Originally Posted by Brian Conrad
I would urge those who want to get a handle on what your can do with Silverlight encoding (which NF uses)...
I'm pretty sure that they don't use IIS Smooth Streaming (not actually a part of Silverlight, but of a multi-media extension to IIS, MS's web server platform). Microsoft's Alex Zambelli
denies it in an an old entry in his blog. From the article
Despite popular belief, Silverlight doesn’t actually feature native support for any particular adaptive streaming technology – Microsoft’s, Netflix’s or Move Networks’ for example. Smooth Streaming support in Silverlight is implemented via the MediaStreamSource API. This API allows developers to implement their own media transport methods (instead of relying on MediaElement‘s native transport methods) while still leveraging Silverlight’s native decoders and renderers.
From the comments
August 21, 2009 at 20:26
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August 21, 2009 at 22:54
Jake, you’d probably be better off posting a comment at http://blog.netflix.com
. Netflix built their own Silverlight player, their own adaptive streaming platform, their own encoder… everything. They’re the only ones who can tell you what’s going on with their player.
I've scanned this
very dense academic technical paper comparing the performance characteristic of three adaptive bit rate streaming technologies, IIS Smooth Streaming, Netflix's system and something called OSMF. From their conclusion:
The Netflix player is similar to Smooth Streaming (they both use Silverlight for the media representation). However, we observed that the former showed some important differences in its rate-adaptation behavior, becoming more aggressive than the latter and aiming to provide the highest possible video quality, even at the expense of additional bitrate changes. Specifically, the Netflix player accumulates a very large buffer (up to few minutes), it downloads large chunks of audio in advance of the video stream, and it occasionally switches to higher bitrates than the avail-bw as long as the playback buffer is almost full. It shares, however, the previous shortcomings of Smooth Streaming.
Their Netflix web player and Window 8 app use some significant elements of Silverlight (and the web player is authored with Silverlight, MS' version of Adobe's Flash suite); I'm not sure how much. I believe that Microsoft, Netflix and several other ABS systems (including the emerging MPEG-DASH standard) are using the fragmented MP4
format, but I don't think that Netflix has used MS' Expressions encoder. They've moved away from whatever they were using to eyeIO's encoding tech in any case.
I don't know how Silverlight became synonymous with Smooth Streaming players--it's this huge suite of multi-media web authoring tools and APIs. Streaming video playback support is just a small part of it.
EDIT: After all this exposition, I re-read your post and note that you didn't say that Netflix is using MS' Smooth Streaming tech, just "Silverlight encoding", which, if taken to mean fMP4, is true. Sorry. Everybody does seem to think that Netflix is using Smooth Streaming, though.