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videos not running in certain PCs - no errors shown

tecnika — Thu, 15 Feb 2018 10:18:25 GMT

Hi Dave,

a student reported that her script that was working fine on both her desktop computer and her touchscreen laptop, stop working in another computer that he wanted to use for his experiments. I have tried myself and the script is running fine on my PC but on a couple of others the videos do not play.
Inquisit does not show any error and when the experiment is aborted there is no data file.
I have tried also a basic video script (that just uploads the video and the same happened).
They are short videos of 1-2 seconds and with 50 frames per seconds. The codec for mp4 is installed in all PC were the script is not working and I also tried to convert the files in wmv but the same happened. The PCs are Dell desktop computer with windows 7 64 bits if it matters. We tried also to change the monitor (they were all 60 Hz). Do you know why this happens and how to make it work?

Also he reported that in few computer the mp4 video was not a such good quality as it was in other computers. Hopefully this will be solved using wmv files instead of mp4 files, but it will be interesting to know why this is happening.

Many thanks

RE: videos not running in certain PCs - no errors shown

Dave — Thu, 15 Feb 2018 10:18:25 GMT

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[b]tecnika - Thursday, February 15, 2018[/b]

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[b]Dave - Wednesday, February 14, 2018[/b]

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[b]tecnika - Wednesday, February 14, 2018[/b]

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[b]Dave - Tuesday, February 13, 2018[/b]

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[b]tecnika - Tuesday, February 13, 2018[/b]

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No idea offhand. Some graphics card drivers have weird optional video optimization settings which can interfere with video display in some cases -- turning those off via the graphics card's settings utility may help. Beyond that, can you share one of those videos and the small test script you've been using? Just put both in a ZIP file and attach that to this thread (click +Insert -> Add File). I'll be happy to take a look at the video file and see if I can replicate the problem.

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Hi Dave,

Thanks you for your reply. Not sure which optional video optimization setting to deactivate ... luckily, after various attempts we found a software that converts files that are working on that computer.
I am wondering why certain video files run fine on windows media player or vlc but not when in Inquisit.

Thank you,

Elena

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> I am wondering why certain video files run fine on windows media player or vlc but not when in Inquisit.

Let me try to explain:
VLC comes bundled with its own set of codecs (which are used only by VLC and are not available to any other applications on the system). So, a video that works fine in VLC may very well not play in any some other application that relies on other or system-level codecs.

Inquisit 5 relies on system-level codecs, specifically Inquisit 5 relies on the Microsoft Media Foundation (MMF) framework (available and gradually extended as of Windows Vista) to render videos. The advantage of MMF is that it supports a number of common and modern video formats out of the box on current Windows versions, although it is lacking support for more exotic formats.

Inquisit 4 still relied on an older, different framework (DirectShow codecs). A vanilla Windows installation comes with relatively few DirectShow filters, and to use MP4s, for example, you'd often have to find and install a suitable 3rd party codec first.

Now, Windows Media Player can (still) use both: MMF as well as DirectShow, and which one it uses will depend on the video format, which type of codec for it is available, and settings buried pretty deeply within Windows. This explains why a certain video might play fine in Windows Media Player (per a suitable DirectShow codec), but may not work properly under Inquisit 5 (because the video isn't fully compatible with MMF).

I know this is all a bit technical, but I hope it's still somewhat useful.

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Hi Dave, thank you for your explanation. However I would expect that different computer with Windows 10 with the same updates will have the same MMF framework, won't they? The only difference I can spot is different graphic card: the one in the PC where the videos are not running is ATI. The one where the videos are running fine is Intel (R) HD Graphics. I could not find any optional video optimization settings. Not sure if there is a way to be sure that the MMF installed are the same, but I believe that's something I should figure out. Anyway as I said in the previous post the expt is running fine with the newly purchased video converted so it will not be a big deal. Hopefully, the problem could be solved using that format in future when videos will not run fine. Many thanks again!

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You are right in that two identical, vanilla Windows 10 installations (with the same Windows update status) would both have the same MMF framework available out of the box. The question is what the difference is between the two systems -- graphics card settings are one option, another application messing with the codec / MMF settings would be another. It's unfortunately hard to tell from a distance.

RE: videos not running in certain PCs - no errors shown

tecnika — Thu, 15 Feb 2018 03:44:44 GMT

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[b]Dave - Wednesday, February 14, 2018[/b]

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[b]tecnika - Wednesday, February 14, 2018[/b]

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[b]Dave - Tuesday, February 13, 2018[/b]

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[b]tecnika - Tuesday, February 13, 2018[/b]

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RE: videos not running in certain PCs - no errors shown

Dave — Wed, 14 Feb 2018 10:09:29 GMT

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[b]tecnika - Wednesday, February 14, 2018[/b]

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[b]Dave - Tuesday, February 13, 2018[/b]

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[b]tecnika - Tuesday, February 13, 2018[/b]

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tecnika — Wed, 14 Feb 2018 09:25:47 GMT

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[b]Dave - Tuesday, February 13, 2018[/b]

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[b]tecnika - Tuesday, February 13, 2018[/b]

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RE: videos not running in certain PCs - no errors shown

Dave — Tue, 13 Feb 2018 09:43:17 GMT

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[b]tecnika - Tuesday, February 13, 2018[/b]

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