Mixing and playback of JPEG compressed packet videos

Video mixing, which is the simultaneous display of multiple motion videos received from multiple independent sources across a packet switched network, is addressed. A straightforward approach, which performs mixing at the pixel level, is analyzed and found undesirable because of the requirements of large amount of expensive memory and decompression capacity. A technique that performs direct mixing of JPEG compressed data is introduced. An efficient structure based on this technique, which needs only a frame worth of buffering and decompression regardless of the number of video windows and their sizes, is presented. Packet video playback is discussed, and two simple heuristics are proposed