1.5.3: Unable to open any video files in slideshow

[detal]

XnView: MP 1.5.3 - 64 bit
OS: Windows 10 - 64bit

Cannot open video files (mp4, webm) in slideshow.
https://imgur.com/a/sKKV9B8

Effect: When slideshow is switching from a jpeg, png, gif files to any webm or mp4 file, nothing is displayed and the slide show continues until an image comes up again. Slideshow cannot display any video files.

To reproduce:
1. Attempt to play any video in slideshow.

Actual behavior (bug): When slideshow attempts to display or play a video file, the program displays a black screen.

Expected behavior: Video plays through once or until the slideshow timer causes the next file to be displayed, should be able to cycle between images, gifs and videos. Check mark option for full video length to finish before switching would be optimal.

[philalethia]

Ehm... Aren't slideshows, slides of images, by definition?
Why would you even think to include videos?
...and why would you expect the videos to play through once, rather than stick to the slideshow timer, like everything else in the slideshow?

[xnview]

currently video/animation are not supported in slideshow

[Alamei]

Is the choice not to allow for videos in slideshows a permanent and intentional design decision for XnViewMP, or is re-establishing a few features from the original XnView's slideshow functionality a project that might be considered for implementation in the future? I still use the original XnView for slideshows at this point because I like to intermix still images with short videos (e.g., think of the mix of content you might see on the r/aww subreddit) in a folder and just leave it running on an extra monitor as a peaceful, fuzzy background of kittens, puppies, bunnies, etc. while I'm doing work. I recognize the blending of images and video in a slideshow is a rather unique use-case scenario, but I'm guessing the original poster was coming at the question from the same direction I am, because most of the behavior they describe (e.g., a video playing until the end before moving onto the next file rather than relying on the slideshow timer) is simply how the original XnView currently works.

I completely understand if this use-case is simply uncommon enough that it's not worth the development time to port it over to the new system, but it's the only thing keeping me from moving fully over to XnViewMP at this point, so I thought I would at least ask.