Methods and systems for celp-based speech coding with fine grain scalability
First Claim
1. A method of encoding a speech signal in a code excited linear prediction (CELP)-based speech processing system that includes an adaptive codebook and a fixed codebook, wherein the speech signal is divided into frames and each frame is further divided into sequential sub-frames, the method comprising:
- generating linear prediction coding (LPC) coefficients for a frame;
generating pitch-related information by using the adaptive codebook, for each sub-frame of the frame;
generating pulse-related information by using the fixed codebook, for a first sub-frame of the frame and for a second sub-frame of the frame;
generating a basic bit-stream from the LPC coefficients, the pitch-related information, and the pulse-related information for the first sub-frame; and
generating enhancement bits from the pulse-related information for the second sub-frame.
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Abstract
Methods and systems for providing a CELP-based speech coding with fine grain scalability include a parameter encoder that generates a basic bit-stream from LPC coefficients for a frame, pitch-related information for all the sub-frames obtained by searching an adaptive codebook, and first pulse-related information for even sub-frames obtained by searching an fixed codebook. The parameter encoder also generates enhancement bits, which are preceded by the basic bit-stream, from second pulse-related information for odd sub-frames. The quality of synthesized speech is improved on a basis of one additional odd sub-frame pulse, as more of the second pulse-related information in the enhancement bits is received by a decoder.
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Citations
19 Claims
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1. A method of encoding a speech signal in a code excited linear prediction (CELP)-based speech processing system that includes an adaptive codebook and a fixed codebook, wherein the speech signal is divided into frames and each frame is further divided into sequential sub-frames, the method comprising:
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generating linear prediction coding (LPC) coefficients for a frame;
generating pitch-related information by using the adaptive codebook, for each sub-frame of the frame;
generating pulse-related information by using the fixed codebook, for a first sub-frame of the frame and for a second sub-frame of the frame;
generating a basic bit-stream from the LPC coefficients, the pitch-related information, and the pulse-related information for the first sub-frame; and
generating enhancement bits from the pulse-related information for the second sub-frame. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of synthesizing speech in a code excited linear prediction (CELP)-based speech processing system that includes an adaptive codebook and a fixed codebook, wherein a speech signal is divided into frames and each frame is further divided into sub-frames, the method comprising:
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receiving a basic bit-stream which includes linear prediction coding (LPC) coefficients for a frame, pitch-related information for all sub-frames of the frame, and first pulse-related information for a part of the sub-frames;
receiving enhancement bits which include a part or a whole of second pulse-related information for a remainder of the sub-frames;
generating an excitation by referring to the adaptive codebook and the fixed codebook based on the pitch-related information included in the basic bit-stream and the first pulse-related information included in the basic bit-stream, respectively;
generating an excitation by referring to the adaptive codebook and the fixed codebook based on the pitch-related information included in the basic bit-stream and the part or the whole of the second pulse-related information included in the enhancement bits, respectively; and
outputting synthesized speech according to the excitations and the LPC coefficients. - View Dependent Claims (10, 11, 12, 14, 15, 16, 18, 19)
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13. A speech processing system based on code excited linear prediction (CELP) for encoding a speech signal, wherein the speech signal is divided into frames and each frame is further divided into sub-frames, the system comprising:
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a generator of linear prediction coding (LPC) coefficients for a frame;
a first portion including an adaptive codebook for generating pitch-related information for each sub-frame of the frame;
a second portion including a fixed codebook for generating pulse-related information for each sub-frame of the frame, the pulse-related information including first information for a first kind of sub-frame and second information for a second kind of sub-frame; and
a parameter encoder for generating a basic bit-stream from the LPC coefficients, the pitch-related information, and the first pulse-related information, and for generating enhancement bits from the second pulse-related information.
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17. A speech processing system based on code excited linear prediction (CELP) for synthesizing speech, wherein a speech signal is divided into frames and each frame is further divided into sub-frames, the system comprising:
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a parameter decoder for extracting linear prediction coding (LPC) coefficients for a frame, pitch-related information for all the sub-frames of the frame, and first pulse-related information for a part of the sub-frames, from a basic bit-stream received, and for extracting a part or a whole of second pulse-related information for a remainder of the sub-frames from enhancement bits received;
a first portion including an adaptive codebook for generating an excitation based on the pitch-related information;
a second portion including a fixed codebook for generating an excitation based on the first pulse-related information or based on the part or the whole of the second pulse-related information; and
a synthesizer for outputting synthesized speech according to the excitations and the LPC coefficients.
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Specification