[PD] Gem -0.87 Performance Tuning (disk IO)

guenter geiger geiger at xdv.org
Sat Dec 7 17:08:09 CET 2002

Hi Ben,

you might try to convert the image into a movie.
This could be done on Linux with ffmpeg for example.

On the Gem side image loading could be put into a additional
thread to prevent such problems.


Music Technology Group - UPF, Barcelona <http://www.iua.upf.es/mtg/eng/>
AGNULA - A GNU Linux Audio distribution <www.agnula.org>
DeMuDi - Debian Multimedia Distribution <www.demudi.org>

On Sat, 7 Dec 2002 bbogart at ryerson.ca wrote:

> Hello All,
> I'm working on the implimentation of my thesis
> project in pd/Gem and have run into some performance
> issues (in linux using -rt).
> I have 4 video clips (Photo JPEG 256x256 quicktimes
> from 3000-11000 frames) and about 800 128x512 jpeg
> stills.
> any two of the 4 video clips are playing at any one
> time, and being mixed using alpha.
> Three of the jpegs are being used at any one time.
> The jpegs are chosen by the output of some chaos math.
> The video stuff playes great on its own, and the
> stills come up great too, animation is smooth and
> nice (Geforce2 MX-400)
> The problem is that when I load a new set of jpegs
> the video playback freezes for about 500ms and then
> continues. It looks like its the disk access causing
> the issue, since the videos are being played off
> disk. I tried putting the videos on a different HD
> than the images, but there is still that pause.
> Anyone have any suggestions on what I could do to
> improve the performance? This is an installation and
> as such needs to run for days on end without a
> performance drop.
> In my tests using the images without the video I
> could open a new jpeg every 80ms or so, very
> impressive. But why the video render pause? I
> thought about using pix_multiimage, but 800 128x512
> tiffs is probably too much for my 640MB of RAM.
> Any suggestions would be appreciated.
> Thanks
> Ben
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