Statistical multiplexing of variable-bit-rate videos streamed to mobile devices
ACM Transactions on Multimedia Computing, Communications, and Applications (TOMCCAP)
Consistent-degradation macroblock grouping for parallel video streams over DiffServ networks
Computer Communications
LMM-based frame-level rate control for H.264/AVC high-definition video coding
Image Communication
Control of distributed servers for quality-fair delivery of multiple video streams
Proceedings of the 20th ACM international conference on Multimedia
Rate control for consistent visual quality of H.264/AVC encoding
Image Communication
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The H.264 video coding standard achieves significantly improved video compression efficiency and finds important applications in digital video broadcast. To enable H.264 video encoding for digital TV broadcast and maximize its broadcast efficiency, there are two important issues that need to be adequately addressed. First, we need to understand the complex coding mechanism of an H.264 video encoder and develop a model to analyze and control its rate-distortion (R-D) behavior in an accurate and robust manner. Second, the R-D behaviors of individual channels in the broadcast system should be jointly controlled and optimized under bandwidth and buffer constraints so as to maximize the overall broadcast quality. In this paper, we develop a linear rate model and a linear rate control scheme for H.264 video coding. We develop an optimum statistical multiplexing system to allocate bits across video programs (each being encoded by an H.264 encoder) and video frames so that the overall video broadcast quality is maximized. We study the bandwidth and buffer constraints in video broadcast and formulate the optimum statistical multiplexing into a constrained mathematical optimization problem. Realizing that it is impossible to find a close-form solution for global optima, we propose a simple yet efficient algorithm to find a near-optimum solution for joint rate allocation under buffer constraints. Our extensive simulation results demonstrate that the proposed statistical multiplexing system achieves about 40-50% saving in bandwidth, provides a smooth video quality change across programs and frames, and maintains robust decoder buffer control.