[Theora] Playback too slow?!

Ivan Popov pin at medic.chalmers.se
Wed Mar 30 02:16:20 PST 2005

Hi Alen,

On Wed, Mar 30, 2005 at 11:45:35AM -0000, Alen Ladavac wrote:
> I am very interested in these "decode-efficient" encoding parameters. I have
> a bunch of movies in 640x480, 30fps that would need to be decodeable on a
> 733MHz Celeron. If you have some suggestions on how to encode that to double
> the decoding speed, I'd be very grateful. :)

well, unfortunately the parameter you have to tune to make the decoding
easier is the resolution. As said a 800 MHz Athlon is capable of
decoding about 528x320 (168960 pixels).
I don't think you can do 640x480 (307200 pixels, almost twice as much).
Your hardware probably would manage something like 448x336 (150528 pixels)
or a bit more if you accept framedrops at extreme motion scenes.

The fastest (known to me) theora decoder is available at konvalo.org
as "mplayer.theora-mmx".

(you install a Coda client to run Konvalo.org's environment,
then no additional installation steps are required, you can freely run
any of the about 1800 programs currently available there,
including several useful Theora-related ones, like mplayer
and theora-encoder)

> What is this theora-encoder you are using, and what those parameters mean? I
> have searched the entire svn repository for text "hqdn3d", but haven't found
> any. So I'd guess this is not the theoraenc, is it?

theora-encoder is a shell script around mplayer and theoraenc.

Due to the mplayer's awesome capability of filtering the video data
you can optimize the data for compression before it reaches theoraenc.
You can deinterlace, crop, resize and denoise, all of which helps to produce
smaller while well-looking theora files.

Your 30 fps files can be most probably detelecined to both reduce the framerate
and improve the quality.
It will help both compression and the decoding process.

For the gory details see man mplayer and the web...


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