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Pavlovia: keeps loading


This error looks like a path error. You should make the path to the mp4 relative from your experiment folder. E.g., final motion clip2/video/demo/1.mp4.


@dvbridges Thank you for your help. The error box disappeared but the movie could not be played in the experiment. It instead appears with a black screen.


I have checked that all the videos could be played in the folder on Pavlovia and also the location links are correct.
Please check this link:


@dvbridges The same thing happened when I tried to upload just a movie for testing. The video could not be played and only black screen appears.


It seems to start and run ok, but when a movie plays you get a black screen. Looking at your movie stim code, it looks like your movie sizes have gone wrong. PsychoPy will default to height screen units if you have not set you experiment settings to something other than “use prefs”, so currently your video is playing in height units, (where 1 is the height of your screen) but your video is sized [1440, 758], so that means the video is sized 758 screen heights on the y-axis - this is why you cannot see it. If you want to use pixels, set your experiment settings screen units to pixels.


@dvbridges thank you for your answer. I deleted all the numbers in the movie sizes. The first few videos works, however, when I deleted the movie size inside the loop, the whole experiment return to the first stage, which is a “white slide with loading” and cannot proceed to the experiment.


@dvbridges besides there is a loading problem, if the rating scale was not able to be shown.

This is the online version:

This is what it suppose to be like:


@Winnyue, apologies I did not mean for you to delete the sizes - see the documentation for information about sizing your stim.


@Winnyue, you need to use Sliders for online, not rating scale. Slider replaces the rating scale, and so rating scale object does not work for online studies.


@dvbridges i see, sorry for misunderstanding, but i have tried changing the size to (1,0.56) as the original size of the video is 1280 x 720, the video cannot be shown either. A blank frame appears in the loop instead.


@dvbridges Thanks for the suggestion. I will change it to a Slider instead of using the rating scale. But currently, i encountered one problem. As I would like to show the marks of the slider while the participant is sliding the bar, I tried to add a code on the slider:

sliderposition = []
sliderposition = slider_2.getMouseResponses()

text_82 = visual.TextStim(win=win, name='text_82',
    text= '%3i' %(sliderposition),
    pos=(0, 0.3), height=0.03, wrapWidth=None, ori=0, 
    color='white', colorSpace='rgb', opacity=1, 

However, this error popped up:

I have tried using '%s' %(sliderposition) instead of '%3i' %(sliderposition). They both did not work


You should not need a code component for this. Have a look at this example, the text component is updated every frame with the sliders marker position.

:updateText.psyexp (6.1 KB)

If you did want to use a code component, then in the “Every Frame” tab you would use:

# or 
text_82.text = slider.markerPos

@dvbridges I see!!! Thank you so much!!! Would you suggest a method to deal with the movie size problem? as i have tried changing the size to (1,0.56) as the original size of the video is 1280 x 720, the video cannot be shown either. A blank frame appears in the loop instead.


Your other videos seem to play ok at the beginning, so just do whatever you are doing there, if they are sized as you want them


@dvbridges Yes, i deleted the numbers in the size column and leave it blank. However, there is a problem when it comes to the loop.


What is the problem with the loop?


@dvbridges I have no idea cause the problem only appears on the loop so I suppose there’s some problem with the loop…


A description of the problem would be helpful for debugging. First though, I would change the rating scale to a Slider and get that working.


@dvbridges Thank you for the suggestion. I have changed the rating scale to a slider and tried to create box with text which participant could press the number shown to proceed to next question. However, the coding seems does not work on Pavlovia, including the part I use the code to calculate the total marks (I did it by adding the code to the text). Also, the movie problem still exist, movie remains a blank black frame in the loop, and for movies that are not included in the loop, the movie freeze sometimes.

Please refer to this link:


Hi @Winnyue, there appears to be an issue with the size of movie_7. It looks like a space has been added to the size parameter. If there is a space, delete the space and try again . Otherwise, please let me know, and then add an actual size e.g., [.6, .4].