The Olympics are upon us – again! Even though the ancient Greeks set the Olympic schedule 4 years apart (in fact, the literal definition of an Olympiad is “4 years”), the modern Olympics since 1992 have been only 2 years apart due to the interleaving of the Summer and Winter games. In 2008 I got involved in my first Olympics streaming project (while at Microsoft, for NBC), and here we are 6 years later and I am now involved in my 4th consecutive Olympics project, this time with iStreamPlanet and again for NBC. Incidentally, it is also iStreamPlanet’s 4th consecutive Olympics, but this time it’s a particularly special occasion. This time we’re encoding it with our own software.
What makes the Olympics stand out in the world of live video streaming is their formidable combination of volume and (in)frequency. Whereas most live sporting events take place on a weekly or monthly basis and wield modest viewership numbers, the Olympic Games are recurring 2-year events that can feature up to 30-40 concurrent live streams and attract millions of viewers over the course of 2 weeks. That means that anybody wishing to prepare for such an event must plan for 2 weeks of high volume operations (including capex and staffing), but then also be ready to give it all up after the 2 weeks of excitement are over. Such need for extreme elasticity and scalability makes these Olympic projects perfect candidates for cloud computing - and cloud encoding in particular.
Another fascinating aspect of Olympics streaming is that it happens just sporadically enough to truly show how far streaming technology has advanced since the previous Olympics. Every Olympics streaming project pushes the envelope of streaming media technology, making each and every Olympics feel like a brand new baptism of fire. When I was involved in the 2008 Beijing Olympics, the live video streaming technology was still Windows Media based and streaming to mobile devices seemed like an extravagant idea. The live video was compressed with VC-1 codec and it peaked at 592×336 resolution (600 kbps), which at the time (before live adaptive streaming) was deemed about as high as we could realistically go without risking last-mile delivery issues. We couldn’t even dream of SD 480p streaming, let alone HD 720p streaming.
Fast forward 2 years to Vancouver 2010 Olympic Games – and the streaming technology had already advanced by leaps and bounds. By February 2010 Microsoft had officially launched Smooth Streaming, its HTTP-based adaptive streaming technology, and 720p HD streaming video was now officially a reality. iStreamPlanet did the live encoding for those Olympics, using Inlet/Cisco encoders and VC-1 codec, and it was quite possibly the best live video streaming the world had seen at that point. Microsoft’s subsequent 2012 London Olympic efforts iterated on those Vancouver foundations by replacing VC-1 with H.264 and for the first time introducing Windows Azure’s cloud computing potential on the origin/services side. Which brings us to 2014 Sochi.
iStreamPlanet’s involvement in these 2014 Olympics consists of:
- acquiring IP-based video feeds from NBC/OBS
- scheduling Aventus channels in our internal CMS
- encoding live multi-bitrate video in Aventus for delivery to Windows Azure Media Services
- inserting ad markers into live streams to enable downstream ad insertion scenarios
The live Olympic video feeds are delivered to us over a private fiber IP connection as 20-25 Mbps 1080i H.264-compressed MPEG-2 Transport Streams. Aventus, our cloud-based video encoding software, then ingests those MPEG transport streams and transcodes them to 7 different video bitrates before publishing them to Windows Azure Media Services entry points.
Aventus “talks” to WAMS live publishing points using Smooth Streaming as its transfer protocol, but WAMS then uses its Dynamic Packaging feature (popularly known as Dynamux) to re-multiplex the Smooth streams to Apple HLS and Adobe HDS formats for delivery to end users. The live content is pulled from WAMS origins by Akamai CDN and distributed throughout their network to viewers playing back NBC Olympics content on Windows, MacOS, iOS, Android and Windows Phone devices.
The Smooth/HLS/HDS live streams are compressed using H.264 and AAC codecs for video and audio, respectively. Audio is encoded as 56 kbps stereo HE-AAC v1, whereas video is delivered as H.264 in multiple bitrates/resolutions:
|Bit Rate (kbps)||Resolution|
This somewhat odd encoding profile (where particular resolutions are duplicated) was specifically created in order to minimize the number of client-side resolution changes, but otherwise follows fairly standard bitrate progressions.
Another interesting aspect of the Aventus Olympic workflow is ad insertion. Aventus receives REST-based API calls for ad insertion from ad operators via its Video CMS, which it converts to XML-formatted SCTE-35 cue messages and inserts into Smooth Streaming sparse tracks. Those ad markers are then converted to HLS and HDS ad markers by WAMS which downstream video players can interpret and take appropriate actions.
The most groundbreaking thing about these Olympics is that they are the first Olympics to be streamed (acquired, encoded, packaged, delivered) entirely in the cloud. If you’re in the U.S., I hope you’re enjoying watching the Sochi Olympics online. If not… well, there’s always Rio 2016.