Hello, I'm trying to slowly (more than a minute at 30fps = at least 1800 frames) reveal one image on top of another one, left to right.

The movement should allow for "decimal" progress, meaning that it needs to be sharply cut off but if the x-position of the wipe happens to be between two pixel values, there should be interpolation and not just rounding (something that can happen when using Composite for keyframed movement - https://www.youtube.com/watch?v=bMc8Z8j1hsQ ) - Although this would actually be a bonus, as currently I'm not able to even get the transition to work pixel by pixel.

Unfortunately the PGM transition masks contain 256 gray values, meaning that with 1920x1080 HD, every 7th or 8th pixel gets revealed each time the transition wipe has progressed far enough for the next grayscale value. In a 60 second video at 30fps that should mean that aproximately every 7th frame an additional piece is wiped/revealed (~4fps). Here's a video: https://www.youtube.com/watch?v=z4vdwQ8SvI8


Wipe without smoothing


Wipe with smoothing value "1"

Using smoothing helps the effect but the blocks are huge. I need a sharper/clear-cut for this though.

Unfortunately the crop effect doesn't support keyframes and might also not support decimal numbers.

The wipe (luma) Transition supports "PGM files up to 16 bits" but what does that mean? Is it possible to create a PGM image that has 16 bits of grayscale values? Or can a gradient be created using all colors that would simulate a 16 bit gradient with 65,536 steps? How?

Would be glad to hear if somebody has a solution, thanks for reading!

Updates: I ran into a similar problem in Shotcut ( https://forum.shotcut.org/t/smooth-slow ... sition/297 ) but on the other hand was able to achieve my goal in Blender ( https://youtu.be/oS8n-9PS-Co ) - still would be nice to be able to do it in Kdenlive

I was able to find a workaround.

added a white color clip to a track above both other tracks, removed the transition between the images and added a "alphain" transition between white track and the track beneath.

The white track got a "Position and Zoom" effect applied, which was keyframed to move from 0 (first frame) to 1920 (last frame)

Depending on which image is supposed to blend into which other image, change the order of the two images on the two tracks they occupy.

Screenshot: http://i.imgur.com/kVuWBCu.jpg

Render result: https://youtu.be/MmZl2fRrq9Y

Render time (1m video) was 8 minutes, compared to 4 minutes when using the - in this case - unsuitable wipe transition.