MPEG video compositing in the compressed domain
Compositing several MPEG video sources into a single displayed streams is important for advanced MPEG video applications such as advanced multimedia terminals and multi-point video conferencing. Compositing video directly in the compressed domain can reduce computational complexity by processing less data and avoiding the conversion process back and forth between the compressed and uncompressed data formats. We address the computational speedup of compositing MPEG video directly in the DCT domain, compared to the straightforward spatial domain approach. In this paper, we propose a new compositing algorithm for MPEG1 compressed video which converts compressed MPEG1 video to the DCT domain and enables video compositing in the DCT compressed domain. Typical compositing operations include overlapping, scaling, translation, filtering, etc. Simulations using picture-in-picture video compositing sequence are presented to quantify some performance factors concerned.