Parallel intra coding for HEVC on CPU plus GPU platform
In High Efficiency Video Coding (HEVC), the intra coding performance is significantly improved due to the recursive splitting structure and up to 35 intra prediction modes. However, the computational complexity of intra coding increases largely as well. In this paper, a fast intra coding scheme is proposed based on CPU and GPU cooperation. Firstly, the intra prediction of variable blocks is performed in parallel on multi-cores GPU. Secondly, the intra prediction mode with minimum Sum of Absolute Difference (SAD) cost is selected and transmitted to the host CPU. Instead of exhaustively searching all the intra modes in Rough Mode Decision (RMD) process, the mode returned by the GPU is directly selected. Lastly, the texture gradient of each coding unit (CU) is assessed during parallel intra prediction, then used by the CPU for fast CU size decision. Experiment results show that the proposed parallel intra coding method achieves up to 62% complexity reduction with acceptable coding performance loss.