【摘要】 编码模式的选择是视频编码器控制的一个重要功能,它直接决定了编码器的性能和效率。新的视频压缩协议H.264协议比其它视频压缩协议提出了更多的编码模式,这就决定了H.264编码器不能像H.263编码器一样,通过比较某个门限值来简单地决定采用哪种编码模式。另一方面,根据Rate-distortion理论,在失真度与比特率之间存在一个最佳折衷点。如果确定了合适的拉各朗日(Lagrangian)参数,就能利用拉各朗日公式找到这个最佳折衷点。把这一理论作为H.264编码器的模式选择算法,将会使H.264编码器根据图像内容自适应地选择最佳的编码模式,达到最佳的压缩效果。更多还原

【Abstract】 The choice of mode is the important function in video coder, which exerts a right influence on the performance and efficiency of video coders. H.264, a new advanced video compressed protocol, presents more modes than the other existed video compressed protocols, which means H.264 coders are not the same as H.263 coders that easily decide the adapted mode by comparing to some thresholds. On the other hand, according to rate-distortion theory, between distortions and rates there is the best tradeoff that can be found by lagrangian technique as long as a right lagrangian parameter is adopted. The application of the theory to the algorithm of mode decision in H.264 coders will make sure that H.264 coders can adapt themselves to the contents of different pictures to choose the best mode and attain the best performance.更多还原