Post-Quantization Gain Correction in Audio Coding
First Claim
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1. A gain adjustment method in decoding an audio signal that has been encoded with separate gain and shape representations, said method comprising:
- estimating an accuracy measure of the shape representation for a frequency band of the audio signal, wherein the shape representation encodes a shape vector comprising coefficients of the audio signal for the frequency band, and wherein the shape vector has been encoded using a pulse vector coding scheme where pulses may be added on top of each other to form pulses of different height, and the accuracy measure is based on the number of pulses used for encoding the shape vector and a height of the maximum pulse in the shape representation;
determining, based on the estimated accuracy measure, a gain correction; and
adjusting the gain representation for the frequency band based on the determined gain correction.
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Abstract
A gain adjustment apparatus for use in decoding of audio that has been encoded with separate gain and shape representations includes an accuracy meter configured to estimate an accuracy measure of the shape representation, and to determine a gain correction based on the estimated accuracy measure. An envelope adjuster further included in the apparatus is configured to adjust the gain representation based on the determined gain correction.
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Citations
16 Claims
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1. A gain adjustment method in decoding an audio signal that has been encoded with separate gain and shape representations, said method comprising:
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estimating an accuracy measure of the shape representation for a frequency band of the audio signal, wherein the shape representation encodes a shape vector comprising coefficients of the audio signal for the frequency band, and wherein the shape vector has been encoded using a pulse vector coding scheme where pulses may be added on top of each other to form pulses of different height, and the accuracy measure is based on the number of pulses used for encoding the shape vector and a height of the maximum pulse in the shape representation; determining, based on the estimated accuracy measure, a gain correction; and adjusting the gain representation for the frequency band based on the determined gain correction. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A gain adjustment apparatus for use in decoding an audio signal that has been encoded with separate gain and shape representations, said apparatus comprising:
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a first digital processing circuit that is configured to estimate an accuracy measure of the shape representation for a frequency band of the audio signal, and to determine a gain correction based on the accuracy measure, wherein the shape representation encodes a shape vector comprising coefficients of the audio signal for the frequency band, and wherein the shape vector has been encoded using a pulse vector coding scheme where pulses may be added on top of each other to form pulses of different height, and the accuracy measure is based on the number of pulses used for encoding the shape vector and a height of the maximum pulse in the shape representation; and a second digital processing circuit that is configured to adjust the gain representation for the frequency band based on the determined gain correction. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16)
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Specification