A Two-Piece R-D Model for Hybrid Video Coding and Its Application in Fast Mode Decision

The mode decision process has a significant effect on the quality and complexity of a video encoder. The conventional method that fully codes each macro block for different modes results in the best quality performance, but it suffers from high computational complexity. On the other hand, some other methods ignore the residual part and use the prediction data, or adopt early mode selection approaches in order to reduce the computational cost. These approaches have a negative impact on the coding performance. In this paper, we have used a simple model for the residual coding part and proposed a two-piece R-D model for a macro block. Based on this model, we have introduced a mode decision algorithm that reduces the bit-rate by up to 11.62% at the expense of just 0.5% computational overhead.