Quality loss when combining two transform

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1

I need to combine two transforms (one to scale and set the initial position, and one where I copy/paste keyframes from a tracking object).

However, as I reported in 488742 – Combining two transform result in huge quality loss (link added by a mod) this results in an important quality loss as shown in the attachments.

Any workaround?

2

You don’t say what format or resolution your project is using, but your example png is only 670x319, so I would expect rendering that upscaled to even 1080p to start looking pretty ghastly?

3

Yes the overall project uses a 1080p resolution. In the demo I just created a new project without even changing the resolution.

4

You’re getting burned by the confusion that occurs when you add a clip that’s a different size to the project frame. kdenlive will try to automatically make it still fill the frame. Then when you start doing things like adding a transform it turns into a confused mess as to which coordinate system it’s actually working on and what the “size” percentage is actually relative to (doubly so if the aspect ratios differ and X was rescaled differently to Y). If you add another transform, that all just compounds.

There’s probably a whole bunch of ways that ought to be improved, but you are starting on pretty fragile ground if you’re mixing different source formats.

Right now, my best advice is if your project is 1080p, and you want effects to behave predictably, make your source image 1920x1080, pre-scaled how you want to fit it into that frame, before you add it to the project. Then you can layer transforms and other effects as deep as you like and it should all work as you expect.

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5

Oh thanks a lot, I can confirm this workaround works, so doing:

$ convert 2_to_one.png -resize 1920x1080 -background transparent -gravity center -extent 1920x1080 2_to_one_1080p.png

before importing solved the issue for me… but it would be way simpler and less confusing if KDEnlive could do it by itself, or figure out a cleaner way to address transforms. But I guess this has to continue on the bug tracker.

Anyway, thanks!

6

This is on the Mid Term Roadmap :wink: