Problem syncing drifting audio from old 16mm footage in Premiere CC

C

Charles_I

New member
Hello,

I'm new to the forum, but excited to see what goes on here. I am a graduate of a 1970s film production University program (York University, Toronto). Over the last few years I've had all the negative for my films professionally transferred to digital high resolution files (saved as .mov). Most of my films weren't taken to the print stage so I will have to literally re-edit them and manually sync every shot again. Not looking forward to it :-)

However, one of the films was finished as far as creating a 16mm print. I thought I would start by editing this one first since it's in the final cut and final mix stage. I had the 16mm A & B negative rolls used to make the print transferred -and they are astonishingly good quality compared to my VHS transfer from the print. There are two video files with blank white content where the other roll is the picture. I've cut these into individual shots in Premiere and have started assembling them into one video track.

The original mixed 16mm mag stock soundtrack was also professionally transferred in a studio specializing in audio file restoration. There is a standard countdown SMPTE sync point at the start of the film in the video and audio, but because there is no longer any camera sync pulse or any other means of locking the speed the audio drifts out of sync after about a minute.

The film is about 17 minutes long (a b&w take-off on Rod Serling's Twilight Zone and Night Gallery). The transfer frame rate is 23.976 - the audio is: Source Audio Format: 48000Hz - 16 bit - Mono, Project Audio Format: 48000 Hz - 32 bit floating point - Mono.

I have searched the online tutorials but I can't find anything that describes this particular syncing situation. I have tried adjusting the Speed/Duration of the audio but it doesn't work.

So here's my question. I can imagine I have these options but I'm not sure which one is the correct way to go about this.

1 - create short in out audio segments (perhaps even cutting the audio) where there is no sync dialogue and somehow stretching (speed/duration?) them so the next segment is in sync.

2 - adjust the speed/duration of individual video shots to match the audio.

Both of these sound massively time consuming. I don't suppose any of Premiere's magical automatic fixes will do this. I'd appreciate anyone's experienced feedback.

Thanks
Charles
P.S. In the event that this is a peculiar Premiere problem, I also have PowerDirector 13, but my previous experience with PowerDirector 11 seemed to indicate that Premiere is a better choice.
 
The problem is that the old sync system is missing - so you have two media sources that drift - which back then they all did, and unless they were crystal locked, then it's going to take time and patience. Sepmag - blimey that's a term I've not used for a long time now was pretty good, but unless you can find the orginal kit and do the transfer again, then you are a bit stuck.

That said, if it was me, then I'd use something like Cubase (but Logic will do the same thing) - you bring in the video file and it becomes the master. The audio file is then tempo mapped to it. You can extend and shorten the audio clip to try to match it to the video. The process has auto modes but probably won't work with the clip you have as it's music based, and speech and effects will mess it up. I would break the audio down to short lengths - about half the duration of the track before you hear the thing slipping, then I simply slide the tracks around, and put small crossfades over the joins if they crunch, which most will. It's going to take ages, but will work.

You may of course be lucky and find the rate of slip is constant - which means you can simply shorten or lengthen the audio clip linearly which might just be a case of adding a small percent to time, while keeping pitch constant. Audio software is where you need to be looking.
 
Thanks Paul,

I don't think it was even crystal based. We used the standard Nagra recorder with Ariflex cameras and a sync cable that put an audio sync pulse from the camera onto the edge of the tape. There were no video cameras then (except for TV studios) so the old fashioned film way was the only way - hard to imagine today.

Of course this system was flawed - both video and audio were probably never steady. It depended on the stability of the electrical current and if there was a shot outside using a battery belt in sub-zero weather it was even more variable. Even if I had the original kit there is no way to sync it digitally. The time code on the film is out of range of the digital transfer (I asked if it could be included at the time and the answer was 'no') but it wouldn't be much good anyway without a way to sync the audio track to it. Back then the audio was transferred to a magnetic 16mm sized tape with sprocket holes so it would align perfectly with the sprockets on the film (explanation is for others reading this that don't know what I'm talking about.)

