Error-Resilience Transcoding of H.264/AVC Compressed Videos

We propose an error resilience transcoder based on the intra refresh technique for H.264/AVC videos. Our algorithm focuses on making decisions on the number of inserted intra MBs, allocations of proper MBs for intra refresh, and the quantization parameter for each P-frame, according to varying channel condition and frame contents. We build source distortion, channel distortion, and bit-rate models for prediction and adopt the Lagrangian multiplier approach for constrained optimization. Existing algorithms are compared in experiments. The results show that our algorithm improves PSNR by 0.28~2.76 dB, compared to the "equal intra refresh" approach. Our algorithm also outperforms CBERC (Chen and Wang, 2001) by 0.1~1.13 dB, with the same number of inserted intra MBs, but different MB priorities in allocation