Instruction-Level Optimization of H.264 Encoder Using SIMD Instructions

The latest video coding standard H.264/AVC is promising for its high coding performance with the cost of significantly higher complexity. In this paper, instruction-level optimization of H.264 encoder is proposed by exploiting single-instruction-multiple-data (SIMD) instructions. The key modules in H.264 encoder, such as SAD calculation, integer transform and inverse integer transform, SATD calculation and 1/4 pixel interpolation, are speed up. The simulation results on several video sequences show that our proposed instruction-level optimization achieves a speed-up factor of 1.3 up to 12 for every key module. The overall encoder speed-up gain is about twice without introducing serious quality degradation. The proposed instruction-level optimization is joined with algorithm optimization for X.264 encoder, and real-time encoding is achieved for video sequences in 4CIF format