Patent ID: 6925120
Filing Date: 2005-08-02
Classification: H04N

Abstract:
1. A method for generating an output bitstream representing an input video having measurable rate and distortion characteristics, the output bitstream to be reconstructed as a constant quality output video, comprising: providing a base layer bitstream and an input enhancement layer bitstream representing the input video; generating a output enhancement layer bitstream having a variable bit-rate from the input enhancement layer bitstream according to the rate and distortion characteristics; combining the base layer bitstream with the output enhancement layer bitstream to form the output bitstream having a variable bit-rate and a constant distortion; measuring the rate and distortion characteristics as sample pairs from the base layer bitstream and the input enhancement layer bitstream comparing two adjacent rate and distortion sample pairs; averaging the measured distortion between the adjacent rate and distortion sample pairs to estimate a constant distortion value; determining maximum rate available to maintain constant distortion over available bandwidth of a channel; and adapting to variations in the rate samples over time using a sliding window of M frames.