Created attachment 179240 [details] Projectfile Kdenlive 24.12.2 STEPS TO REPRODUCE See Attachments OBSERVED RESULT Glitter/noise by Transform Effekt EXPECTED RESULT No glitter/noise. Same Result as "Position & Zoom".
Created attachment 179241 [details] Picture "Ministry"
Created attachment 179242 [details] Video "Bug 'Transform' erzeugt Glitzern".mp4 I noticed the bug, because the same video became almost twice as large as before (with unchanged render settings, of course). Der Bug ist mir aufgefallen, weil das gleiche Video fast doppelt so groß wurde als zuvor (bei unveränderter Rendereinstellung versteht sich).
This is really weird: I replicated your zoom and it turns out just the other way around. The zoom with the Transform effect is smooth and only with very little banding. But the zoom with the PaZ effect is quite ugly with lots of banding and jerkiness in the movement. I tried with 30fps and 60fps and the results are the same. BTW, in your video, there is some banding in the PaZ version (see the knee pads of the front man). But it is a lot less than the Transform version. Still, I am wondering why my PaZ version is so much worse than yours ...
I had to compress the video a lot to get it below 4,000 KB (render quality “35”). The “Position & Zoom” then doesn't look quite so bad. However, both effects have their own problems. At least everything looks disastrous in the preview. I can't explain the reverse behavior between the two effects in your case. The reported error is very specific 🤷♂️. I had wondered why the complete video suddenly came to 280 MB after the update to 24.12.2 (instead of 160 MB as before). Until I realized that it was specifically due to this image. When rendering, the file size suddenly shot up in certain places and then it continued slowly (with the “Ministry” image).
A few more tests: * Original video (as linked here) is 3.8MB * My first render (using the Generic profile MP4-H264/AAC) with default project settings (using Full HD profile HD 1080p 60fps) is 47.3MB * Transform has banding but is otherwise good, PaZ is horrible * Next test with the same project and render profile but selecting Lanczos for interpolation * File size is 37.9MB * Transform still has some bending, PaZ looks really good (except for some strange noise at the left edge) * Another test with Lanczos and a Vignette effect drops the file size to 27.7MB (go figure) The image file with all t.he dots doesn't lend itself well for zooms or other transformations but with the right interpolation good results can be achieved. The noise on the left edge can be obscured by using a vignette effect (need to adjust the parameters a bit, though).
Created attachment 179314 [details] Video "Backup - Transform before Update (Version 24.12.1).mp4" This is what the (original) movement looked like BEFORE the update to Flatpak 24.12.2 (i.e. version 24.12.1).
Created attachment 179315 [details] Projectfile "Bug Transform erzeugt glitzern (24.12.2).kdenlive" Original movement after update. As soon as the “transform effect” is active in the current version (24.12.2), the image starts to “glitter”. You have to render first because the file size is too large for the attachment.
Created attachment 179330 [details] Projectfile "Bug Transform erzeugt glitzern (24.12.2).kdenlive" Last attachment updated (image renamed).
Ok, so while this is not really ideal, here is a short summary of the situation and a workaround. The issue you are seeing is because I made some changes to the Transform effect to fix shakiness when doing slow zooms. Zooming was not smooth because the rescaling was done with a pixel precison level, so sometimes you could see some "hicups" in the zoom. Original bug is here: https://bugs.kde.org/show_bug.cgi?id=497435 The scaling is now done at a sub pixel precision, which means that if you have an image with a resolution higher than displayed, on small moves you can see some pattern changes. The workaround is to apply a very light blur effect to your image to reduce the patterns, which should give you the expected result. Try for example to add an "average blur" with the default parameters (x=1, y=0) and you should have smooth zooming with no noise.
Thanks for the tip! However, the image is TOO blurred. I'd rather wait for the bug to be fixed.
“Average blur” must be placed ABOVE the “Transform effect.” This information was missing. That's a temporary solution.