Wallpaper stutters when trying to loop a video

[allanlf]

I created a silly animation in Blender.
I originally intended it to play at 4K, 60FPS, though that caused the video to black screen at the very end of the loop before starting over.
I thought maybe I had gone overkill with the bitrate, but even after setting the resolution to 1440p and the frame rate to 29.97, while rendering the video at a bitrate of 10, it still stutters.
It doesn't black screen for a few frames like before, but it still produces a very noticeable stutter and I'm wondering if there is any way to prevent that.

[Tim]

What compression are you using? The stutter you describe is indeed usually related to the codec but we are not entirely sure either what causes it sometimes to happen but you may be able to eliminate or minimize it by tweaking some other codec features or using a different encoder. Try to export the video raw and then use a free tool like Handbrake to re-encode it with H.264 just to see if that might help.

Generally we recommend building video-based wallpapers in a way that the loop happens in a moment with very little to no movement, so that any stutters are minimized.

Keep in mind that Wallpaper Engine uses the Windows Media Foundation for video playback, so the stutter essentially comes from Windows / the graphics card driver itself. Some third-party video decoders do not have this issue but we cannot bundle them with the app for legal reasons, see this help guide for example:

https://help.wallpaperengine.io/en/videos/lav.html

It's "somewhat annoying" however, since affected users would all have to install it.

[allanlf]

Sorry if this reply is structured weirdly, because I'm just going from point to point without much cohesion.

I'm not sure what exactly you meant with "What compression are you using?".
For context, I have exported the video with Premiere Pro, because Blender kept corrupting my image sequence for unknown reasons. In Premiere Pro I just have to choose a "format", and this is kinda confusing, because it doesn't make a proper distinction between codecs and containers. Anyway, what I often do is just choose H.264, which causes premiere to automatically spit out a .mp4 file.

What do you mean with "export the video raw"? You mean like, using a lossless format like quicktime?

Do you mean to say that I don't need to sacrifice resolution, frame rate and bitrate if I can get the codec "fixed"?

And finally, my video has a looping linear camera motion, meaning it never stops and moves at a constant speed, so what you suggested is not an option.

[Tim]

So basically, yes, H.264 compression inside an .mp4 file is what we recommend and it should generally work well.

But there are different ways to generate these types of files and my suggestion is - as you said - to export the video lossless instead and then try to turn it into an H.264 inside an .mp4 file with another tool such as HandBrake.

This approach can help to make it better even with similar quality settings as Premiere Pro uses - it could literally just be a slight difference in the way that these files are encoded that you will experience less stutters. We are not sure what causes video files to stutter in Windows like that, so I cannot give any super specific advice other than that, it's worth a shot though.

[allanlf]

Okay, from what I have noticed those instances I mentioned of black screening was a mistake I made with the video itself, and it seems like I did manage to minimize the stutter, but I can't tell for sure because the entire video looks rather choppy.
I can confirm the video sent to wallpaper engine plays at a perfectly even 30 FPS, but what I screen recorded from my desktop plays at a very inconsistent frame rate, after analyzing it frame by frame.

This might be unrelated to the main subject, but are pre-rendered videos not the best way to work with Wallpaper Engine? Most of the Wallpapers I see seem to be still images that were animated within the Editor itself and it seems to be the reason why they don't seem to use much of the GPU despite being in 4K. Is that the style I should aim for with whatever I decide to make next? Or would pre rendered videos generally still consistently work as long as there isn't too much movement going on?

[Tim]

Generally, video wallpapers should and do work fine. There are some edge cases where video wallpapers are better, basically anytime you really just have a complex loop with some heavily pre-rendered content that would not be viable in real-time rendering. It is also good for people who are experts with third-party tools and do not want to learn how to use the Wallpaper Engine editor.

For us, what we really focus on is the editor and Scene wallpapers. I don't want to call video wallpapers an "afterthought" but the focus of the app was always to build a high performance engine and I think it is fair to say that Wallpaper Engine is comparable to a game engine that we continuously extend with new features. For video wallpapers, there is not really much or anything at all that we can do at this point - they are videos, they play and they loop. We have some advanced video settings in the "General" tab of the Wallpaper Engine settings that can help with issues like the ones you described, but that is about it.

If you want to check out some of the more advanced features of the editor, be sure to look at our docs, though the particle systems pages and audio visualization pages are still work in progress I am afraid:

https://docs.wallpaperengine.io/en/scene/overview.html

There is a bit of a learning curve but especially with the features we have added in the last two years or so, you can do some crazy things with the editor once you get past the initial learning phase. I actually think if you just scroll through our news and read the changes, you can get a pretty good idea of what features exist that you might not be aware of:

https://steamcommunity.com/app/431960/allnews/

All of that said, if you have now created some video wallpaper and it just does not loop right, you could also try and share it with us (upload it as private to Steam for example, we can still see it) and see if there is anything odd about the file.