SIMD-PROCESSOR-FRIENDLY MPEG-2 INTRA-QUANTIZER

A method and apparatus for performing quantization during video compression, such as within an MPEG-2 encoder. Intra-quantization is particularly described, although the teachings may be applied to inter-quantization as well. Computationally intensive portions of the quantization process are split into multiple components in response to differing execution probability. A first component is executed within each quantization iteration, and preferably is performed in parallel, such as using SIMD processing. At least one additional component, such as a second component, is serially processed in response to detecting a condition that does not arise with each loop iteration. One configuration replaces division operations with a combination of multiply and shift operations, while making extended use of table lookup procedures to reduce processing overhead.