Quality and rate control strategy for digital audio
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.
91 Citations
111 Claims
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1-64. -64. (canceled)
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65. A computer-readable medium encoded with computer-executable instructions for causing a computer programmed thereby to perform a method comprising:
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selecting a quantization level within a range of quantization levels, wherein the selecting accounts for non-monotonicity of quality measure as a function of quantization level within the range; and
quantizing audio information by the quantization level. - View Dependent Claims (66, 67, 68, 69, 101)
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70. A computer-readable medium encoded with computer-executable instructions for causing a computer programmed thereby to perform a method comprising:
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quantizing audio information by a quantization level;
computing a first quality measure indicating quality of the audio information as quantized by the quantization level;
comparing the first quality measure to a second quality measure for the audio information, the second quality measure indicating quality of the audio information as quantized by a previous quantization level; and
if the comparing indicates non-monotonicity of quality measure as a function of quantization level, designating the quantization level as inferior. - View Dependent Claims (71, 72, 102)
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73. (canceled)
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74. In an audio encoder, a computer-implemented method comprising:
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determining a first quality measure associated with a first quantization level;
determining a second quality measure associated with a second quantization level;
determining a third quantization level within a quantization level range based upon location of a target quality on a trajectory of quality measure as a function of quantization level, wherein the first and second quantization levels define endpoints of the quantization level range, wherein the first and second quality measures define endpoints of the trajectory, and wherein the function relates logarithm of quality measure in proportion to inverse logarithm of quantization level. - View Dependent Claims (103, 104, 105, 106, 107, 108, 109, 111)
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75-100. -100. (canceled)
Specification