Coding-gain-based complexity control for H.264 video encoder

The allowable computational complexity of video encoding is limited in a power-constrained system. Different video frames are associated with different motions and contexts, and so are associated with different computational complexities if no complexity control is utilized. Variation in computational complexity leads to encoding delay jittering. Typically motion estimation (ME) consumes much more computational complexity than other encoding tools. This work proposes a practical complexity control method based on the complexity analysis of an H.264 video encoder to determine the coding gain of each encoding tool in the video encoder. Experiments performed on a programming optimized source code show that the computational complexity associated with each frame is well controlled below a given limit with very little R-D performance degradation under a reasonable constraint comparing to the unconstrained case.