fcp 7 audio/video drift/sync

[Ted Coakley]

Ta-dow, boo-yah, bam, lordy-lord, heavens to betsy, oh my……….

It worked! The conforming to 29.97 in Cinema Tools (“CT”) seems to have solved the audio/video drift problem in FCP7 > Viewer ☺

Even with all my tweaked settings I had set up in FCP7, in trying to solve this (32kHz, 29.975, every 3rd blue moon, standing on one foot, etc), once I imported the CT-conformed 29.97fps clip, it played back fine in FCP7 Viewer (and Timeline/Sequence)

Next, I re-set my FCP7 settings (Easy Setup; Audio/Video Settings >Sequence Presets & Capture Presets; Sequence > Settings) all back to the simple out-of-the-box DV NTSC 48kHz, and my newly 29.97 CT-conformed clip still played back fine in FCP7.

Furthermore, looking at this newly 29.97 CT-conformed clip in Premiere Pro 5.5 (“PP”) and in MPEG Streamclip (both places that showed 29.975 before I conformed it), it now reads as 29.97 in both MPEG Streamclip, and in ONE part of PP (Clip>Modify>Interpret Footage>Frame Rate>Use Frame Rate from File), but STILL reads 29.975 in another part of PP (Window>Metadata>File>Dynamic Media>Video Frame Rate).

Seeing that PP’s Metadata reader is still showing 29.975 leaves me wondering which metadata was actually changed in the file, especially because MPEG Streamclip now shows it to be 29.97, and (most importantly) it now WORKS in FCP7.
At this point, this is maybe over my head, and I guess not relevant to me (since it just works in FCP7 now!), but perhaps useful info to someone else troubleshooting a related issue.

**OH SHIT ALERT**
Right when I was about to post this message, I checked the PLAYBACK of the 29.97 CT-Conformed clip in MPEG Streamclip (works fine), and in PP (does NOT play fine).
In PP, I had already done an edit with the pre-CT-conformed clip (29.975), which PP handled just fine (https://www.youtube.com/watch?v=TjpcvK0pK9c, if you’re interested).
BUT, once I opened PP back up to check its Metadata reader (as I mentioned earlier), both the Clip and Timeline/Sequence audio playback are faulty in ways all over the map (sometimes mute, sometimes fine, sometimes high distortion, sometimes playing audio from other faraway parts of the clip)
I guess that since my PP Clip Import and Timeline/Sequence were based on a clip originally with 29.975 metadata, and that clip that PP points to/references is now the newly 29.97 CT-conformed clip, PP’s audio playback is now thrown out of whack.
I do still have my original pre-(or non-) CT-conformed clip that I can have this PP edit refer to for proper playback (unless someone can now tell me how to get my PP edit to now play nicely with the 29.97 CT-conformed clip), and then use the 29.97 CT-conformed clip if I want to use it on my FCP7.

AND NOW, back to this message about 30 minutes after previous comments in this message, the 29.97 CT-conformed clip is playing back FINE in PP. (except for a handful of edit points now off by 10-15 frames here and there, which I just cleaned up, so it seemingly now works fine with the 29.97 CT-conformed clip)
Go figure!

Hoo-doggie – that’s a lot!

Finally, FWIW, Michael, I didn’t understand when you said that 29.975 is not a real rate, since I’ve read all over the interwebs that true NTSC is not actually 29.97, but, rather 29.975 or 29.976 (I see both mentioned a lot). You saying NTSC is not either of those, but just 29.97?
Just curious.

Big big thanks Nick, Michael, Dave and David – for your help with this!
And to all, a good night!

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[Ted Coakley]

Not so fast on the “good night” at the end of my last post :-/

Now, that newly 29.97 CT-conformed .MOV file doesn’t play in Finder (via Quick Look) – even though it plays fine in Premiere, QT, FCP7, MPEG Streamclip and Cinema Tools.

I’ve tried restarting computer, and working in another Finder window – no luck.
Other .MOV files play fine through Quick Look/Finder. Just the one CT-conformed .MOV file is having problems.

I’d like to have that clip play in Quick Look/Finder again, if possible. Anyone know how to get that working again?

[Nick Meyers]

[Ted Coakley] “Finally, FWIW, Michael, I didn’t understand when you said that 29.975 is not a real rate, since I’ve read all over the interwebs that true NTSC is not actually 29.97, but, rather 29.975 or 29.976 (I see both mentioned a lot). You saying NTSC is not either of those, but just 29.97?
Just curious.”

29.97 the the “real” frame rate
you are perhaps thinking of 23.976, which is a “real” frame rate that often gets abbreviated to 23.98,
or just 24p

[Nick Meyers]

[Ted Coakley] “I’d like to have that clip play in Quick Look/Finder again, if possible. Anyone know how to get that working again?”

try exporting the file from the FCP viewer window, using the default “same settings”
export with the exact same name (basically don’t change anything)
cheek the export, then if it plays fine,
replace the original with the export.

exporting from the viewer window will keep the metadata of Reel# and timecode.

nick

[Ted Coakley]

Thanks, Nick, but I’m not thinking of the “real” frame rate of 23.976 that often gets abbreviated to 23.98 or 24p, as I am as familiar with that as I am with 29.975 or 29.976 being a “real” frame rate that often gets abbreviated to 29.97 or 30p.

Both of those instances are things I’ve thought to be true, and are also what a guy with local transfer house thinks/says (and he has been transferring NTSC (and many other formats) for 30 years now).

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?

[Ted Coakley]

Alright, Nick, here’s what I did, thinking this is following your suggestion.

1. Imported file that no longer plays in Finder/QuickLook, but plays well in everything else, into FCP 7 Browser.
2. Opened file in FCP7 Viewer
3. File > Export > Quick Time Movie
4. Settings: Current Settings
Include: Audio and Video
Markers: None
Recompress All Frames: DEselected/UNchecked
Make Movie Self-Contained: Selected/Checked

After about 5 minutes, there is a new .MOV file, same image size and Duration as the original.
The new file is 29.284GB, vs 29.277GB original file (so, pretty close).
And the new file also does not play in the finder/QuickLook, just like the original does not.

[Michael Gissing]

[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.

[Ted Coakley]

Thanks for the math, Michael.
Yep, I see that .999 x 24 = 23.976, and .999 x 20 =29.970.
So, I get it (with the new knowledge that 0.1% was the intended/desired frame rate shift).

I also get it when you say that AE allows 23.976 setting (and I’ve mentioned that Premiere does, as well), unlike other NLE/VFXs, but, also as I’ve mentioned, my initially problematic-for-FCP7-Viewer 29.975 .MOV file, was from a FCP 7 Import to an FCP 7 export.

Hopefully, this clarification may be helpful to anyone that reads this, who might have some insight or explanation.

However, this leaves us (or at least me) wondering a) how the FCP7 export made a 29.975 file, and b) why some people think 29.97 is actually 29.976 or 29.975.

[Michael Gissing]

I’m one of the lucky many that live in a 25fps world (actually most of the TV world is 25fps) but have had to deal with the small but influential 29.97/ 23.976 world and sort out the math to deliver speed corrected pitch correct audio mixes over feature length programs.

[Mark Suszko]

In all the banter about frame rate, anybody check and match the audio SAMPLE rates?