Millisecond Forums

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alisonmarie526 - 8/23/2021

Hi all! I'm running into an error in which Inquisit Web Player is playing the audio but not the video for an online experiment for a subset of participants. The participant reported that she could hear the music that accompanies the video clip but none of the images. She has tried re-downloading Inquisit Web Player and has ensured that Inquisit has the correct accessibility settings. She is able to see other blocks of the experiment, including surveys and separate experiment blocks. The machine she is using is a new MacBook Pro with the latest software (happy to provide additional details about the hardware of the computer if needed). Below is the Inquisit script for the block that is not playing correctly. Please let me know if you have thoughts about why this is occurring or if additional details would be helpful to debug this issue. 


<video positive_affect_manip>
/ items = ("positive_task1_standard.mp4")
/ playthrough = true
/ position = (50%, 50%)
/size = (50%, 50%)

</video>

<trial positive_affect_manip_trial>
/ stimulustimes = [0=video.positive_affect_manip]
/ validresponse = (" ")
/ timeout = 5000
</trial>

<block pos_affect_manip>
/trials=[1=positive_affect_manip_trial]
</block>

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Dave - 8/23/2021

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alisonmarie526 - 8/23/2021

Hi all! I'm running into an error in which Inquisit Web Player is playing the audio but not the video for an online experiment for a subset of participants. The participant reported that she could hear the music that accompanies the video clip but none of the images. She has tried re-downloading Inquisit Web Player and has ensured that Inquisit has the correct accessibility settings. She is able to see other blocks of the experiment, including surveys and separate experiment blocks. The machine she is using is a new MacBook Pro with the latest software (happy to provide additional details about the hardware of the computer if needed). Below is the Inquisit script for the block that is not playing correctly. Please let me know if you have thoughts about why this is occurring or if additional details would be helpful to debug this issue. 


<video positive_affect_manip>
/ items = ("positive_task1_standard.mp4")
/ playthrough = true
/ position = (50%, 50%)
/size = (50%, 50%)

</video>

<trial positive_affect_manip_trial>
/ stimulustimes = [0=video.positive_affect_manip]
/ validresponse = (" ")
/ timeout = 5000
</trial>

<block pos_affect_manip>
/trials=[1=positive_affect_manip_trial]
</block>

For displaying videos, Inquisit relies on the underlying operating system, i.e. it does not bring its own codecs (which would be prohibitive in terms of download size and the like).

If the file's video stream does not render properly on the given system, it means the system either doesn't have a suitable video codec available or some other setting on the system is off (some graphics card drivers' hardware accelaration settings can cause problems, for example).

There's not much you can do about that, except for re-encoding the video with a different codec / different codec settings. (MP4 is merely acontainer format, which in and of itself doesn't say anything about how the video stream inside the container is encoded.)

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alisonmarie526 - 8/24/2021

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Dave - 8/23/2021

+x

 

alisonmarie526 - 8/23/2021

Hi all! I'm running into an error in which Inquisit Web Player is playing the audio but not the video for an online experiment for a subset of participants. The participant reported that she could hear the music that accompanies the video clip but none of the images. She has tried re-downloading Inquisit Web Player and has ensured that Inquisit has the correct accessibility settings. She is able to see other blocks of the experiment, including surveys and separate experiment blocks. The machine she is using is a new MacBook Pro with the latest software (happy to provide additional details about the hardware of the computer if needed). Below is the Inquisit script for the block that is not playing correctly. Please let me know if you have thoughts about why this is occurring or if additional details would be helpful to debug this issue. 


<video positive_affect_manip>
/ items = ("positive_task1_standard.mp4")
/ playthrough = true
/ position = (50%, 50%)
/size = (50%, 50%)

</video>

<trial positive_affect_manip_trial>
/ stimulustimes = [0=video.positive_affect_manip]
/ validresponse = (" ")
/ timeout = 5000
</trial>

<block pos_affect_manip>
/trials=[1=positive_affect_manip_trial]
</block>

For displaying videos, Inquisit relies on the underlying operating system, i.e. it does not bring its own codecs (which would be prohibitive in terms of download size and the like).

If the file's video stream does not render properly on the given system, it means the system either doesn't have a suitable video codec available or some other setting on the system is off (some graphics card drivers' hardware accelaration settings can cause problems, for example).

There's not much you can do about that, except for re-encoding the video with a different codec / different codec settings. (MP4 is merely acontainer format, which in and of itself doesn't say anything about how the video stream inside the container is encoded.)

This is really helpful! I did contact the participant and when I sent the mp4 directly, the video did render correctly on their system. Is it possible that this issue has to do with this experiment being run online and using Inquisit Player?

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alisonmarie526 - 8/24/2021

The participant indicated that they were able to play the video using Quicktime (the default video player) on their Mac.

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Dave - 8/27/2021

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alisonmarie526 - 8/24/2021

The participant indicated that they were able to play the video using Quicktime (the default video player) on their Mac.

Just wanted to let you know that we've had no luck reproducing this on any of our Macs. Not sure what the missing factor re. the participant's Mac may be.