Cubase is rather expensive for a single use like this (and I'm not on a MAC for Logic). But thanks for the tip to go for the audio rather than mess with the video. I wonder if chopping up the audio and adjusting each clip of it in Premiere would work. I don't think it goes out by very much within each scene, so I'm not worried about speed variations being audible. It's not actually music based, as you say. There are some sequences with music but most of it is just dialogue and sound effects and most of the music cues are not critical to an exact frame.

How does changing speed/duration in Premiere differ from changing the speed in Audition? Since they are linked together which one is more incremental? If anyone else has any other (inexpensive) software tips please let me know.

Thanks
Charles
 
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Your film was shot at 24fps and transferred at 23.976. The mag track should have been slowed down by .001% to match.

BTW, you might be able to adjust the audio with Audacity
 
Last edited:
arniepix said:
Your film was shot at 24fps and transferred at 23.976. The mag track should have been slowed down by .001% to match.

BTW, you might be able to adjust the audio with Audacity
Click to expand...

That was my first thought as well. 24 film vs. 23.976 video. Note that in Premiere, when you try to move your audio clip left or right, the default is that it moves in frames. So if working in a 23.976 Sequence, you can only adjust the audio clip in increments of 1/24 of a second. What you can do is click the little menu icon at the top right corner of the Sequence window in Premiere and that opens a drop down menu. Click on "Show Audio Units". This will change the time marks on the timeline to match the audio sample rate, for example providing 48000 increments per second rather than 24!!! Provides almost infinitely fine adjustment. Just zoom in as far as you need to for precise control.

Thanks

Jeff Pulera
Safe Harbor Computers
 
Finally getting back to this. Thanks for all your suggestions. The 24fps vs. 23.976 definitely explains it. I should have thought of that. Audacity seems to work changing the speed but my first attempt at .001% was way out. I'm going to try again using 0.1001% - after using an online calculator to get the difference in percentage of those 2 numbers, that's what it came up with. My math is a little rusty. I'll let you know if I can get it to work.

BTW this is a stupid question but I can't find a reference anywhere to an audio nudge key command. Is there one in Premiere CC for PC? Using the arrow keys doesn't move the audio timeline and dragging it doesn't seem very precise.

Thanks
Charles
 
Hard to believe it was January when I first posted this. I finally have the 16 minuite + film completed in Premiere CC and it's all in sync. I was able to use a poor quailty transfer of the final 16mm print to VHS tape as a guide. I matched the speed of the audio after a lot of trial and error by setting it to 100.01%. For the video I managed to sync it by adjusting the speed of each shot so that the cut on the VHS version matched the same exact frame on the transfer. The speed of the video clips varies from roughly 100% to 90% (too many shots to remember the maximum and minimum exactly). A great deal of them were OK at 100%. I now have the entire film perfectly in sync in Premiere.

The problem is no matter what setting I have tried to Export the film it is not in sync. Right from the first synced shot which is only 20 seconds in, it goes out. I have tried exporting to MEG2-DVD, and Windows Media. I've tried using "Match Sequence Settings" and/or "Use Previews". I've tried deleting the rendered files (as suggested in other site's posts on this). Nothing works so far. Any ideas out there? I would like to burn a DVD for television use.

Great that's it's done - but kind of useless if I can't get it out of Premiere.
 
I don't know if Premiere has an edit tool comparable to Lighworks fit to fill command. I have used this to sync double system audio that drifts slightly over time with video.
In Lightworks, I mark in points of the video and audio so they are in sync at the head. If I expand the timeline, the audio clip will show as slightly shorter or longer than the video. I mark separate out points at end of video and end of audio. I cut the audio track only from the timeline to the clipboard. Using the fit to fill command I reinsert the audio to the video clip I/O marks and the audio track is stretched or shortened to match. Voila, perfect sync. Usually the drift is so gradual that there is not enough difference to change pitch or speed of the audio noticeably.
 
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