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Spiteri and Sitaraman Honored for Work on Improving Video Quality

Kevin Spiteri (l.) and Ramesh Sitaraman (r.)
Kevin Spiteri (l.) and Ramesh Sitaraman (r.)

College of Information and Computer Sciences researchers from the Laboratory for Internet-Scale Distributed Systems (LIDS), PhD student Kevin Spiteri and Professor Ramesh Sitaraman, received the Excellence in DASH Award at last week's Association for Computing Machinery Multimedia Systems Conference for their paper, "From Theory to Practice: Improving Bitrate Adaptation in the DASH Reference Player," co-authored with Daniel Sparacio of CBS interactive.

The Excellence in DASH Award is presented by the DASH Industry Forum (DASH-IF) each year. DASH-IF is a consortium of major enterprises in the video ecosystem, including Microsoft, Google, Verizon, Netflix, Comcast, Cisco, Akamai, Intel, Samsung, LG, Huawei, and others.  

According to Sitarman, online video, whether streamed on Netflix, YouTube, or news sites like CNN, constitutes nearly 75% of all Internet traffic. As anyone who watches video on these or other services knows, stalled or low-quality video can be annoying and can significantly affect the enjoyment or utility of watching a favorite show, news clip, or how-to video.

The award-winning paper proposes a solution to video-quality problems, presenting three algorithms, BOLA-E, DYNAMIC, and FAST SWITCHING, used inside video players. These algorithms enable the video player to play with fewer stalls (rebuffers) and play at a higher quality (bitrates). Further, they reduce the video quality switches during playback and respond more quickly to connectivity changes.

DASH (Dynamic Adaptive Streaming over HTTP) is the open standard for online video streaming on the Internet.  Notably, the three algorithms proposed in the paper are now part of the DASH video reference player standard. "This is important," says Sitaraman, "since video providers often implement their own video players by using  the algorithms in the reference standard." The proposed algorithms are now already successfully deployed in production by major video providers such as BBC, CBS, Orange, and several others who use the reference standard.

The BOLA-E and DYNAMIC algorithms use Lyapunov control theory to set the bitrate of the video to maximize video quality and minimize re-buffering. The FAST SWITCHING algorithm opportunistically replaces low-quality video segments in the video player's buffer with higher quality ones, before they can be rendered to the user. As its name suggests, FAST SWITCHING allows the video playback to switch to higher quality more quickly when your network connection improves.