Post filter
First Claim
1. An audio decoder for decoding an audio bitstream generated by an audio encoder, the audio decoder comprising:
- a first decoding module adapted to operate in a first coding mode;
a second decoding module adapted to operate in a second coding mode, the second coding mode being different from the first coding mode; and
a pitch filter included in either the first coding mode or the second coding mode, the pitch filter adapted to filter a preliminary audio signal generated by the first decoding module or the second decoding module to obtain a filtered signal,wherein the pitch filter is selectively enabled or disabled based on a value of a first parameter encoded in the audio bitstream, the first parameter being distinct from a second parameter encoded in the audio bitstream, the second parameter specifying a current coding mode of the audio decoder and the pitch filter further de-emphasizes spectral valleys.
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Accused Products
Abstract
Disclosed is a method, apparatus and non-transitory computer readable storage medium, which is configured to examine an input audio signal to determine an estimated pitch period associated with a detection criterion, encode the filtered audio signal to generate a compressed audio bit stream, decode the compressed audio bit stream to generate a decoded audio signal and adaptively filtering the decoded audio signal to produce an output audio signal, wherein adaptively filtering the decoded audio signal comprises filtering each of a plurality of segments of the decoded audio signal in a manner that is dependent upon the estimated pitch period associated therewith, and wherein a pitch-based post-filter operates to shape noise components located between harmonics of the input audio signal.
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Citations
12 Claims
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1. An audio decoder for decoding an audio bitstream generated by an audio encoder, the audio decoder comprising:
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a first decoding module adapted to operate in a first coding mode; a second decoding module adapted to operate in a second coding mode, the second coding mode being different from the first coding mode; and a pitch filter included in either the first coding mode or the second coding mode, the pitch filter adapted to filter a preliminary audio signal generated by the first decoding module or the second decoding module to obtain a filtered signal, wherein the pitch filter is selectively enabled or disabled based on a value of a first parameter encoded in the audio bitstream, the first parameter being distinct from a second parameter encoded in the audio bitstream, the second parameter specifying a current coding mode of the audio decoder and the pitch filter further de-emphasizes spectral valleys. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification