Quantization matrices based on critical band pattern information for digital audio wherein quantization bands differ from critical bands
First Claim
1. In an audio encoder, a method comprising:
- processing a group of frequency coefficients as critical bands according to an auditory model to generate an excitation pattern; and
computing a quantization matrix directly from and in proportion to the excitation pattern, the quantization matrix including weights for quantization bands that partition the group, wherein the quantization bands differ from the critical bands.
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Abstract
Quantization matrices facilitate digital audio encoding and decoding. An audio encoder generates and compresses quantization matrices; an audio decoder decompresses and applies the quantization matrices. The invention includes several techniques and tools, which can be used in combination or separately. For example, the audio encoder can generate quantization matrices from critical band patterns for blocks of audio data. The encoder can compute the quantization matrices directly from the critical band patterns, which can be computed from the same audio data that is being compressed. The audio encoder/decoder can use different modes for generating/applying quantization matrices depending on the coding channel mode of multi-channel audio data. The audio encoder/decoder can use different compression/decompression modes for the quantization matrices, including a parametric compression/decompression mode.
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Citations
23 Claims
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1. In an audio encoder, a method comprising:
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processing a group of frequency coefficients as critical bands according to an auditory model to generate an excitation pattern; and
computing a quantization matrix directly from and in proportion to the excitation pattern, the quantization matrix including weights for quantization bands that partition the group, wherein the quantization bands differ from the critical bands. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A computer-readable medium encoded with computer-executable instructions for causing a computer programmed thereby to perform a method comprising:
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receiving a group of frequency coefficients;
processing the group of frequency coefficients as plural critical bands according to a model of human auditory perception to generate pattern information for the group of frequency coefficients;
generating a quantization matrix for the group of frequency coefficients based at least in part upon the pattern information for the group of frequency coefficients, the quantization matrix including plural quantization bands partitioning the group of frequency coefficients, each of the plural quantization bands having a weight in the quantization matrix, wherein the plural quantization bands are different than the plural critical bands; and
applying the quantization matrix to the group of frequency coefficients. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. An audio encoder comprising:
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a modeler for processing audio data according to a model of human auditory perception and for generating pattern information for the audio data, wherein each of plural critical bands spectrally partitions the audio data in the model of human auditory perception; and
a program module for computing a set of plural weighting factors from and in proportion to the pattern information for the audio data, wherein each of the set of plural weighting factors comprises a weight for a different one of plural quantization bands that spectrally partition the audio data, wherein the quantization bands are different than the critical bands. - View Dependent Claims (19, 20, 21, 22, 23)
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Specification