[theora] recommendations for web video bit rates

Denver Gingerich denver at ossguy.com
Sat Mar 13 13:45:51 PST 2010

On Sat, Mar 13, 2010 at 4:11 PM, Christopher Blizzard
<blizzard at mozilla.com> wrote:
> Some people are working on a super-easy to use converter for people to
> be able to convert videos to Theora for the upcoming Get Video on
> Wikipedia push:
> http://videoonwikipedia.org/
> For the converter one thing we'd like to be able to provide is a set of
> profiles for quality, bitrates and sizes that people can use to generate
> Theora videos.  (Michael Dale wants this for Firefogg, too.)
> The number of bits that you need to allocate depends highly on the
> content - everyone here knows that - but we can come up with a rough set
> of guidelines that give a rough estimate for low/medium/high for a given
> size.  (Is it a linear scale, depending on width * height?)

It would be good to have at least one resolution/bitrate that decodes
well on mobile web browsers that support Theora (I think that's just
Firefox, but I could be wrong).  If this use case isn't specifically
targeted, it's possible that none of the selected quality levels will
play smoothly on mobile devices (or none will do so reliably).  This
would be a major impediment to Theora/Wikipedia's perceived usefulness
or competitiveness with H.264: "Why can I play YouTube on an iPhone,
but I can't play Wikipedia videos on an N900?"

Since Theora doesn't specify profiles like H.264 does, it's important
to do some testing of our own to find a particular resolution/bitrate
of Theora that most devices with a Theora-capable browser can handle.
This could be done at least with Firefox on the N900 and whichever
Firefox pre-release is available for Android (using whichever
"minimum" hardware it will support).

I'm willing to try out some videos on my N900 if someone can give me a
few to try.  I'm guessing there are others on this list that have an
N900 to try so perhaps we could split up the test cases between
multiple people.


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