在低码率信道中提高视频编码质量的方法

Enhancement of Video Coding Quality in Low Bit Rate Channel

电视手机是未来几年数字视频应用的一个热点.该文探讨适合于中低码率无线信道应用的一种方法:在实时编码的初期,通过量化QP(quantization parameter)值的调整,来满足信道带宽的要求;当信道变差时,在编码端采取动态丢帧策略,通过场景切换检测,将相关性强的帧丢失,在解码端通过双线性时序插补方法,恢复丢失的帧.这样可在保证编码质量的前提下,满足无线信道带宽时变的要求.同时讨论将这种方法应用到AVS和H.264视频编码算法中,实验证明这种方法可以有效应用到未来的电视手机中.

Mobile phones capable of receiving TV programs are expected to appear in the market. This paper discusses a method for enhancing video coding quality in a low bit rate channel aimed at mobile TV applications. In the early stage, quantization parameter （QP） is adjusted to make the video stream fit the bandwidth. When network jam occurs, the bandwidth decreases. A dynamic frame discard strategy is proposed at the encoder is proposed, which discards the frames correlated to others based on scene change detection, and uses bilinear temporal interpolation to estimate the missing frames in the decoder. We obtain better video quality to meet requirements of the wireless channel bandwidth. Experiments show effectiveness of the method.