JSPsych video to image transition flicker/lag

[cratlagh]

NOTE: This issue seems to be exclusively related to videos and their loading time, even when using preload.

Description of the problem: In a given trial I am presenting, sequentially, videos and images (in the order of video, image, video, video, image, video, image) and the net effect is a seamless animation, or at least that's what is intended. The issue arises when transitioning from an image to an video; there is at least one blank background frame (sometimes more) visible between presentations with the effect being a flicker/lag between stimuli.

Without going into too much detail, we're using videos and images for multiple response collections (which is the main reason), and also for ease of duration manipulation of single frame sections rather than building new videos every time we want to make a small change.

Any idea of how to get around this?

I am already preloading the stimuli files, and have tried using html-keyboard-response for images and videos which present successfully but the flicker/lag persists.

Worst case scenario I'll make a single video for each condition and collect the requisite attention check response, and add the task response screen as an image at the end (since it seems fine to transition from video to image). However, I'm then unsure how to track at what point the attention response is made relative to the attention section of the video which would be required for practice trials feedback (it'd be easy enough to pull the attention response timestamp for the main experiment and check against the video timestamp etc. in analysis).

Any help/suggestions would be much appreciated.

Cheers.

[cratlagh]

I ended up going down the 1 long video followed by a single image and things are working as desired.