Backward-Shifted Strategies Based on SVC for HTTP Adaptive Video Streaming
This addresses video streaming interruptions for users under variable network conditions, offering a novel method to enhance QoE.
The paper tackles the problem of video streaming interruptions due to TCP delays in HTTP adaptive streaming by proposing Backward-Shifted Coding (BSC), which adds time-shifted redundancy using Scalable Video Coding to pre-fetch future frames, resulting in high Quality of Experience with reduced buffering times and improved fluency.
Although HTTP-based video streaming can easily penetrate firewalls and profit from Web caches, the underlying TCP may introduce large delays in case of a sudden capacity loss. To avoid an interruption of the video stream in such cases we propose the Backward-Shifted Coding (BSC). Based on Scalable Video Coding (SVC), BSC adds a time-shifted layer of redundancy to the video stream such that future frames are downloaded at any instant. This pre-fetched content maintains a fluent video stream even under highly variant network conditions and leads to high Quality of Experience (QoE). We characterize this QoE gain by analyzing initial buffering time, re-buffering time and content resolution using the Ballot theorem. The probability generating functions of the playback interruption and of the initial buffering latency are provided in closed form. We further compute the quasi-stationary distribution of the video quality, in order to compute the average quality, as well as temporal variability in video quality. Employing these analytic results to optimize QoE shows interesting trade-offs and video streaming at outstanding fluency.