One of the hottest topics in video is reducing the delay or latency of live video streaming to viewers. As consumers increasingly go online to watch live sporting events and enjoy live video gaming, delivering the lowest-latency live streaming experiences is critical for content distributors, especially media organizations that have started exploring digital broadcast offerings for their viewers/listeners. Low-latency streaming is essential for keeping customers satisfied and maximizing revenue.
Imagine watching sports on a mobile screen and receiving social media texts from a friend watching the live broadcast celebrating a score that you haven’t seen happen yet. Or playing an online video game and the target of a shot you’re taking has actually already moved. Something needs to change to retain viewers’ attention. The two most popular formats for delivery to mobile devices, laptops, and streaming devices connected to TVs, are:
- HTTP Live Streaming (HLS)
- Dynamic Adaptive Streaming over HTTP (MPEG DASH)
These are Hypertext Transfer Protocol (HTTP)-based media streaming communications protocols that stream chunks of data over IP (Internet Protocol). The typical latencies delivering HLS or DASH range between 30 seconds to one minute. This is due to the default chunk size of 10 seconds, and typically three chunks are built before delivery is started. The total latency can stretch to over 1 minute when factoring in conversion time of the incoming video stream into HLS or DASH chunks, travel distance between source and viewer, and final delivery over the viewer’s Internet Service Provider (ISP).
The good news is there is a solution. Chunk size is the largest contributor to latency. Therefore, an obvious approach to lowering latency is to reduce it. Today, any organization that needs to deliver live video streams deploys a Content Delivery Network (CDN) to leverage its broad global coverage. This is exactly what several gaming companies are doing as part of evaluating new low-latency live streaming technologies which is now available from Limelight Networks.
There are two options in reducing latency issues in live video streaming:
- One option is to send live streams to our CDN where the conversion to HLS or DASH, 1 second chunks is performed, and the chunked streams delivered to users. By reducing the chunk size to 1 second, the previous 30-second to delivery start is cut to 3 seconds. Also, format conversion time is saved by having much smaller chunks to create. The evaluations of this method are showing live streaming latency down to about 5 seconds, a significant improvement over existing HLS and DASH live streaming delivery solutions, and is satisfactory for some gaming applications.
- Another option for small chunk size streaming is for the live stream to be converted to HLS or DASH small chunks before sending the stream to the CDN. Because the video is pre-converted to chunked streams, the CDN can zip them across the network in milliseconds, and deliver them to users, further reducing latency.
Another solution the video industry is focusing on is a technology called WebRTC (Web Real-time Communication), which is supported by all the popular web browsers. WebRTC does not use chunked streaming, does not require any browser plugin, and uses the streamlined User Datagram Protocol (UDP) or IP protocol for transport. Latencies are expected to be 1 second or less. By integrating WebRTC streaming support into a CDN, content distributors will be able to easily implement scalable live video streaming workflows.
Sports leagues and the broadcast TV networks carrying the games also embrace streaming. For example, in the English Premier League, viewership of regular season broadcasts has slipped in the recent years. Large broadcast TV networks have locked up multi-year broadcasting rights for billions of ringgit. For example, one of the leading media organizations in Malaysia have recently opted to go beyond the traditional television ecosystem by streaming their shows and sports programs online as well. With TV ratings declining, they need more viewers to bring in more ad revenue. Voila! Live streaming simulcast with the broadcast is adding millions of additional viewers.
We are on the forefront of the way low-latency live streaming will impact sports viewing and gaming. As the new technologies mature and see widespread adoption, it’s going to be a game changer. I’m certainly looking forward to how it all plays out.
*Jaheer Abbas is Regional Director SE Asia & ANZ, Limelight Networks