Audiovisual Asynchrony on Pavlovia

Online experiments
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1

Hello,

I am trying to run an audiovisual experiment on Pavlovia. However, I noticed that there is an audiovisual asynchrony.

So basically on each trial, there is a speaker uttering a sentence (the files are about 3-4 seconds long) and participants are asked to press a key.

How can I fix this asynchrony issue?

Also, I was wondering if someone can help me understand the difference between moviepy, avbin, and opencv.

Any help would be appreciated. Thanks

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By first describing it.

None of them are used for online experiments – they are options only relevant to Python scripts run locally.

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The experiment has a training and a test phase.

During the training phase, we are presenting movie files (3-4 seconds each) of speakers uttering a sentence. After the trial ends, participants are asked to press a key on their keyboard. We have a total of 200 trials of video/audio presentations and none of the files are repeated.

We are experiencing an audiovisual asynchrony (the audio is leading video) during training.

During the test phase, we are presenting audio files (again 3-4 seconds each) of speakers uttering a sentence and after which participants are asked to press a key on their keyboard. Again we have a total of 200 trials and none of the files are repeated.

So the experiment has a lot o resources to download (about 450). Could this cause the audiovisual asynchrony?

I am also including the link to my experiment here: Serena Zadoorian / AV Training_Bimodal Rep. · GitLab

5

Hi @serena_zadoorian, thanks for flagging. I have no concrete solution for you yet, but can confirm the asynchrony and that the issue is unrelated to the number of videos being loaded. I appreciate your patience while I look for a fix, s.

6

Hello,

Thank you so much for developing a new version of PsychoPy. The new release is definitely helpful. I was also wondering if you have looked more into the audiovisual asynchrony issue on Pavlovia?

Thanks in advance for your time!

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Dear @serena_zadoorian, sorry I got delayed working on the new release and should be able to spend more time on this in the coming days. Many thanks again for your patience while I look for a solution, x

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Hello @sotiri,

I would like to follow up on my previous post. Were you by any chance able to look more into the audiovisual synchrony issue?

Thanks in advance

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Hi @serena_zadoorian, apologies again for the late response. I am hoping we can at some point implement the necessary rendering improvements in PsychoJS. For the time being, I believe your best bet would be to rely on the HTML video element backing up MovieStim and have updated the support fork to demonstrate how to overlay that on top of canvas. Please let me know if that covers your needs, x