Real-time H.263+ frame rate control for low bit rate VBR video

H.263+ is an emerging video compression standard for the low bit rate visual communication. Most H.263+ rate control algorithms, e.g. the one used in the test model of the near-term (TMN), focus on macroblock level bit allocation and low latency by assuming a constant frame rate video encoding sent through a constant bit rate (CBR) channel. These algorithms cannot handle the fluctuation of the channel bandwidth well so that the transmitted video quality is degraded seriously. In this work, we propose a new H.263+ rate control scheme which supports the variable bit rate (VBR) channel through the frame rate adjustment. In particular, a fast realization of encoding frame rate control based on motion information within a sliding window is developed to efficiently determine the tradeoff between spatial and temporal qualities. Experimental results are provided to demonstrate the superior performance of the proposed scheme