Fast mode decision algorithm for inter-frame coding in H.264 extended Scalable Video Coding

In scalable video coding (SVC) standard, an exhaustive block mode search has been employed to determine the best coding mode for each macroblock (MB). This gives a high coding efficiency, however it causes very high computational complexity in encoding system. To reduce this complexity of the exhaustive mode search, we propose a fast mode determination algorithm for inter-frame coding based on correlative information between base layer and enhancement layers for providing coarse grain signal-to-noise ratio (CGS) scalability and spatial scalability. In the proposed algorithm, we use rate-distortion (RD) costs of BL_SKIP (base layer skip) and 16 times 16 modes, and mode information of a corresponding block of the base layer to finish inter-mode search procedure early in the neighboring enhancement layer. Also, an adaptive thresholding scheme is designed. We verify that the overall encoding time for all layers can be reduced up to 65% based on comparative analysis of experimental results with JSVM 9.12 reference software.