Weighted prediction in the H.264/MPEG AVC video coding standard

H.264/MPEG AVC is the first international video coding standard to include a weighted prediction (WP) tool, which is particularly useful for coding fades. In the H.264 WP tool, which is included in its main and extended profiles, a multiplicative weighting factor and an additive offset are applied to the motion compensated prediction. In explicit mode, a weighting factor and offset may be coded in the slice header for each allowable reference picture index. In implicit mode, the weighting factors are not coded but are derived based on the relative picture order count (POC) distances of the two reference pictures. In this paper, H.264´s standardization of the WP tool is described, and a non-normative method for calculating weighting factors is proposed. Experimental results are provided which measures the coding efficiency improvement using WP. When coding fade-to-black sequences, bitrate reductions of up to 67% were achieved.