Three-dimensional wavelet-based scalable video compression
First Claim
1. A method of encoding an input video signal comprising a group of video frames for communication over a computer network, the method comprising the steps of:
- i) applying a two-level temporal decomposition using a wavelet to said group of frames to produce a plurality of temporal subbands;
ii) applying a spatial decomposition to each said temporal subband to produce a plurality of spatio-temporal subbands;
iii) quantizing the coefficients of said spatio-temporal subbands with a uniform scalar quantizer to produce a significance map; and
iv) run-length and adaptive arithmetic coding of said signal by a) encoding the significance map through a combination of run-length and adaptive arithmetic coding by;
A) coding run-length codewords using N-ary adaptive arithmetic coding, where N is the maximum run-length previously observed in coding the significance map; and
B) encoding the current run-length codeword using one of a specified plurality of probability models, the probability model being selected by a rule which selects a probability model according to the previous run-length codeword;
b) encoding the signs of all significant coefficients using the number of significant coefficients in a four pixel neighborhood as context; and
c) encoding the magnitudes of significant coefficients, in bit-plane order starting with the most significant bit-plane, using the number of significant coefficients in a four pixel neighborhood as context.
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Abstract
A method of encoding an input video signal for communication over a computer network, the method comprising the steps of: i) applying a three-dimensional wavelet-based temporal and spatial decomposition to produce a plurality of spatio-temporal subbands; ii) quantizing the coefficients of the spatio-temporal subbands with a uniform scalar quantizer to produce a significance map; and iii) ran-length and adaptive arithmetic coding of the signal by encoding the significance map, encoding the signs of all significant coefficients, and encoding the magnitudes of significant coefficients, in bit-plane order starting with the most significant bit-plane.
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Citations
15 Claims
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1. A method of encoding an input video signal comprising a group of video frames for communication over a computer network, the method comprising the steps of:
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i) applying a two-level temporal decomposition using a wavelet to said group of frames to produce a plurality of temporal subbands;
ii) applying a spatial decomposition to each said temporal subband to produce a plurality of spatio-temporal subbands;
iii) quantizing the coefficients of said spatio-temporal subbands with a uniform scalar quantizer to produce a significance map; and
iv) run-length and adaptive arithmetic coding of said signal by a) encoding the significance map through a combination of run-length and adaptive arithmetic coding by;
A) coding run-length codewords using N-ary adaptive arithmetic coding, where N is the maximum run-length previously observed in coding the significance map; and
B) encoding the current run-length codeword using one of a specified plurality of probability models, the probability model being selected by a rule which selects a probability model according to the previous run-length codeword;
b) encoding the signs of all significant coefficients using the number of significant coefficients in a four pixel neighborhood as context; and
c) encoding the magnitudes of significant coefficients, in bit-plane order starting with the most significant bit-plane, using the number of significant coefficients in a four pixel neighborhood as context. - View Dependent Claims (2, 3, 4, 5)
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6. A computer program product for encoding an input video signal comprising a group of video frames for communication over a computer network, said computer program product comprising:
i) a computer usable medium having computer readable program code means embodied in said medium for;
a) applying a two-level temporal decomposition using a wavelet to said group of frames to produce a plurality of temporal subbands;
b) applying a spatial decomposition to each said temporal subband to produce a plurality of spatio-temporal subbands;
c) quantizing the coefficients of said spatio-temporal subbands with a uniform scalar quantizer to produce a significance map; and
d) run-length and adaptive arithmetic coding of said signal by A) encoding the significance map through a combination of run-length and adaptive arithmetic coding by;
i) coding run-length codewords using N-ary adaptive arithmetic coding, where N is the maximum run-length previously observed in coding the significance map; and
ii) encoding the current run-length codeword using one of a specified plurality of probability models, the probability model being selected by a rule which selects a probability model according to the previous run-length codeword;
B) ending the signs of all significant coefficients using the number of significant coefficients in a four pixel neighborhood as context; and
C) encoding the magnitudes of significant coefficients, in bit-plane order starting with the most significant bit-plane, using the number of significant coefficients in a four pixel neighborhood as context. - View Dependent Claims (7, 8, 9, 10)
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11. An article comprising:
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i) a computer readable modulated carrier signal;
ii) means embedded in said signal for encoding an input video signal comprising a group of video frames for communication over a computer network, said means comprising means for;
a) applying a two-level temporal decomposition using a wavelet to said group of frames to produce a plurality of temporal subbands;
b) applying a spatial decomposition to each said temporal subband to produce a plurality of spatio-temporal subbands;
c) quantizing the coefficients of said spatio-temporal subbands with a uniform scalar quantizer to produce a significance map; and
d) run-length and adaptive arithmetic coding of said signal by;
A) encoding the significance map;
i) coding run-length codewords using N-ary adaptive arithmetic coding, where N is the maximum run-length previously observed in coding the significance map; and
ii) encoding the current run-length codeword using one of a specified plurality of probability models, the probability model being selected by a rule which selects a probability model according to the previous run-length codeword;
B) ending the signs of all significant coefficients using the number of significant coefficients in a four pixel neighborhood as context; and
C) encoding the magnitudes of significant coefficients, in bit-plane order starting with the most significant bit-plane, using the number of significant coefficients in a four pixel neighborhood as context. - View Dependent Claims (12, 13, 14, 15)
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Specification