A two-layer characteristic-based rate control framework for low delay video transmission

In this paper, we present a two-layer rate control framework for low delay video transmission based on a characteristic-based rate-quantization (R-Q) model. Specifically, with the frame-layer characteristic-based R-Q model, we are able to figure out the most appropriate quantization parameter (QP) to maintain targeted end-to-end delay by jointly considering the current buffer status, network bandwidth and the variation of bit rate of the input video source. Next, in macroblock-layer (MB), a greed-based rate-distortion (R-D) refinement of MBs approach is proposed to efficiently utilize the remaining available bit rate in order to enhance visual quality as much as possible. The experiments show that our two-layer characteristic-based rate control framework can quickly smooth out the impact of varying bit rate of video source on the buffer, meet targeted buffer delay time well, and substantially enhance the quality of the perceived video with lower computational complexity.