[theora-dev] optimization for OLPC

[Chih-Chung Chang]

Hi,

Here is the number for encoding and decoding Theora on XO-B2.
For comparison, the same test is run on Athlon-XP1800+.

Encoding:

sample         size      XO     Athlon  bitrate
-------------- --------  ------ ------- ---------
akiyo_cif      352x288   16 fps 131 fps 129 kbps
akiyo_qcif     176x144   62 fps 483 fps 40 kbps
coastguard_cif 352x288    4 fps  40 fps 863 kbps
football_sif   352x240    2 fps  24 fps 1503 kbps
foreman_cif    352x288    5 fps  44 fps 583 kbps
foreman_qcif   176x144   21 fps 182 fps 176 kbps

Decoding:
sample               size         XO      Athlon
-------------------- ---------  -------- --------
320x240              320x240     82 fps   705 fps
322x242_not-divisibl 336x256     69 fps   571 fps
Building_On_The_Past 320x240     99 fps   666 fps
Elephants_Dream_1024 1024x576     6 fps    41 fps
Elephants_Dream_512- 512x288     27 fps   169 fps
MSD_ORACLE.vlog_2    368x240    160 fps  1499 fps
chained_streams      320x240     81 fps   705 fps
monday_0930_Welcome  320x240    125 fps  1000 fps
multi2               320x240     38 fps   499 fps
pixel_aspect_ratio   352x288     32 fps   244 fps
romalcc              352x288    133 fps  1000 fps
timeskew1-t2s1       320x240     75 fps   599 fps
videotestsrc-720x576 720x576     19 fps   148 fps

The test uses dump_video and encoder_example in Theora
examples. The output is directed to /dev/null. The video
quality is set to 3 for encoding. The decoding runs for
first 120 frames only. XO's wireless is off while testing.

The encoding samples are from
http://media.xiph.org/video/derf/

The decoding samples are collected from the net:
http://www.archive.org/download/Robert_M.Albrecht_Einfuehrung_in_CreativeCommons/romalcc.OGG
http://linux.dell.com/vlogs/MSD_ORACLE.vlog_2.ogg
http://blogage.de/mirror/ogg/timeskew1-t2s1.ogg
http://people.xiph.org/~giles/2006/Elephants_Dream_512-st.ogg
http://people.xiph.org/~giles/2006/Elephants_Dream_1024.ogg
http://share.sh.cvut.cz/avc/Theora_demos/Building_On_The_Past.small.ogg
http://papaja.v2v.cc/~j/theora_testsuite/
http://mirror.linux.org.au/linux.conf.au/2007/video/monday/monday_0930_Welcome.ogg

Regards,
Chih-Chung Chang

On 2/28/07, Chih-Chung Chang <jochang at gmail.com> wrote:
> 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."
>