I am having performance issues with the wallpaper especially with transitions. I found several old thread on this, but nothing to help me resolve it.

https://www.displayfusion.com/Discussions/View/low-fps-on-displayfusion-photo-screen-saver/?ID=42dee990-19c5-4fa2-b49d-8c6f005979c2
https://www.displayfusion.com/Discussions/View/full-screen-game-fps-drop-when-changing-wallpaper/?ID=a98ffa0b-7e99-430a-a80f-9392b0d438e1
https://www.displayfusion.com/Discussions/View/displayfusion-photos-screen-saver-fade-transition-is-very-jerky/?ID=252e4313-4514-409e-a5d5-15a5de95413f

I know there were several references to not being able to reproduce this and I think I have some ideas on how to do that.

1. Use 3 4k Monitors
2. Use photo jpeg files saved with 100% quality at 4240 x 2385 resolution
3. pick a transition such as disolve

Those jpegs typically of what I get from my a 12 MP sony camera output via Capture One at highest quality to jpeg range in size from 4.7 - 10.5 MB each. That file size seems to be a big issue. If I save the jpg down to 50 or 85 percent the transition performance while still stuttering / flickering due to the low FPS is much better than the larger 5 - 10 MB files. This is leading me to believe this may be an IO issue in how the transition is calculated. It seems this is being calculated in realtime and not cached since the file size is speeding things up. The screen updates shouldn't be an issue as the same number of pixels are ultimately being output to the screen.

I'm not sure if you are manually calculaing the transtion and writing the pixels or using an API to transition, but something is not optimal here. Either pre calculating the transition steps if manual or figuring out the correct API to transition smoothly should be doable.

Machine I am testing this on is way over spec'd (12 cores 4GHZ, Nvidia 3090 (studio Driver 566.36), 128 GB RAM, 5 NVME drives) running Windows 10 with current updates. If you need some test images or settings I am happy to provide those, but this seems to be pretty easy to reproduce on my system with both Span enabled or disabled.

Thanks,
Jon

I tried the new beta today. It seems like a step in the right direction. Sometimes the transitions (I tested cross fade and swipe down) happen smoothly even with the larger higher quality jpg files. However sometimes, they still stutter but in a different way. It is no longer the flashy stutter on each step in the transition, but they periodically pause for an irregular amount of time. It happens more often when two screens are updating at the same time. I am testing with an 8 second interval with the preview button and "use preview mode for this screen saver..." checked. 3 4k screens with "Span Screen Saver Across All monitors" checked

While I haven't seen your code my first guess would be it's a threading / locking / blocking type issue on those times that it pauses mid update. A simple solution might be to add a lock so that only one screen can update at a time during the screensaver updates. This would add a little time to the interval for any screen blocked, but should prevent a host of possible performance and/or stability issues. I saw a couple of times that the transition never completed after 15-20 seconds and moved the mouse to end the preview. Not sure if more time would have resolved that or if there is a hang or deadlock type situation that can happen.

I am happy to test this as much as needed if that helps.

Thanks,
Jon