Parallel fast inter mode decision for H.264/AVC encoding

•One hardware friendly parallel fast inter mode decision algorithm is proposed for H.264/AVC encoding.•Motion estimation for different block sizes are conducted in parallel.•Simplified distortion and bitrate estimation methods are used for efficient hardware implementation.•Dependencies among coding units are removed for parallel processing.•The coding cost of each mode can be obtained simultaneously.

For H.264/AVC encoding, the mode selection process consumes a large proportion of the overall computation. To reduce this burden, various fast mode decision algorithms have been proposed. The current fast mode decision algorithms usually exploit the relationship among the coding modes and use the context-based approach to reduce the number of modes to be checked for both intra coding and inter coding. The parallel capacity of hardware architectures are also taken into consideration. However, almost all the parallel fast mode decision designs are focusing on intra coding. In this paper, a hardware friendly parallel fast inter mode decision method is proposed. With the proposed method, the inter mode decision can be conducted efficiently in one pass and significant encoding speedup can be achieved with negligible coding efficiency loss. Moreover, the proposed method can be easily mapped to hardware architecture which can be used for the real-time video encoding.