Millisecond Forums

video not playing on some computers

https://forums.millisecond.com/Topic31349.aspx

By nrouhani - 4/14/2021

hello, 

i would like to play a video (mp4) in my experiment (code below), and it has been running on my computer (and others), but on some it just shows a blank screen (for example on MacOS Big Sur version 11.1). Is there anything I could do to prevent this from happening? (I tried to upload a zipped folder with the video but I think it's too large to upload to this post). 

thank you for your help!!
nina

*************************************************
DEFAULTS
*************************************************

<defaults>
/ minimumversion = "6.1.0.0"
/ fontstyle = ("Arial", 3%, false, false, false, false, 5, 1)
/ txcolor = white
/ txbgcolor = black
/ screencolor = black
/ canvasaspectratio = (4,3)
</defaults>

<shape blank>
/ color = black
/ shape = rectangle
/ size = (100%, 100%)
</shape>

*************************************************
EXPERIMENT
*************************************************

<expt>
/ blocks = [1=wof_spin]
</expt>

*************************************************
INSTRUCTIONS
*************************************************

<htmlpage instructions_wof_win>
/file = "intro_wof_win.htm"
</htmlpage>

<htmlpage instructions_wof_spin>
/file = "intro_wof_spin.htm"
</htmlpage>

<htmlpage instructions_wof_win_out>
/file = "intro_wof_win_out.htm"
</htmlpage>

*************************************************
BLOCK WHEEL OF FORTUNE
*************************************************

<block wof_spin>
/ preinstructions = (instructions_wof_win,instructions_wof_spin)
/ trials = [1 = wheel]
/ postinstructions = (instructions_wof_win_out)
</block>

<trial wheel>
/ stimulustimes = [0=wof]
/ timeout = 22000
</trial>

*************************************************
Stimuli Presentation
*************************************************

// lottery
<video wof>
/ items = ("wof_win.mp4")
/ playthrough = true
/ position = (50, 50)
</video>
By Dave - 4/15/2021

 
nrouhani - 4/15/2021
hello, 

i would like to play a video (mp4) in my experiment (code below), and it has been running on my computer (and others), but on some it just shows a blank screen (for example on MacOS Big Sur version 11.1). Is there anything I could do to prevent this from happening? (I tried to upload a zipped folder with the video but I think it's too large to upload to this post). 

thank you for your help!!
nina

*************************************************
DEFAULTS
*************************************************

<defaults>
/ minimumversion = "6.1.0.0"
/ fontstyle = ("Arial", 3%, false, false, false, false, 5, 1)
/ txcolor = white
/ txbgcolor = black
/ screencolor = black
/ canvasaspectratio = (4,3)
</defaults>

<shape blank>
/ color = black
/ shape = rectangle
/ size = (100%, 100%)
</shape>

*************************************************
EXPERIMENT
*************************************************

<expt>
/ blocks = [1=wof_spin]
</expt>

*************************************************
INSTRUCTIONS
*************************************************

<htmlpage instructions_wof_win>
/file = "intro_wof_win.htm"
</htmlpage>

<htmlpage instructions_wof_spin>
/file = "intro_wof_spin.htm"
</htmlpage>

<htmlpage instructions_wof_win_out>
/file = "intro_wof_win_out.htm"
</htmlpage>

*************************************************
BLOCK WHEEL OF FORTUNE
*************************************************

<block wof_spin>
/ preinstructions = (instructions_wof_win,instructions_wof_spin)
/ trials = [1 = wheel]
/ postinstructions = (instructions_wof_win_out)
</block>

<trial wheel>
/ stimulustimes = [0=wof]
/ timeout = 22000
</trial>

*************************************************
Stimuli Presentation
*************************************************

// lottery
<video wof>
/ items = ("wof_win.mp4")
/ playthrough = true
/ position = (50, 50)
</video>

(1) Specify a /size in the <video> element.

(2) Try re-encoding the video with a different codec. MP4 is a container format, it says nothing about the codecs and settings used to encode the video and audio streams in the MP4 container. Inquisit relies on the codecs available on the given system, if no suitable codec is available on the system, the video will either not render at all or it will not render properly. Typically, H.264 for the video stream and MP3 for the audio stream will work reasonably well across systems.