In Sirils developer version since a few weeks I observer the following. When opening a single image with “open”, the image displays all right. However, when this image is part of a sequence, I select this sequence and open the image from the sequence list, the image seems to have some “tiles” with a rather grainy appearence. Here is a example screenshot:
I am using Debian Trixie with kde plasma. Also tried a fresh compile from sources. All mandatory and optional dependencies were fullfilled.
meson-log.txt (227.0 KB)
Here are some new findings. The problem seems to me to be closer to the graphics card and graphics driver or rendering, although I’m not familiar with this topic. When I switch between images in a sequence, exactly these kinds of patterns with tiles appear for fractions of a second, some of which are grainy. Sometimes and randomly, however, these seem to persist.
Maybe this problem is unrelatated to Siril. I am using the build-in graphics of my main board, which is no problem with two 4k displays. But I do not have a GPU. Has something changed in Siril 1.5? I’ve been compiling Siril myself for 3 years now, and this is the first time such problems occur.
When using Siril 1.4.4 as an app image, I dont see the behaviour with the transient and sometimes permanent grainy tiles, so there must be some dependency on the Siril version or the way it was compiled
Hi, I’m making progress with this but please could you confirm a few things:
- What is the sequence frame size (width x height, in pixels)?
- What is your monitor resolution?
- I assume you haven’t touched the display cache budget setting in Preferences / Performance? Please could you change this to 512 or 1024 MB and confirm whether or not that makes the issue go away? (To be clear, I’ll fix it properly even for smaller display caches, this is just to confirm my diagnosis.)
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This pics are 9511x6379 pixels.
I have two monitors attached, 3840x1600 and 2560x1600
Ah, and it looks like setting the display cache in Siril 1.5. to 512MB fixed the problem. Wow. In Siril 1.4.4 I dont see this parameter.
No, the parameter is new: the image rendering mechanism in Siril 1.5 is very different and partly GPU-enhanced, enabled by the transition to GTK4. For large images only the visible parts of the image are rendered, on a tile-based system, and then the GPU handles arrangement of the tiles in a GtkSurface which makes pan and zoom more efficient. The bug itself looks to be due to running out of cache to hold the next-MIP-up render, which is held in order to make zoom smoother. So increasing the cache is a short term fix, but improvements to the tile / MIP eviction strategy are the right fix.
Thanks for the detailed explanation. Helps to understand what is doing on “under the hood” of Siril. I am glad to have a good workaround now and to have helped a bit to further improve Siril. Keep up the fantastic work 
Just a quick follow-up, is the sequence mono or is that just one of the single-colour viewports on a RGB sequence frame? Also, is the zoom level zoom-to-fit? What zoom shows at the bottom-left of the image?