Achieving Re-Loss-Free Video Coding

A video coding system is desirable to be idempotent or re-loss-free (RLF) in multigeneration coding. This paper shows that H.264 coding may suffer severe re-loss during recompression in common encoding modes. The multigeneration coding flow of a general hybrid coding is analyzed and a sufficient condition is presented for an RLF hybrid coding system. There are four key mechanisms to achieve RLF coding: RLF transform and quantization, Preserving Q clipping, Preserving Q deblocking, and prediction mode and Q Identification. Finally, the paper describes some future work on RLF coding.