[theora] Http adaptive streaming for html5

Conrad Parker conrad at metadecks.org
Sun Dec 20 19:23:12 PST 2009

2009/12/21 Michael Dale <mdale at wikimedia.org>:
> Chris Double wrote:
>> I'm not sold on the approach of listing the different bitrate versions
>> in source elements. This will cause issues if the source elements have
>> different codecs, sizes, or other characteristics. It also makes it
>> hard to know which is a 'fallback' source and which is a bitrate source.
>> I much prefer the approach of treating bitrate switching as a new
>> codec. Have a file on the server that lists the different bitrate
>> versions. Much like Apple's live streaming draft RFC.
>> In this way browsers can support it by implementing the 'codec' and
>> the WHATWG doesn't need to be involved at all as far as I can tell.
>> Chris.
> Hmm...if externally describing the resource set.  There is the
> xiph/annodex "roe" xml format: http://wiki.xiph.org/ROE  which is
> probably slightly less arcane than writing a bunch of
> lines and potentially having to segment all media files.

Right, so I think the main thing to spec out first is the use cases. I
guess from Michael's point of view, the content site is both in charge
of the videos and the html, so it's ok for the web page to list all
the optional sources.

However if the web page and the content are from different places (eg.
a random blog article embedding a youtube/tinyvid/whatever video) then
the blog author can't be expected to know all the options or be
authoritative for them, and it makes more sense to simply link to a
single media type which then describes the options.

I think it's useful for people to be able to take video that is
published under the first scenario and link to it externally -- to
simply be able to take the contents of <video src="..."/> and copy
that into their blog. I think listing all the options in the markup
would make that difficult; I think the list of options should be under
the control of the video host, and they should be able to change them
over time (eg. offering more versions for more popular videos).


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