Digital Rapids Makes Live Streaming an Olympic Event
By Carl Lindemann
The numbers are far from in, but there s no doubt that the Olympian challenge NBC Sports has taken on by bringing many events online will yield lessons that will shape future online coverage. Behind the scenes, Digital Rapids — a Canada-based developer of hardware and software for video ingest, encoding, transcoding, protection, streaming, and delivery — has created much of the infrastructure needed to make this happen.
According to Mike Nann, Digital Rapids director of marketing/communications, the key is a viewer experience closer to that enjoyed by a producer picking which feed to put front and center in the coverage.
What you watch on the TV is very constraining. It may be switching between three or four events, with 16 events happening at the same time. The difference online is that the viewer gets to decide what they will watch, including events that may not make it to the TV at all, Nann says.
He points out that getting there means beginning with a different approach. Typically, live streaming of major international events starts with the satellite transmission of a single main feed from the source location to the destination country. Then the single feed is encoded, streamed, and distributed.
With the Olympics, dozens of simultaneous live event feeds are encoded in
Beijing and streamed to the
U.S. for distribution to Web audiences. This, Nann says, puts control in the hands of the viewer, letting users watch multiple events concurrently while interactively switching among streams through a rich media experience enabled by the cross-platform Microsoft Silverlight technology.
Adding this variety seems simple, but executing it demands far more than you would guess, says Nann. On top of the obvious challenges, we ve had to work within additional constraints imposed by the
Center. We have had to operate with a limited number of rack units, limited power, and limits to the amount of heat dissipation allowed.
Staying inside these bounds called for significant innovation. How much can you squeeze out of about 50 boxes handling two streams each? With a full capacity of more than 100 live video feeds, the Digital Rapids solution is designed to encode and output three versions of each with different combinations of resolution and bit rate. This triples the amount of encoding to be performed.
Having a limited number of boxes to perform this sleight of hand is hard enough. Add the unpredictable and varying visual nature of the content – from fast-moving events with extensive camera motion to close-ups and wide shots with minimal movement – creates monstrous encoding challenges.
To tackle these issues, Digital Rapids has combined its own hardware card for pre-encoding with Dynamic Complexity, a processing strategy drawn from Microsoft s VC-1 toolkit. The pre-processing does a lot of the heavy lifting by looking at the images at the pixel level and identifying what kind of processing needs to be done where.
This takes the load off the high-end Intel Xeon Quad processors driving the full-frame compression. Dynamic Complexity watches how much processing is happening where in this second stage. This presses for optimum usage and throttles back short of choking the system.
The result speaks for itself.
NBC Universal s coverage of this year s Summer Games is raising the bar for live event streaming, says Brick Eksten, president of Digital Rapids. From the volume of live streams and the massive amount of on-demand content to the quality of the end-user experience – everything about this initiative is changing how content consumers will look at live event coverage from this point forward.
What does such innovation promise for post-Olympic sports coverage? The ability to deliver multiple streams more effectively could give fans a control-booth view of events. Applying this strategy to, say, an eight-camera football game might enable fans to enjoy the same power of presentation as the producer with access to all the video streams. Whether fans would want – or access — such opportunities isn t clear. But the desire to toggle between games and sports has never been addressed so well.