[Ted Coakley] n”Are you saying that the transfer house and I are wrong in our thinking that NTSC 29.97 or 30p is actually 29.975 or 29.976, and that it actually is just 29.970?”
Basically yes. A shift in frame rate by .1% was decided on all those years ago. Grab a calculator and subtract .1% from 30 and 24. You will see that 29.97 is correct and 23.976 is too. 29.97 is not an abbreviation. The only software that I have heard of that can give an incorrect frame rate like 29.975 is After Effects which is why I was curious if it had been used in the conversion to ProRes. With AE it is also necessary to spec 23.976 not 23.98. All other NLE and VFX software that I know of give options based on actual frame rates. AE allows for user defined frame rates and you have to be precise to the decimal points.
What FCP was trying to do to resolve the issue was varispeed the sound to play back 29.975. However the video rate couldn’t be shifted because a frame is a frame. FCP trying to be helpful with changing audio speed has been a constant issue with what was seen as a feature of the program has really behaved like a bug for many of us over the years. Hence people will ask about sample rates, bit depth and the killer problem of having a different default easy setup frame rate. That one really is a bug which will never be fixed. It only affects audio only not a QT file so I knew your issue was incorrect frame rate metadata.
I have no idea why the corrected file is now causing grief in Finder. It is possible that somewhere in the OS the original files metadata was stored and now it doesn’t cross reference.