A new approach to decoding and compositing motion-compensated DCT-based images
A novel decoding algorithm for the MC-DCT (motion-compensation discrete-cosine-transform)-based video, which performs inverse MC before inverse DCT, is designed. This algorithm can be applied in compositing compressed video within the network, which may take multiple compressed video sources and combine them into a single compressed output stream. The proposed algorithm convers all MC-DCT compressed video into the DCT domain and performs compositing in the DCT domain. This DCT-domain approach can reduce the required computations with a speedup factor depending on the compression ratio and the nonzero motion vector percentage. However, dropping some least-significant DCT coefficients may be necessary for the worst case of high-motion video in real-time implementations. Some issues of networked video compositing are also discussed. Another direct application of the proposed decoding algorithm is converting MC-DCT compressed video to the DCT compressed format directly in the DCT domain.<<ETX>>