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Topic: Frame by Frame Telecine Sound Syncing?
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Ty Reynolds
Film Handler
Posts: 93
From: Calgary, Alberta, Canada
Registered: Nov 2015
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posted June 20, 2017 04:05 PM
I now use a scanner that also captures synchronized audio, but this is how I used to do it:
Make sure the film has plenty of leader at the beginning, and at least two inches of leader at the end. Scan and process the film. I was using Moviestuff's Workprinter and Retro8.
Then I run the film again on an Elmo ST1200 with a camera aimed at the projected image. Just a basic point and shoot set-up, the image quality doesn't matter. The video portion will just be a guide track. The audio is fed from the projector to the camera's line in, and both audio and video are fed from the camera to the computer via firewire. This is recorded in my editing program, Vegas. You could also record on tape or card, and then import.
Place the scanned footage on the timeline. Trim the leader to the first frame of film. Trim the end leader to the last frame of film. Calculate the exact number of frames.
Place the second film capture under the first in the time line and trim to the first and last frames. Line up the first frame of each capture. Calculate the exact number of frames in the trimmed camera capture.
The number of frames between the two captures will never be an exact match. Calculate the percentage difference. I then open the audio file of the second capture in an old version of Adobe Audition, although I think something like Audacity will do. Use the Stretch/Pitch function to stretch or shrink the audio file to whatever percentage you've calculated will result in the same number of frames as the trimmed first capture. Save the file.
In Vegas, the saved audio file then automatically replaces the original, but does not change in length. Shorten or lengthen the corrected audio file to line up with the end of scanned film. That should also be the end of the saved audio file, and your audio should now be frame-accurate.
Virtually all the digitizing I do is of home movies, and finding suitable reference points within the film is not always easy. I have better success if I can establish the absolute first and last frame of film. Tail ends of 50-foot reels are often mangled, so a trim with a bit of leader added gives me a clean final frame.
The Elmo gives me reliably consistent speed, provided I let it warm up with about 5 minutes of film. Since I have to speed-correct the audio file anyway, I run the Elmo at 24 fps, even though most home movies were shot at 18 fps, just to save time. In the end, the pitch will be correct. Occasionally, a 400-foot reel of film will still require a frame or two adjustment here and there, but for the most part no other correction is necessary.
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Winbert Hutahaean
Film God
Posts: 5468
From: Nouméa, New Caledonia
Registered: Jun 2003
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posted June 21, 2017 12:01 AM
Hi Janice,
I am not sure in your case, but I prefer to upload what I did here:
https://youtu.be/V9GNTBoAx74
The original song of Bryan Adams "Straight from the heart" is 190 seconds at normal BPM 83.
This video shows the Virtual DJ 7 which can really produce a distorted sound when we change the speed.
But on the newer deck, Virtual DJ 8, we hardly hear that.
So on the lowest speed BPM 56, the duration becomes longer, i.e 285 seconds or 95 second slower of the original song. And when it is on BPM 112, the duration becomes 143 seconds or 47 seconds faster of the original song.
If you are familiar with Bryan Adams', voice you can hear that no matter on BPM 56 or BPM 83 (normal) or BPM 112, you still recognize his voice, not a Donald Duck or Micky Mouse pitch.
Hope that can explain.
--------------------
Winbert
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Ty Reynolds
Film Handler
Posts: 93
From: Calgary, Alberta, Canada
Registered: Nov 2015
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posted June 21, 2017 12:22 PM
Janice - I just used the Cinecap Velocity program for processing the files to the correct fps. Compression doesn't enter into the equation. Neither does pitch correction. If, for example, your film is 10 minutes long, your finished video file will be 10 minutes long, regardless of compression. Once captured and manipulated, your audio file also will be 10 minutes long. Same playback speed, same pitch.
When you capture both the flickering image and the audio directly from the projector, you are creating a visual reference for the audio. By establishing the first and last frame of both the speed-corrected scan and the projector capture, and making them line up, you are basically telling the audio file, "You're supposed to start here and end up there. Make it so."
This will work even if the speed-correction of the scan isn't absolutely perfect. If your 10-minte film becomes a 10 minute and 3 second file, your audio file will end up at 10 minutes and 3 seconds. The difference in pitch in this case is negligible.
All that matters is that the projector performs at a consistent speed.
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I've been doing video editing for years...but this was pretty challenging. I probably should have just re-recorded the audio with another projector...but I was stubborn and was going to get it to work. It only took me to 2am to get it in sync.
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