A fast H.264-based picture-in-picture (PIP) transcoder

The work presents a novel and fast transcoding scheme with PIP (picture-in-picture) functionality, based on the H.264/AVC standard. We seamlessly achieve significant speedup and maintain identical video quality for the composite video content using two H.264 bitstreams. The proposed partial re-encoding transcoder (PRET) method, based on the intra-prediction refinement, inter-prediction refinement and rate-distortion optimization, has sped up by 8 times compared with rate-distortion (R-D) based optimization alone. In addition, the performance of the PRET is better than that of the R-D re-encoding algorithm.