Video quality equalization based on an estimated MOS using a very large-size buffer

Video quality encoded in a constant bitrate generally varies from scene to scene due to non-stationary nature of frame activity and motion. This paper thus proposes an equalization technique for video quality, where the bitrate for each scene is controlled to reduce the quality fluctuation over scenes. The equalization is performed on an estimation of the mean opinion score (EMOS) rather than PSNR which is not suitable for comparing video quality of different scenes. It is assumed that a large coding latency is acceptable to realize a bit budget trading over scenes, and that a very large-size buffer is available for reducing the bitrate fluctuation. Experimental results show that a buffer with a size of about 10 second is necessary to efficiently absorb the quality and bitrate fluctuations.