Patent ID: 6931068

Claim:
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.