Quality control quantization loop and bitrate control quantization loop for quality and rate control for digital audio
First Claim
1. A computer-readable storage medium encoded with computer-executable instructions for causing a computer programmed thereby to perform a method comprising:
- adjusting quantization of a block of frequency coefficients for audio information in a quality control quantization loop until satisfaction of one or more quality criteria; and
following and outside the quality control quantization loop, adjusting the quantization of the block in a bitrate control quantization loop until satisfaction of one or more bitrate criteria.
1 Assignment
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Accused Products
Abstract
An audio encoder regulates quality and bitrate with a control strategy. The strategy includes several features. First, an encoder regulates quantization using quality, minimum bit count, and maximum bit count parameters. Second, an encoder regulates quantization using a noise measure that indicates reliability of a complexity measure. Third, an encoder normalizes a control parameter value according to block size for a variable-size block. Fourth, an encoder uses a bit-count control loop de-linked from a quality control loop. Fifth, an encoder addresses non-monotonicity of quality measurement as a function of quantization level when selecting a quantization level. Sixth, an encoder uses particular interpolation rules to find a quantization level in a quality or bit-count control loop. Seventh, an encoder filters a control parameter value to smooth quality. Eighth, an encoder corrects model bias by adjusting a control parameter value in view of current buffer fullness.
123 Citations
20 Claims
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1. A computer-readable storage medium encoded with computer-executable instructions for causing a computer programmed thereby to perform a method comprising:
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adjusting quantization of a block of frequency coefficients for audio information in a quality control quantization loop until satisfaction of one or more quality criteria; and following and outside the quality control quantization loop, adjusting the quantization of the block in a bitrate control quantization loop until satisfaction of one or more bitrate criteria. - View Dependent Claims (2, 3, 4, 5)
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6. In an audio encoder, a computer-implemented method of controlling bitrate and audio quality, the method comprising:
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encoding audio information, wherein the encoding includes; in each of one or more iterations of a first quantization loop, quantizing the audio information; measuring audio quality; comparing the measured audio quality to one or more target quality parameters; in each of one or more iterations of a second quantization loop following and outside of the first quantization loop, measuring bit count of the audio information; and comparing the measured bit count to one or more target bit count parameters; and outputting the encoded audio information as part of an encoded audio bitstream. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13, 14)
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15. In an audio encoder, a computer-implemented method comprising:
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encoding audio information, wherein the encoding includes; in a quality control quantization loop iteration, selecting a first uniform, scalar quantization step size using a first set of rules and quantizing audio information using the first uniform, scalar quantization step size; in a bit-count control quantization loop iteration, selecting a second uniform, scalar quantization step size using a second set of rules and quantizing the audio information using the second uniform, scalar quantization step size, wherein the second set of rules is different than the first set of rules; and in each of one or more additional bit-count control quantization loop iterations, adjusting the second uniform, scalar quantization step size and re-quantizing the audio information; and outputting the encoded audio information as part of an encoded audio bitstream. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification