Trouble with sound in an experiment with video clips.

Maria1

Hello,

I am having trouble with presenting a video clips in my experiment. The problem is that sound disappears shortly after playback starts. There is no pattern to it: sometimes it plays a few seconds, other times it last for the half of the video before getting muted. It is very a simple experiment, where participants get 7 randomly presented video clips (3 minutes long at average), and answer a 1 item questionnaire on a 5 point scale followed by 2 minutes pause. I have read many discussions on the platform and tried to change and combine some settings, but nothing worked so far.

Here are the things I've tried:

• updated the software
• installed the movie plugin
• changed backends (video plays only in PyGame, all other backends play the sound but not the visuals, the screen stays black)
• adjusted settings for legacy (like reducing sampling frequency or increasing sound buffer size)
• converted the videos in .flv and .avi, tried it as mp4, the problem remains
• tried to play it in all three sound renderer settings (sounddevice, pyaudio, pygame only the last one allows the experiment to run, the other two result in experiment failure)
• disabled the scaling of video size to the screen, so they play as originals (to save cpu capacities) These seven videos all have different resolutions, smaller or bigger: it does not influence the occurring problem

Now I have reached the point where I have no Ideas left. So if anybody would be so kind as to think with me, trying to solve this problem, I would be endlessly thankful.

Best Regards,

Maria

robbertmijn

Hi Maria,

Sound like you've already tried quite a bit. What platform do you use opensesame on? (windows, mac, or linux?)

Kindly, Robbert

Maria1

Hi Robert,

i've run it on both mac and windows platforms, the problem persists regardless of the operational system.

robbertmijn

Hi, sorry for taking so long to get back!

It sounds like you've tried most of the things I would recommend. Maybe the problem lies with the media you're trying to play. Can share one of the videos that gives a problem?

robbertmijn

In any case, currently on mac the video playback is only supported using either pygame or expyriment with the pygame sound renderer. It sounds like you tried those 2 combinations (can you confirm this?).