Millisecond Forums » Millisecond Forums » Inquisit 6 » Videos delayed and slowed-down in the Inquisit Web Player

Videos delayed and slowed-down in the Inquisit Web Player

EvLan — Mon, 24 Oct 2022 11:45:17 GMT

Hello :)
I am currently trying to run an experiment on Inquisit Web, in which short video and audio clips are presented simultaneously to the participants. I tested the study on several Laptops and PCs (Windows and Apple) and didn’t run into any issues regarding the presentation of the stimuli.

I therefore started collecting data from real participants and soon got feedback that for some of them the videos didn’t play correctly, but either started much later than the audio or played “in slow motion”… The only information about the technical equipment of these participants I have is that they used Windows as operating system (Windows 8, Windows 10).

Since I have not been able to reproduce the problem with the computers I have access to, I’m afraid this might be a tricky one to solve. Nevertheless, I wanted to ask whether you have any ideas what causes these issues.
Thanks a lot in advance!

RE: Videos delayed and slowed-down in the Inquisit Web Player

EvLan — Mon, 24 Oct 2022 11:45:17 GMT

+x[quote]

[b]Dave - 10/24/2022[/b]
+x[quote]

[b]EvLan - 10/24/2022[/b]
Hello :)
I am currently trying to run an experiment on Inquisit Web, in which short video and audio clips are presented simultaneously to the participants. I tested the study on several Laptops and PCs (Windows and Apple) and didn’t run into any issues regarding the presentation of the stimuli.

I therefore started collecting data from real participants and soon got feedback that for some of them the videos didn’t play correctly, but either started much later than the audio or played “in slow motion”… The only information about the technical equipment of these participants I have is that they used Windows as operating system (Windows 8, Windows 10).

Since I have not been able to reproduce the problem with the computers I have access to, I’m afraid this might be a tricky one to solve. Nevertheless, I wanted to ask whether you have any ideas what causes these issues.
Thanks a lot in advance!
[/quote]

Windows 8 is not supported, the official requirement for Inquisit 6 is at least Windows 10 ( cf. https://www.millisecond.com/products/requirements ).

If videos have playback issues, that typically points to either a codec problem and/or the device not having a sufficiently powerful graphics card to render the videos at full speed. You didn't say anything about your videos' encoding, so here are a few general recommendations:
(1) Use MP4 containers.
(2) Encode the video stream with H.264.
(3) Use MP3 for the audio stream.
(4) Don't go overboard on video resolution, go for 480p or even 240p if possible; 720p or above may be too much to handle for systems with weak graphics cards.
[/quote]

Thank you so much for the quick reply!

It's my first time using videos in a study so these information are extremely helpful.
I will adjust my videos according to your recommendations.

Thank you very much! :)

RE: Videos delayed and slowed-down in the Inquisit Web Player

Dave — Mon, 24 Oct 2022 11:30:10 GMT

+x[quote]

[b]EvLan - 10/24/2022[/b]
Hello :)
I am currently trying to run an experiment on Inquisit Web, in which short video and audio clips are presented simultaneously to the participants. I tested the study on several Laptops and PCs (Windows and Apple) and didn’t run into any issues regarding the presentation of the stimuli.

I therefore started collecting data from real participants and soon got feedback that for some of them the videos didn’t play correctly, but either started much later than the audio or played “in slow motion”… The only information about the technical equipment of these participants I have is that they used Windows as operating system (Windows 8, Windows 10).

Since I have not been able to reproduce the problem with the computers I have access to, I’m afraid this might be a tricky one to solve. Nevertheless, I wanted to ask whether you have any ideas what causes these issues.
Thanks a lot in advance!
[/quote]

Windows 8 is not supported, the official requirement for Inquisit 6 is at least Windows 10 ( cf. https://www.millisecond.com/products/requirements ).

If videos have playback issues, that typically points to either a codec problem and/or the device not having a sufficiently powerful graphics card to render the videos at full speed. You didn't say anything about your videos' encoding, so here are a few general recommendations:
(1) Use MP4 containers.
(2) Encode the video stream with H.264.
(3) Use MP3 for the audio stream.
(4) Don't go overboard on video resolution, go for 480p or even 240p if possible; 720p or above may be too much to handle for systems with weak graphics cards.