包丢失是影响Internet视频通信质量的一个重要问题,为此提出了一种新颖的抗包丢失的自适应刷新方法.该方法是通过估计接收端重建图象的失真,在发送端自适应地确定需要刷新的宏块的位置.模拟实验表明,该方法与已有的顺序刷新和随机刷新等方法相比,不仅峰值信噪比(PSNR)有明显提高(0.3～2.5dB),而且计算复杂度较低,有利于实时实现.

Because of buffer overflow or delay timeout, packet loss is very common in current internet data transmission. The situation is even worse for real time internet video communications. Due to the prediction property of most state of the art video coding methods, data loss in a single frame can also deteriorate several successive frames. Intra update is well known as an effective method to reduce this error propagation. In this paper, we propose a novel adaptive intra update method. Taking decoder error concealment into account, the distortion at the decoder can be precisely estimated at the encoder by using the Recursive Optimal Per-pixel Estimate (ROPE). Then, image regions with maximum distortion are intra updated. Thus the damaged image regions at the decoder can be recovered in time. Simulation results demonstrate that our method achieves substantial and consistent gains in PSNR(0. 3~2. 5dB) over the non-adaptive methods such as raster-order intra update and random intra update for different video coding rates and packet loss rates. The complexity of this method is also modest, and it can be easily incorporated into current video communication system while maintaining compatibility.