Edge-based predictive scanning scheme of DCT coefficients for inter-frame video coding
Scanning of quantized transform coefficients is a very significant procedure in video coding. In H.264, it affects the coding efficiency of the following CABAC or CAVLC entropy coder directly. In this paper, we propose a novel edge-based predictive scanning scheme to improve the coding efficiency for inter-frame coding. This scheme includes three scanning pattern candidates. Besides zigzag pattern as defined in H.264, two alternative patterns are obtained by on-line training on frame level. Specifically, reference block is utilized to predict edge information in current 8×8 block. Based on predictive edge information, a suitable scanning pattern will be selected to scan the quantized coefficients of current 8×8 block. Since a similar prediction process can be done in the decoder side as well, no overhead is needed to be transmitted in the bit-stream. Experimental results show that the proposed edge-based predictive scanning scheme yields an average of 0.42% BD-bitrate reduction over the H.264 high profile.