Very low rate DCT-based video coding using dynamic VQ

We introduce a low-complexity, high-performance DCT-based video coding algorithm that is designed for very low bit rates. The algorithm employs a fast statistical and rate-distortion-optimized motion estimation method with integer-pel accuracy. The searching is constrained to a small diamond-shaped area whose center is the statistical mean, which is obtained using a finite-state machine modeling method based on dynamic state vector quantization. The same modeling method is also employed for coding the motion vectors. A simple rate-distortion criterion is used for alternating between three modes of operation for each 8×8 block: motion-only coding, motion-compensated predictive coding, and intra coding. Experimental results indicate that the proposed algorithm can outperform current H.263-based video coders significantly at very low bit rates. But, more important is that our algorithm´s rate, distortion, and complexity can be easily controlled, a feature desired in many very low bit rate video communication applications due to power and mobility constraints