[theora-dev] optimization for OLPC

Chih-Chung Chang jochang at gmail.com
Wed Feb 28 07:40:43 PST 2007


On 2/28/07, Ralph Giles <giles at xiph.org> wrote:
> On Wed, Feb 21, 2007 at 10:41:46PM +0800, Chih-Chung Chang wrote:
>
> > OLPC has a camera on it, do you think it's possible to use Theora on
> > 320x240 at 15fps for real-time encoding/decoding?
>
> In theory, but it probably needs some coding love. The libtheora encoder
> assumes it's doing batch encoding and the output delay varies wildly
> with the motion content. With a "realtime" mode it should be possible.
>
> I don't have access to the hardware. Can you try running an encode
> with libtheora 1.0alpha7 and see how far we are from realtime?

I don't have the hardware yet. I will report the number when I get it.
I found one data point in

http://mailman.laptop.org/pipermail/community-news/2006-December/000035.html

"FFmpeg's H263 codec at QCIF resolution (about 176×120) at 15 frames
per  second, taking up about 40–50% of the CPU to encode and about
10–15% to decode."


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