[foms] Chunked/adaptative streaming at Dailymotion

[David R]

On Thu, 4 Nov 2010 13:11:34, Pierre-Yves wrote:
> Well, not really. Akamai is sized to support such load for instance.
If you anticipate 120,000 titles, averaging 1 hour in duration, and encode at 10 bitrates (perhaps 100, 250, 350, 500, 1000, 1350, 1750, 2650, 3600, 4800), then each title consumes ~7.5GB of space.  The library will consume ~900 peta bytes of storage, across 1,200,000 video files.  If the files are physically chunked at 2 seconds, then you would have ~2,160,000,000 chunk files. 
If the system requires mutliplexed A/V streams (ala HTTP Live Streaming), and there is a need for multiple audio bitrates, and you expect a few language tracks per title, then every video stream will be replicated n times (where n is the number of audio bitrates + the # of alternate audio tracks).  We encode 3 audio bitrates, and I will assume an avg of 2 alternate audio tracks per title (each alternate track is encoded at all bitrates, but not all streams have alternate tracks).  Thus, for this exercise, n == 5.  Using physically chunked, muxed streams, the footprint is 4 exabytes across 12,000,000,000 files, 4/5 of which is consists of duplicated video bits.  Efficiently storing and caching these bits might challenge a CDN. Thus, we prefer unmuxed streams with virtual chunking (range requests).
> My guess is that you're using MPEG2-TS files ...
Our original streaming clients use ASF.  BD-Live and Apple clients use M2TS.  All others are using fragmented ISO.
FYI, our streaming traffic is ~20% of peak US internet traffic, and our content is delivered at the highest bitrate a given client's bandwidth will allow (we currently max out at 4.8mbps).  
David

 		 	   		  
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