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Sitaraman Wins IEEE William Bennett Prize for Influential Work on Improving Video Stream Quality

Ramesh Sitaraman standing in front of the Computer Science building and an azalea bush with white flowers
Ramesh Sitaraman

Distinguished Professor Ramesh Sitaraman will receive the 2023 IEEE Communications Society William R. Bennett Prize with Kevin Spiteri ‘21PhD and Rahul Urgaonkar for their invention of BOLA, a widely-used adaptive bitrate (ABR) algorithm for video streaming. BOLA enables videos to play continuously at high quality without freezing and is currently used to enhance the viewing experience of hundreds of millions of users around the world.

Video streaming is indispensable to modern society and underlies internet applications such as teleconferencing, on-demand entertainment, and live sporting events. However, providing a high quality of experience for video users is a complex scientific challenge, as users prefer to view videos at the highest quality (bitrate) possible, but bitrates that are too high relative to available bandwidth can cause rebuffering (i.e., video freezing) during playback.

BOLA tackles this video stream quality challenge by dynamically adapting the video quality to match the current internet connectivity of the user’s device. BOLA uses sophisticated Lyapunov optimization techniques to modulate the bitrate and maximize video quality on an ongoing basis.

“If the internet connectivity of your mobile phone starts to degrade when you are playing a video, BOLA operating within your video player will sense that degradation and step down the quality to prevent the video from freezing,” says Sitaraman.

BOLA and its variants have had a profound impact on real-world video streaming. In collaboration with Akamai, BOLA has been implemented as a standard ABR algorithm in the MPEG-DASH reference video player, dash.js. MPEG-DASH is the open standard for video streaming on the internet and its reference video player is the basis for many video players implemented in academia and industry. Further, BOLA and its variants are widely used in commercial video streaming by major video providers such as Orange, BBC, and CBS. Recently, Amazon Prime Video deployed a variant of BOLA in its video players to enhance the quality of hundreds of millions of live and on-demand streams daily.

A fellow of the Association for Computing Machinery (ACM) and IEEE, Sitaraman is known for his pioneering work in content delivery networks and edge computing services that currently deliver much of the world’s web content, streaming videos, and edge applications. His recent quarter-century retrospective on the Networking Channel tells the story of the evolution of the edge, CDNs, and edge computing. He is a recipient of the inaugural ACM SIGCOMM Networking Systems Award for his work on the Akamai CDN, an Excellence in DASH Award for his work on ABR algorithms, and a UMass Amherst Distinguished Teaching Award.

The William R. Bennett Prize is granted annually by the IEEE Communications Society to recognize “quality, originality, utility, timeliness, [and] clarity of presentation” in original papers published in its venues in the previous three years.