[PD] GEM great framerate instability unless -noaudio

Matteo Sisti Sette matteosistisette at gmail.com
Fri Feb 26 16:50:57 CET 2010


On my Vista machine, I get an enormous instability of the framerate with 
Gem, even if dsp is switched off. However, if I run PD with the 
"-noaudio" flag, then the framerate is perfectly stable.

Is it normal?

When I say "enormous" I mean the time elapsed between a frame and the 
next one often goes below one millisecond and above 80ms, though an 
avarage of 40ms is always maintained.

I am testing this with the attached patch, which has only a gemhead and 
a [realtime], so there's no actual processing of image or video.

If anyone doubts that it can be just the time shown by [realtime] that 
is unreliable, note that if I run Pd with -noaudio the measured 
framerate actually _is_ much more stable (rarely below 37ms or above 
43ms a frame) and also, I have tried it with a simple video (homer.avi) 
and I could note the jerky playing.

Isn't it strange that turning off DSP does not change anything while 
running Pd with -noaudio does??


Matteo Sisti Sette
matteosistisette at gmail.com
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