在研究H.264帧内预测算法的基础上,提出一种新颖实用的自适应帧内预测快速算法.首先,利用前一帧和当前帧对应位置宏块的帧内预测模式进行预测,从而减少当前宏块的预测模式数量,降低编码复杂度;然后根据量化因子。自适应地插入使用各种帧内预测模式的修正帧,并改变候选预测块的数量来保证帧内预测快速算法的准确性.实验结果表明,在码率增加小于3%,恢复图像平均峰值信噪比下降不到0.04dB的情况下,使用帧内预测快速算法,编码速度可提高22%~35%,满足实时视频通信的要求.该算法与H.264标准兼容,可用于实际视频通信产品.
According to the intra prediction in H. 264/AVC, a novel self-adaptive fast algorithm for intra prediction is proposed. First, the computational complexity of intra prediction is decreased based on the spatial/temporal correlation of the video sequence. Then, by using the quantization parameter, we adaptively change two key parameters to guarantee the precision of the fast intra prediction method. Simulation results show that intra macroblock encoding of H. 264/AVC is obviously speeded up using the proposed technique. Furthermore, this algorithm is compatible with H. 264/AVC, and can be used in practice.