A video decoder having efficient implementation of reverse variable length decoding

摘要

The invention relates to a video decoder comprising:
- a header decoder (110) receiving an encoded bit stream (100);
- a variable length decoder (120) connected to the header decoder (110) and receiving therefrom header decoded data;
- a quantizer and compensator (130) connected to the variable length decoder (120) during backward decoding for performing inverse quantization, transformation and motion compensation of the variable length decoded data and
- an output buffer (140) connected to the quantizer and compensator (130) for storing complete decoded data;
wherein while backward decoding the variable length decoding, inverse quantization, transformation and motion compensation of said header decoded data is done consecutively to obtain complete decoded data till a first point in the backward direction such that said first point is either an error point or a point before an end point of the macroblock containing error detected in the forward direction thereby eliminating the use of intermediate buffer for storing variable length decoded data during backward decoding and reducing the number of computations.