降低空间分辨率视频编码转换方法-《计算机技术与发展》

文章信息/Info

Author(s):: LI Xiao-hui; ZHU Liang; [1] School of Electronic Science and Technology, Anhui University[2]Anhui Television Station

Keywords:: video transcoding; reduced spatial resolution; self - adaptive intra - refresh; rate - distortion optimal rate control

摘要:: 根据漂移误差与帧间编码块的运动活动性的关系，提出了一种自适应帧内刷新方法。该方法根据目标比特率和实际比特率的差值，动态地调整阈值，从而有效地减少了帧内编码的比特率，保持了对差错的鲁棒性，限制了差错的时间传播。同时，根据率失真定理，在保证失真最小的情况下，为帧内不同的宏块选用最佳的量化系数。仿真结果表明：文中提出的方法有效地平滑了缓冲器的输出，同时峰值信噪比也有所提高

Abstract:: A self-adaptive intra-refresh scheme based on the relation between drift error and motion activity of intercoded blocks is proposed in this paper. The thresholds are dynamically adjusted according to the difference between the target bit rate and actual bit rate. This method can reduce the bit rate of intra coded frames while still maintating error robustness and limiting temporal propagation of errors. Besides, we present a new method for rate- distortion optimized coding mode selection. Using this method, we minimize distortion subject to the target rate constraint, and ohtain formulas that indicate how to choose the quantization parameters. The simulation results show that the buffer fullness tend to be stabilized and the PSNR of the reconstructed image is raised