[PD] GEM great framerate instability unless -noaudio

cyrille henry ch at chnry.net
Fri Feb 26 18:17:10 CET 2010

Matteo Sisti Sette a écrit :
> Hi,
> 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.
look like windows is still not very good with real time applications.
try upgrading to a better OS.

with linux, i don't have anything under 32, and nothing above 42.

> 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,
i do trust realtime.

> 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??
-noaudio is not the same thing than dsp off.


> thanks
> m.
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