Under the EDIT menu, select PROJECT SETTINGS.
If 1:2:1 deflickering is turned ON, try turning it OFF. I sometimes use this if I’m doing something like rolling credits. It makes the overall frame a bit fuzzy. I mostly keep it turned off unless I need to soften some annoying flicker. It’d be nice if this option could be restricted to individual layers rather than the whole project.
I usually leave better quality field rendering turned ON. But if you aren’t working with interlaced fields then you probably don’t need this.
You can also try switching between 8bit and 16bit colour depth.
Unless you are working completely uncompressed though, you will experience some degradation in image quality with each level of processing from media aquisition to final product, just like dubbing an analog tape over & over.
Jaeson