On low-complexity video encoding through feedback

We consider the design of a low-complexity video encoder in a scenario where an unconstrained receiver can help the encoder reduce complexity by exploiting feedback. To aid us in making design choices, we propose a simple model for video data that captures key properties of the temporal correlation between video frames and the predictability of motion vectors. Our analysis identifies the strengths and weaknesses of previous approaches and motivates a hybrid approach in which the decoder sends motion information to reduce motion estimation workload, the encoder uses incremental distributed source coding on the blocks with poor motion estimates, and the decoder performs decoder motion search and requests additional bits when necessary. Under the model, our analysis shows that such a hybrid scheme outperforms prior approaches. Experimental results of comparable implementations indicate that the hybrid scheme, while not fully implemented, is very promising in practice.