Fixed rate speech compression system and method
First Claim
1. A fixed rate speech compression system for processing a frame of a speech signal, the fixed rate speech compression system comprising:
- an encoder operable to encode u first part of the frame using common frame based encoding;
the common frame based encoding comprising pitch pre-processing to modify the waveform of the speech signal as a function of classification of the frame;
the encoder operable to select one of a first speech coding mode and a second speech coding mode to encode a second part of the frame, wherein the first speech coding mode uses less bits than the second speech coding mode to code a fixed codebook contribution, wherein the first speech coding mode uses a first vector quantizer to jointly code both an adaptive codebook gain and a fixed codebook gain, and wherein the second speech coding;
mode uses a second vector quantizer to code the adaptive codebook gain and a third vector quantizer to code the fixed codebook gain.
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Abstract
The invention improves the encoding and decoding of speech by focusing the encoding on the perceptually important characteristics of speech. The system analyzes selected features of an input speech signal, and first performing a common frame based speech coding of an input speech signal. The system then performs a speech coding based on either a first speech coding mode or a second speech coding mode. The selection of a mode is based on characteristics of the input speech signal. The first speech coding mode uses a first framing structure and the second speech coding mode uses a second framing structure.
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Citations
28 Claims
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1. A fixed rate speech compression system for processing a frame of a speech signal, the fixed rate speech compression system comprising:
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an encoder operable to encode u first part of the frame using common frame based encoding;
the common frame based encoding comprising pitch pre-processing to modify the waveform of the speech signal as a function of classification of the frame;
the encoder operable to select one of a first speech coding mode and a second speech coding mode to encode a second part of the frame, wherein the first speech coding mode uses less bits than the second speech coding mode to code a fixed codebook contribution, wherein the first speech coding mode uses a first vector quantizer to jointly code both an adaptive codebook gain and a fixed codebook gain, and wherein the second speech coding;
mode uses a second vector quantizer to code the adaptive codebook gain and a third vector quantizer to code the fixed codebook gain. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method of processing a frame of a speech signal with a fixed rate speech compression system, the method comprising:
encoding a first part of the frame with common frame based encoding, the common frame based encoding comprising;
classifying the frame;
pitch pre-processing to modify the waveform of the speech signal as a function of classification of the frame; and
selecting one of a first speech coding mode and a second speech coding mode to encode a second part of the frame, wherein the first speech coding mode uses less bits than the second speech coding mode to code a fixed codebook contribution, wherein the first speech coding mode uses a first vector quantizer to jointly code both an adaptive codebook gain and a fixed codebook gain, and wherein the second speech coding mode uses a second vector quantizer to code the adaptive codebook gain and a third vector quantizer to code the fixed codebook gain. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
Specification