Memory Error with MovieStim3

[Mohit Goel]

Dear Psychopy users,

I am performing an experiment where I have to show movie clips to the participants. In total movie clips are 10-15 min long. When I try to run the program then after about 7-8 min it gives me the error :

"Fatal Python error: (pygame parachute) Segmentation Fault"

and the program stops. Mostly, from the previous discussions on this forum, I came to an understanding that I might be due to memory card buffer. That is, the buffer is not able to capture this much long movie at a time. Can anyone tell me how to solve this?

Is there a way that I keep clearing my buffer after every short clip?

Thanks,

Mohit

[Frank Papenmeier]

Dear Mohit,

are you using Mac OS X? We are also experiencing segmentation fault errors in an experiment using MovieStim3 from time to time. However, we had not yet considered that MovieStim3 might be the reason because it works just fine on two Mac Minis and gives regular segmentation fault errors on a third Mac Mini. However, in our experiment the segmentation fault does not occur reliably but only from time to time. It might therefore also be a completely different issue in our experiment. Is it the same with your experiment or do you receive this error during each and every run of the experiment?

All the best,

Frank.

[Richard Höchenberger]

On Wed, May 11, 2016 at 1:42 PM, Mohit Goel <mgoe...@gmail.com> wrote:
> "Fatal Python error: (pygame parachute) Segmentation Fault"

Could you try passing the noAudio=True argument when instantiating
MovieStim3? That is, mov = visual.MovieStim3(..., noAudio=True)?

[Mohit Goel]

Dear Frank,

I am using Windows-8 for performing this experiment. In your experiment are you using the same stimuli in all 3 Mac Minis?

I am getting this error every time the total duration of my movie clips( multiple clips each of 2-3 min duration ) exceeds 8-9 min. So as long as total duration of my movie clips remain below this value everything works fine else it gives me this error.

Thanks,

Mohit

[Richard Höchenberger]

On Thu, May 12, 2016 at 8:04 PM, Mohit Goel <mgoe...@gmail.com> wrote:

I am getting this error every time the total duration of my movie clips( multiple clips each of 2-3 min duration ) exceeds 8-9 min. So as long as total duration of my movie clips remain below this value everything works fine else it gives me this error.

Oh, wow, this is interesting! So this happens even if you split the movies into small parts? As long as the total duration within one script exceeds ~9 min, it crashes??

    Richard

[Mohit Goel]

Dear Richard,

I tried it and it started working fine. So my movie clips are working but sadly audio is also important for my experiment. So please can you think of some other fix as well.

Thanks,

Mohit

[Richard Höchenberger]

On Thu, May 12, 2016 at 10:39 PM, Mohit Goel <mgoe...@gmail.com> wrote:

I tried it and it started working fine. So my movie clips are working but sadly audio is also important for my experiment. So please can you think of some other fix as well.

So I guess it's a bug that needs fixing somewhere upstream, either in PyGame or in moviepy.

Could you try converting the audio streams of the movie files to another format, say, WAV?

    Richard

[Frank Papenmeier]

Am Donnerstag, 12. Mai 2016 20:04:51 UTC+2 schrieb Mohit Goel:

I am using Windows-8 for performing this experiment. In your experiment are you using the same stimuli in all 3 Mac Minis?

Dear Mohit,

yes, we are using the same stimuli on all our 3 Mac Minis. Also given that your experiment crashes each and every time, this is likely a different issue you are experiencing here. I hope that the suggestion of Richard to convert your audio stream to WAV will solve your issue.

All the best,

Frank.

[Jonathan Peirce]

OK, well this was a good test my guess is that the audio *output* is the problem (e.g. a bug in pyo) rather than the reading in of the audio. MovieStim3 uses whatever your audio preference is set to (PsychoPy preferences dialog) so maybe you could try one of the other options. Try setting it to each of these in turn ['pyo'], ['pygame'], ['pysoundcard'] and see if any of the three works (or, if the problem changes then give us the new error message)

thanks
Jon

-- 
Jonathan Peirce
University of Nottingham

http://www.peirce.org.uk

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[Jeremy Gray]

One possible issue: There used to be a bug in pyo that lead to a memory error. The bug was fixed, but you might not have the latest version of pyo, and so are still encountering the bug.

--Jeremy

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