Hi list,
as we have encountered on the Harvard Un-Conference there are currently
some groups working on video editing functions. The bandwith of the
ideas that came up during the discussions was from compositions of video
segments that are remixed in the browser, over services that re-encode
the video based on the playlist up to streaming servers that exclude
parts of the video without the player even knowing this.
I feel the strong need that we agree on a common exchange format of the
needed video edit list. From my point of view it would be the best to
use an open standard for this and so SMIL 3.0 Tiny Profile [1] seems to
be a good choice.
As an example a "playlist" for a single stream video might look like this:
<?xml version="1.0"?>
<smil xmlns="http://www.w3.org/2001/SMIL20/Language";>
<body>
<seq>
<video src="lecturer.mpg" clipBegin="00:01:44.360"
clipEnd="00:04:06.720"/>
<video src="lecturer.mpg" clipBegin="00:38:54.480"
clipEnd="00:50:08.240"/>
<video src="lecturer.mpg" clipBegin="00:59:56.640"
clipEnd="01:13:51.720"/>
<video src="lecturer.mpg" clipBegin="00:31:28.440"
clipEnd="00:49:30.280"/>
</seq>
</body>
</smil>
If we have a dual stream video it might look like this:
<?xml version="1.0"?>
<smil xmlns="http://www.w3.org/2001/SMIL20/Language";>
<body>
<seq>
<par>
<video src="lecturer.mpg" clipBegin="00:01:44.360"
clipEnd="00:04:06.720"/>
<video src="vga.mpg" clipBegin="00:01:44.360" clipEnd="00:04:06.720"/>
</par>
<par>
<video src="lecturer.mpg" clipBegin="00:38:54.480"
clipEnd="00:50:08.240"/>
<video src="vga.mpg" clipBegin="00:38:54.480" clipEnd="00:50:08.240"/>
</par>
<par>
<video src="lecturer.mpg" clipBegin="00:59:56.640"
clipEnd="01:13:51.720"/>
<video src="vga.mpg" clipBegin="00:59:56.640" clipEnd="01:13:51.720"/>
</par>
<par>
<video src="lecturer.mpg" clipBegin="00:31:28.440"
clipEnd="00:49:30.280"/>
<video src="vga.mpg" clipBegin="00:31:28.440" clipEnd="00:49:30.280"/>
</par>
</seq>
</body>
</smil>
In general it might be useful to create a (REST)-service that delivers
the SMIL file that the current service needs. So in the player we need
one of the distribution copies (streaming or not), while we would need a
link to the source files for a re-emcoding and we might need a link to
the file in the file-system on the streaming server.
Specialized output formats like simple JSON lists that the REST-endpoint
creates might be a valid export format for the player too.
So I'm open for comments on this issue. What do others think about this
proposal? Are there alternative formats to SMIL that are worth considering?
Regards
Rüdiger
[1] http://www.w3.org/TR/smil/smil-tiny-profile.html
--
________________________________________________
Rüdiger Rolf, M.A.
Universität Osnabrück - Zentrum virtUOS
Heger-Tor-Wall 12, 49069 Osnabrück
Telefon: (0541) 969-6511 - Fax: (0541) 969-16511
E-Mail:[email protected]
Internet:www.virtuos.uni-osnabrueck.de
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