We have been examining the transport of compressed video over rate-controlled networks, and have developed a smoothing and rate adaptation algorithm, called SAVE (Smoothed Adaptive Video over Explicit rate networks). SAVE attempts to preserve quality as much as possible, by exercising control over the source rate only when essential, when the delay at the source may exceed a bound. Understanding the impact on the quality of the video using rate adaptation is important and we begin to examine some quantitative measures of video quality in this context. For the form of source rate adaptation we advocate, it appears necessary to evolve the quality metrics typically used to evaluate the efficacy of mechanisms to transport video. We also attempt to understand the dynamic nature of the reduction in the encoded rate, since any prolonged impairment is likely to be noticeable. We study the sensitivity of SAVE to its parameters and network characteristics. Finally, the utility of a proposed scheme is measured by its ability to multiplex a large number of streams effectively. We demonstrate that by smoothing the demand from the source, SAVE helps achieve good multiplexing gains. We examine the effectiveness of SAVE across 20 different traces of entertainment videos using different compression algorithms.
We also note that in REF , video traces have been used for studying rate adaptation schemes that consider the quality of the rate-regulated videos.
Issues of Quality and Multiplexing when Smoothing Rate Adaptive Video
IEEE Transactions on Multimedia
Computer Science