoder of claim 8 , wherein the audio decoding method associated with the processor-executable instructions further comprises:
reading the base coding layer and channel extension coding layer of the compressed audio bitstream;
parsing a plurality of syntax elements from the channel extension coding layer specifying parameters used in the channel extension coding; and
processing coded audio content of the channel extension coding layer to reconstruct the portion of audio content in an output audio signal.
11. The audio decoder of claim 10 , wherein the parameters comprise reverb control parameters, which comprise a scaling of an effect signal and a filter tap at which the effect signal is generated.
12. The audio decoder of claim 10 , wherein the parameters comprise channel correlation parameters, which comprise choice of left mono/right mono (LMRM) parameterization or normalized correlation matrix parameterization from which a channel correlation matrix is derived.
13. The audio decoder of claim 10 , wherein the parameters are associated with control of an automatic scale adjustment.
14. The audio decoder of claim 10 , wherein the parameters comprise a prediction type from among no prediction, prediction across time, and prediction across frequency.
15. The audio decoder of claim 10 , wherein the parameters comprise a coded channel type from among sum and difference.
16. The audio decoder of claim 8 , further comprising a speaker coupled to the processor so as to play the output audio signal.
17. The audio decoder of claim 8 , wherein the audio decoding method associated with the processor-executable instructions further comprises:
reading the base coding layer and channel extension coding layer of the compressed audio bitstream;
parsing a plurality of syntax elements from the channel extension coding layer specifying parameters used in the channel extension coding; and
processing coded audio content of the channel extension coding layer to reconstruct the portion of audio content in an output audio signal based on the parsed plurality of syntax elements.
18. An audio decoder, comprising:
a processor; and
a computer-readable medium coupled to the processor, the computer readable medium having stored thereon processor-executable instructions for execution by the processor for an audio decoding method comprising:
receiving a compressed audio bitstream containing syntax elements conforming to a bitstream syntax, the bitstream syntax defining a base coding layer and a channel extension coding layer for coding a portion of audio content using a channel extension coding,
reading the base coding layer and channel extension coding layer of the compressed audio bitstream;
parsing a plurality of syntax elements from the channel extension coding layer specifying parameters used in the channel extension coding, wherein at least one of the plurality of syntax elements is associated with an identification of at least one tile as an anchor tile; and
reconstructing the portion of the audio content and producing a corresponding audio output signal by processing the coded audio content of the channel extension coding layer.