24 fps ProRes HD to PAL SD without blur

[Michael Gissing]

Nick is a freelance editor in Sydney. I have my own post facility in rural Tasmania after moving from Sydney five years ago but have worked with Nick on docos and music DVD projects. I mostly do documentary sound post, grading & online.

With Logic you really need to be able to dial in the correct speed adjustment for sync. Programs like MPEX3 let you select exact 24 to 25fps. Speeding up by 4.1% should give correct sync for most programs. If it is a really long program 4.16% is closer. Also reimporting the audio file back into FCP you need to make sure your Easy Setup frame rate matches the sequence otherwise FCP will stamp the wrong frame rate an make the audio drift.

Best is to find a facility with the software I recommended. There may be other good software as well but they are the ones I have personally used and know work well.

[Nick Meyers]

i would suggest you listen to your 25fps file, and see if the sound is unacceptably bad.

the only people who would notice the shift are those who know the actors very well, and those with perfect pitch.

nick

[Ben Knight]

Hi Michael,
Well, guess what… I tried again with Logic. Based on your hint there, I took the original, un-sped audio file (from the 23.976) and I sped it up with Logic Pitch and Time Machine. But…I sped up by using:
25/ 23.976 = 1.042709, so i entered 4.2709 in the % speed.

Then, made sure FCP Easy Setup was 25p and 48k.

Didn’t bounce from Logic, just coped the NOW MODIFIED source aiff file (Logic destructively changes the audio file).

Brought that file into FCP, matched it with the conformed video (conformed to 25p from Cinema Tools)… and it worked! I exported the file and sync was perfect.

To me it sounds pretty damn good. Does the quality of the actors voices sound exactly the same, just a tiny bit faster? Well… maybe not EXACTLY the same, but I don’t have audio from one of the other programs to compare.

Anyway… it’s a lower budget option, and I still may go ahead and use it.

Am I missing anything in my calculations? I know you said 4.16%… but 4.2709% really seemed to work: the file matched the conformed video exactly, down to the frame…..

?

[Michael Gissing]

My calculation were on true 24 to 25 so you worked it out for the 23.976 properly. The sort of artifacts to worry about are watery sounds or slight glitches/ stepping in sustain music notes.

The only other thing is stereo phase. To test that is OK pan L&R to center, change phase 180 degrees of just the right channel and listen on headphones. You can’t do that in FCP but Logic should be able to do a phase switch on one channel. When you listen, all the mono things like dialog should totally disappear. If you hear bits then the phase between channels is not correct. This will be an issue for mono compatibility and also if the stereo is decoded by a Dolby Pro Logic surround chip (common in amplifiers and may TVs.

[Ben Knight]

Thanks Michael, plenty of good info there.
In my case I had all original sound assets, so i bounced dialog and foley to a mono track, then added the orig music (unstretched) back into the FCP timeline along with the mono track.
Thanks again.