Distortion optimized bandwidth allocation on cluster of Video-on-Command servers

An optimal bandwidth allocation scheme for cluster video on command (VOD) servers system is introduced in the paper. An analytic model of video distortion and server nodepsilas bandwidth limitation is proposed. The bandwidth allocation is considered as an optimization problem with the constraints of video quality and link capacity. The bandwidth occupation is dynamically adjusted according to observed available bit rate (ABR) and round-trip time (RTT). Compared with TCP additive increase multiplicative decrease (AIMD) scheme, the proposed scheme benefits from lowering bandwidth cost while network degradation is detected and hereby avoids network congestion, and can reduce the average packet loss ratio from 17% to 1.8% while improving the video quality 3.5 dB in PSNR.