The reason for this is that Premiere Pro hands us (Color Finesse) an 8-bit version of your image when dragging and when inside the full Color Finesse UI. Because it's an 8-bit RGB image, overbrights get cut off, and there was an extra YUV->RGB conversion performed.
When rendering, and when you stop dragging, PPro gives us a floating-point YUV image, which Color Finesse is happy to process without any problems clipping overbrights. But because the image format is different, there may be visible differences, depending on the footage.
I don't really have a good solution for you. There have been some changes in the PPro CC plug-in API that may help us; we're currently investigating how we can take advantage of that.
If it helps, the result you see in PPro when not dragging is what will render to your final output.
Thank you, Bob, for answering. And I would also would like to thank you for creating such a convenient instrument for After Effects (cause you see - I seem to can not use it under premiere pro).
I guessed that in dragging mode PPro tried to optimise rendering in different ways clipping it from all the sides etc. But the problem is that all is vice versa: I do like the result in dragging mode and it's the same as in full Color Cinesse instrument and I can see clipping in stop cursor preview mode. Unfortunately there is no any difference on Ppro YCwaveform in this two modes (dragging, stop cursor) so I have to load images from footages (from Composite Video view).
That's why It does not help that the result I see in PPro when not dragging is what will render to my final output (maybe I'm wrong, maybe highlights are not cut but just more reddish...but I can feel more difference in video - the first one looks much better).
Do I correctly understand that dragging mode differs from stopping not just in that 8-bit image is handed instead of 32-bit but also that the first one is RGB but the second one is YUV (there are no YUV modes in Color Finesse full interface in some reason)? So is it possible that clipping happens with 32-bit YUV image? We could test your plugin by feeding it my original video footage (you should test it in PPro) - if you wish - and you could see - why there is difference (I understand that it may take some time so I seem to not wait to the results and find another way of color correcting though I very much like Color Finesse).
So - I'm sorry. In this case the problem seems to be exactly in Color Finesse? But anyway I don't understand why not implement Color Management in PPro such as it's done in After Effects or maybe even better by having several options. I think that sometimes you'd better have several options instead having no ability to do something.
P.S. Bob, I also have a suggestion for your plugin - it's kind of UI improvement. It's a good idea to have the ability to reset each option (each slider) by just double clicking on it's name just as it's done in Lightroom.
Premiere Pro handles AE-style plug-ins differently than AE itself does. I understand why in most cases, but it can still cause issues like you're seeing. Whether handling things differently is a bug or not is not worth arguing about; the important thing is to minimize any side effects.
The difference you're seeing is because--for performance reasons--Premiere Pro sends the smaller 8-bit RGB images to plug-ins when doing something interactive. This helps keep things realtime. But once you stop interacting, it passes the more accurate YUV float image to the plug-in. Additionally, when Color Finesse requests frames from PPro when in the full UI, it is always given 8-bit RGB (this part I consider a bug).
So I understand why there is a difference, but not why you're seeing the difference you are.
Whether PPro sends the plug-in YUV integer, YUV float, or RGB float to the plug-in depends on the codec in use; Color Finesse can handle all those formats. Because of this it would be good to be able to test with your footage. The possible issues could be 8-bit to float conversion, YUV to RGB conversion, or some combination of the two. Being able to test your specific case would help.
You can send a short bit of footage to us at support "at" synthetic-ap "dot" com. Also send along your Color Finesse correction settings. We probably can't get to it until next week but I would like to definitively understand what's going on.
Regarding resetting a single slider: if you command/control click on the text it will reset the parameter. Resetting by double-clicking is a good enhancement request though.