Video quality by controlling inter frame encoding according to frame position in gop

Abstract

In some embodiments, a video encoding method includes controlling a set of block encoding modes in a plurality of inter video frames in a group of pictures (GOP) according to a frame position in the group of pictures, to generally decrease a forward inter-encoded frame content with the frame position in the group of pictures. An encoding mode determination is made for inter-frame encoding blocks (e.g. macroblocks) according to the frame position in the group of pictures. The determination may include forcing a block encoding mode to an intra, backward inter-predicted, or backward strong-weighted bi-predicted mode. The determination may be performed according to a frame type (P/B), frame position in GOP, frame content, a selected temporal and spatial pattern, a bit cost of making an encoding mode decision, and an available bit rate. The fraction of mode-forced blocks is generally increased as the GOP frame position advances.