A novel frame skipping method in transcoder, with motion information, buffer fullness and scene change consideration

Frame-skipping is basis for reducing output bit rate in real time transcoding over bandwidth-constrained channels, keeping buffer conditions under control. One approach consists in skipping frames whenever encoder buffer is going to overflow: the drawback is that high motion and scene change frames too might be skipped, incurring in visual artifacts and average compression reduction. Another method is to track motion changes occurrences and to skip low motion complex frames, to maximize output quality of encoded high motion frames. Nevertheless, in low bandwidth channels, high motion frames encoding requires more bits than average. So this approach does not always conform to buffer compliancy. In this paper, we propose a combination of these two fundamental approaches. It monitors buffer fullness in frame by frame manner and also concerns about quality encoding of scene change and high motion frames. Experimental results show that it can produce high quality output even in very low target bit rate transcoding.