移动无线互联网接入中视频编码率控制策略

Video coding rate control strategy for wireless mobile Internet access

建立了用于移动无线互联网接入的视频编码转换模型,提出了自适应运动矢量估值方法。将编码转换码率控制分为图像层控制和宏块层两级,首先在总体上对每帧图像的编码比特数进行预分配,然后采用小波变换系数来表征图像特征,为帧内不同特征的宏块选用不同的量化因子,提出了一种新的码率控制策略。模拟实验表明:该方法在视频图像质量没有明显失真的前提下,提高了视频编码转换速度;编码转换输出码流和编码转换缓冲区占用量较稳定,重建图像的信噪比得到了明显的改善。

A method of improved motion vector based on quantization errors in transcoding for wireless mobile Intemet access is proposed in this paper. The control strategy of transcoder buffer is also discussed, and the number of coding bits on the picture layer in the whole is preallocated, then different types of picture respectively are processed on the basis of frondose picture characteristics when each frame is coded. Finally optimal quantization parameter for every macroblock in a frame is selected. The simulation results show that this method can effectively speed up the transcoding without significant lose in quality. The output bit rate of the transcoder and the buffer fullness tend to be stabilized, and the peak signal-noise-ratio （PSNR） of the reconstructed picture is raised.