Variable frame rate encoding via active frame-skipping
Many rate control algorithms focus on the adjustment of quantisation values to retain a certain buffer level, and arbitrary frame-skipping is often needed to keep the buffer from overflow at very low bit-rates. In this paper, an active frame-skipping scheme is proposed to optimise the balance between spatial and temporal quality. The occurrence of frame-skipping is jointly dependent on the temporal and spatial quality of the video, and on the fullness of the buffer. This helps to achieve a consistent spatial and temporal quality and to enhance the overall perceptual quality. Experimental results show that the new scheme is simple but very effective, with large average PSNR gains and consistently improved visual quality, and the improvement in perceptual quality is much significant than that in average PSNR's.