Filtering of control parameters in 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:
- computing a value of a control parameter;
filtering the value as part of a sequence of previously computed values of the control parameter; and
estimating complexity of a current block of audio information, wherein the filtered value of the control parameter affects the estimating and thereby regulates at least in part quantization of the current block of audio information.
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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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computing a value of a control parameter; filtering the value as part of a sequence of previously computed values of the control parameter; and estimating complexity of a current block of audio information, wherein the filtered value of the control parameter affects the estimating and thereby regulates at least in part quantization of the current block of audio information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An audio encoder comprising:
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means for computing a value of a control parameter for audio information; a filter for lowpass filtering the value as part of a sequence of previously computed values for the control parameter; means for setting a target quality parameter based at least in part on the filtered value of the control parameter; and a quantizer for quantizing the audio information, wherein the filtered value of the control parameter at least in part regulates the quantizer. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A method comprising:
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computing a value of a control parameter; filtering the value as part of a sequence of previously computed values of the control parameter; and setting a target quality parameter for a current block of audio information, wherein the filtered value of the control parameter affects the setting of the target quality parameter and thereby regulates at least in part quantization of the current block of audio information. - View Dependent Claims (17, 18, 19, 20)
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Specification