Method and apparatus for decoding encoded groups of pictures of a video sequence and presenting said video sequence and said groups of pictures in temporally backward direction

摘要

MPEG video uses motion compensated prediction for coding pictures. A GOP includes at least one intra-coded picture to start decoding with and a number of inter-coded pictures and normally also includes bi-directionally predicted pictures. However, the GOP structure is not constructed for playing GOPs in backward direction in a trickplay mode across GOP boarders. The invention facilitates, for different GOP structures, a smooth backward video mode thereby reducing the required number of frame buffers and achieving near real-time speed presentation. In some embodiments some I and/or P pictures are decoded more than once. The invention also allows backwards decoding of MPEG-4-AVC GOPs including B-stored pictures.