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  #1  
Old 11-04-2009, 12:04 PM
Media Man Media Man is offline
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Default which flavor of SMPTE?

I posted this in the HD for Mac forum, but since ext. video sync is involved, perhpas someone here has an answer.

I have to transfer five or six songs from 2" 24 track analog tape to Pro Tools HD.

These are tapes that I worked on over twenty years ago. There is SMPTE on track 24, which was probably used for mixing automation as I am certain MIDI was not involved and no 24 trk. "slaves" were made.

I am not sure if these tapes were striped with 29.97 FPS or 30 FPS SMPTE, and it is not marked one way or the other.

If I sync PT HD up to the 24 track machine using whatever synchronizer the studio has (probably a Linx Timeline), ext. video sync. ref, and a Sync I/O, does it matter if the existing SMPTE is 29.97 or 30.00.

And how do I set up the Pro Tools session in terms of time code?

Mark
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Old 11-04-2009, 01:29 PM
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O.G. Killa O.G. Killa is offline
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Default Re: which flavor of SMPTE?

Why do you need to use the SMPTE at all? If there are no slaves and no midi, why bother with the SMPTE track? It's not going to serve any purpose. Syncing the 2" to protools with SMPTE and just hitting play on the 2" and hitting record in protools will be identical regardless of the timecode setting at this point since you aren't sync'ing anything else to it. So just forget the timecode and do the transfer.
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  #3  
Old 11-04-2009, 01:50 PM
Media Man Media Man is offline
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Default Re: which flavor of SMPTE?

You're probably right, but ....

I wanted to maintain the possibility to transfer any overdubs done on the PT session (new vocals) back onto the 2" tape at a later date, since my client is still living in the 80s.

So the question remains ....does it matter if the unknown pre-recorded SMPTE frame rate on the 2" tape is 29.97 or 30 fps, if I sync up the two. And is my assumption correct that I would set up PT for 29.97 since I will be using ext. video sync?

I guess my main concern is the pitch of the instruments, or is that a concern?

Mark
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Old 11-04-2009, 02:19 PM
Craig F Craig F is offline
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Default Re: which flavor of SMPTE?

How do you want to lock it up?
1) The proper way with the 2" and a synchronizer controlling it
2) the poor man's way and just have Pro Tools chase the raw code

way to check the code is set up a test session set to 30 fps and see if Pro Tools stays locked or drops out, keep changing the frame rate until it stays locked
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Old 11-04-2009, 04:01 PM
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Default Re: which flavor of SMPTE?

Quote:
Originally Posted by Media Man View Post
You're probably right, but ....

I wanted to maintain the possibility to transfer any overdubs done on the PT session (new vocals) back onto the 2" tape at a later date, since my client is still living in the 80s.

So the question remains ....does it matter if the unknown pre-recorded SMPTE frame rate on the 2" tape is 29.97 or 30 fps, if I sync up the two. And is my assumption correct that I would set up PT for 29.97 since I will be using ext. video sync?

I guess my main concern is the pitch of the instruments, or is that a concern?

Mark
Well, 29.97 and 30 are identical. The only difference is 29.97 runs 1% slower, but still contains 30 frames for every second of timecode. This is why 29.97 DF was created, since using 29.97, an hour in timecode is longer than an hour in realtime. Back in the day, I vaguely remember being told to use 30 fps so the hours and mins and seconds match realtime. So it could very well be 30 fps.

Honestly I don't think you'll even notice for a 3~5 min song. If you have protools chase the tape machine it really won't make a difference. Just write down what you use so if you need to fly stuff back onto the tape it will be in sync. The only way you'd run into a problem, even if you didn't have the TC set correctly, is if you needed to sync to something else. But so long as you use the same settings when putting stuff back onto tape as you did when taking stuff off of tape, the actually frame rate you pick is irrelevant.

The only thing that might get weird is pitch. If the PT rig is set to 29.97 and the tape is at 30 fps, the Sync IO might speed up protools by 1% when chasing the timecode. if that happens, you might notice everything sounds a few cents flat when playing back on PT's internal clock compared to when it is sync'ing to timecode. But, technically it shouldn't cause a problem so long as you tune to the track, and not a standard tuner. If the track is a few cents flat...and a singer sings to that, when you sync it back up to tape, protools will play back faster again and speed the pitch of the new vocal tracks up to match the correct pitch of the tape. so again, I don't think you'll even notice a difference.
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  #6  
Old 11-04-2009, 05:41 PM
Richard Barrie Richard Barrie is offline
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Default Re: which flavor of SMPTE?

If there are no automation files or slave reels then there is nothing stopping you re-striping the tape with a known time code.
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Old 11-04-2009, 09:12 PM
evanbenjamin evanbenjamin is offline
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Default Re: which flavor of SMPTE?

>>The only difference is 29.97 runs 1% slower<<

Actually, it's .1%, not 1%.

Your tape is probably 30 frame, because nobody who striped tapes back then for automation purposes resolved their tapes to video ref, which is the only difference between 29.97 and 30.

But if you're going to use video ref, the 30 becomes 29.97 by definition. You can't run 30 and have it be video refed. And you should do it as 29.97, because it makes it easier to deal with potential problems such as dropouts.

-Evan Benjamin
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Old 11-05-2009, 07:38 AM
Media Man Media Man is offline
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Default Re: which flavor of SMPTE?

Quote:
Originally Posted by evanbenjamin View Post
Your tape is probably 30 frame, because nobody who striped tapes back then for automation purposes resolved their tapes to video ref, which is the only difference between 29.97 and 30.
Actually, I did it frequently, because having had video syncing experience, I felt more confident locking two analog machines resolving to video ref, as opposed to "vso" mode which caused the slave to chase time code alone. So I may have just left the generator at 29.97.

Quote:
But if you're going to use video ref, the 30 becomes 29.97 by definition. You can't run 30 and have it be video refed. And you should do it as 29.97, because it makes it easier to deal with potential problems such as dropouts.
Good point. But not entirely accurate ...I think. I clearly remember the good ol' days where I could maintain frame lock for about three minutes or so before the audio and video machines would drift by more than one frame, if the audio machine was striped with 30 and not 29.97.

It's all a blur now.

Mark
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  #9  
Old 11-05-2009, 07:39 AM
Media Man Media Man is offline
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Default Re: which flavor of SMPTE?

Quote:
Originally Posted by Richard Barrie View Post
If there are no automation files or slave reels then there is nothing stopping you re-striping the tape with a known time code.
ta-da!!! And we have a winner. Best solution yet. Why didn't I think of that?

I'll also try the suggestion in the other forum of trying to read the SMPTE using the SYNC I/O, while the analog machine is on internal "clock".

Good stuff jogging the memory.

Thanks.

Mark
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  #10  
Old 11-05-2009, 11:57 AM
lego lego is offline
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Default Re: which flavor of SMPTE?

Depending on the quality of the heads and tape re-striping might cause more leakage of the SMPTE tone to track 23. I'd make some tests on an empty area of the tape.
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