Limelight Promises Sub-Second Live Video Latency Using WebRTC
With latency times of 30 seconds or more the bane of live sports publishers, CDN Limelight Networks has chosen an opportune moment to announce Limelight Realtime Streaming, a solution that it promises to bring sub-one second latency to the global delivery of live video.
Limelight's solution relies on WebRTC and its own global network of edge servers. Traditional HTTP live streaming breaks videos into 10-second chunks and uses 3 chunks as a buffer, Limelight product manager Heath Kerley explains. But Limelight has created a plug-in-free solution that avoids those obstacles.
"Limelight addressed these issues by using the open and scalable industry-standard WebRTC technology to deliver reliable, broadcast-quality, real-time video streaming using the UDP data transfer protocol, Kerley says. "UDP eliminates the protocol chattiness of HTTP, and there is no buffering, which addresses the most significant contributor of latency."
Its solution relies on adaptive bitrate streaming to avoid the need for buffering. If connectivity becomes a problem, the solution switches to a lower-quality stream.
Besides live sports, Limelight sees opportunities in online gambling, healthcare, and security.
While Limelight isn't the first vendor to claim to have solved live video latency, it's taking a different approach, and that could pay off.
"Other solutions to lower latency involve reducing the chunk size for HLS and DASH streaming. They reduce latency but you can’t achieve sub-second with any chunk steaming protocol," Kerley says. "Another option is the use of a relatively new protocol QUIC, which also uses UDP as described above. The problem with QUIC is it is not supported in popular browsers, and requires viewers to install a plug-in, which is unpopular."
Limelight is demonstrating Limelight Realtime Streaming at IBC. It will be commercially available as a standalone product in early Q4.
It's not a standard yet, but that will likely change. Here's a detailed look at the state of WebRTC, the project that could finally deliver instantaneous video streaming at scale.
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