[Theora] Playback too slow?!

Alen Ladavac alenl-ml at croteam.com
Wed Mar 30 04:56:00 PST 2005

Ah, I see, so those options are for downsampling and denoising. Well, the
movies are rendered CG animations, so there is no transmission noise in
them. I guess denoising probably would not help, right? (Btw, I was wrong,
the movies are 640x360 in fact, because they are cut to wide screen format,
so that helps a bit.)

I've seen the Coda website and it is cool, but it doesn't help really,
because the playback will be done on a closed platform (Xbox), so we have to
use libtheora directly from our code. Btw, which codebase is that mmx
decoder of yours based on? Is that the mmx branch in the Xiph SVN
repository, or something else?

I just thought you were using some magic options I don't know about. So,
guess we are back to those peephole optimizations on the mmx decoder. We are
looking for the best mmx implementation to base our optimizations on, and we
are probably going to multithread it and pre-buffer about a dozen frames or
so, to smooth out the peaks. Any additional ideas are welcome. This just
_has_ to work 30fps straight, no drops.


----- Original Message -----
From: "Ivan Popov" <pin at medic.chalmers.se>
To: "Alen Ladavac" <alenl-ml at croteam.com>
Cc: "Ole Tange" <tange at tange.dk>; <theora at xiph.org>
Sent: Wednesday, March 30, 2005 10:16
Subject: Re: [Theora] Playback too slow?!

> 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
> > a bunch of movies in 640x480, 30fps that would need to be decodeable on
> > 733MHz Celeron. If you have some suggestions on how to encode that to
> > 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
> > 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
> smaller while well-looking theora files.
> Your 30 fps files can be most probably detelecined to both reduce the
> and improve the quality.
> It will help both compression and the decoding process.
> For the gory details see man mplayer and the web...
> Regards,
> --
> Ivan

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