Parallel variable length decoding with inverse quantization for software MPEG-2 decoders

Fast methods of variable length decoding (VLD) and inverse quantization (IQ) are proposed for software MPEG-2 video decoders. In these methods, microprocessors with SIMD type instructions execute VLD and IQ efficiently. The use of memory-efficient tables enables decoding multiple variable length codewords concurrently. In addition, the concurrently decoded data are inversely quantized in parallel by making full use of SIMD type instructions. Combining these two methods achieves 27-32% reduction of the clock cycles for VLD and IQ compared to a conventional method. The proposed methods are particularly effective for high bitrate streams.