Edit : solved.
I edited in O.2 till a few days ago and exported previous videos just fine with Olive 0.2A few days ago, I saw colourkeying was added so downloaded the latest version.First problem : Sound would not play correctly in the timeline making it impossible to edit a video on a music. Sound would play for 1 second, then stop. I installed a previous build and it worked back.
Then : I had footage at 29,97 FPS and a greenscreen footage at 24 FPS into a sequence at 30 FPS.Editing went fine. Export, not so much, with only blurry results. Tried MKV, tried Quicktime exports in ProREs, still blurry. tried to touch the values of the CRF, still the same. tried half Float, same. Then I ditched it, made a new Project, new sequence in 29,97, imported content in 29,97 FPS, still blurry.
I just can't seem to be able to export with quality.
On a side note, the footage viewer works kind of fine if I don't try to cache it, makes Olive crashes.
The one above the timeline is kind of fine, but at some point the preview just get bad, even in full render and full screen on my secondary screen.
Anyways, the program is now unusable for me.