Rate-distortion optimized coding mode selection for video coders

摘要

A new method for real time implementation of rate-distortion optimized coding mode selection is disclosed that can be efficiently applied to H- 263-compatible video codecs and other codecs of similar type. A normalized rate-distortion model is used to efficiently compute the rate and the distortion when encoding motion-compensated prediction error signals, instead of performing DCT, quantization and entropy- encoding. A fast algorithm is also disclosed that determines sub-optimal values of coding parameters such as the quantization parameter and the Lagrangian multiplier, &lgr;, for the trellis search. Very good rate control and picture quality are achieved, especially when the disclosed techniques are applied in very low bitrate video coding.