Improved H.264/AVC lossless intra compression using multiple partition prediction for 4×4 intra block
The sample by sample DPCM (SbS DPCM) is an important prediction technique for the H.264/AVC lossless intra compression. In this paper, we propose a new prediction method that is more efficient than the conventional SbS DPCM, thereby improving the overall compression performance. The proposed method prepares 5 partition patterns for each 4×4 block such as 4×4 (no partition), 4×2, 2×4, 2×2 and 1×1. The pixels in each partition is intra predicted by SbS DPCM and the best partition which produces minimum bit is selected as the partition pattern for the 4×4 block. Also, the number of available intra prediction directions is determined according to the partition pattern to avoid too much side-information transmission. The experimental results show that the proposed method gives 3.62 % point bit rate saving on average and 4.74 % point bit rate saving at maximum compared to the conventional SbS DPCM.