Capturing Beta Tapes

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Max Winik

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Capturing Beta Tapes

PostThu Jun 08, 2017 8:07 pm

Using my UltraStudio 4K, I am trying to capture Beta tapes. I am playing back the tapes on a Sony J-30SDI. The tapes playback at 29.97fps. With Media Express, I am able to capture at that frame rate but I want to capture these tapes at 24 fps in order to sync the audio from the tape with my 16mm film scans that are 24fps. Does anyone have any suggestions?
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JPOwens

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Re: Capturing Beta Tapes

PostFri Jun 09, 2017 6:56 pm

Max Winik wrote: I want to capture these tapes at 24 fps in order to sync the audio from the tape with my 16mm film scans that are 24fps. Does anyone have any suggestions?


Capturing at 23.98 is not necessary or desirable to keep sync. If your film scans are indeed at 24.0000 fps and not 23.98, you will have a pull-down problem... but if the film basic frame rate is re-defineable in some way, like changing the metadata framerate of a dpx sequence, then you don't have any concerns other than the 1000/1001 speed change.

But in every other sense, 29.97 and 23.98 are compatible for sync purposes in real time.

jPo, CSI
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Colin Barrett

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Re: Capturing Beta Tapes

PostSat Jun 10, 2017 12:00 pm

To achieve what you're seeking to achieve you will need one of the Teranex systems to do an inline conversion to 24fps. However, as JP points out, you'll encounter pull-down issues even though the Teranex is pretty good at coping with this.
Blackmagic Teranex 2D, Ultrastudio Express, Intensity Shuttle (Thunderbolt), Two H.264 Pro Recorders (Mac OSX) & lots of old VTRs used for digital archiving of legacy video formats for major libraries, broadcasters, universities and public archives.
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Andrew Kolakowski

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Re: Capturing Beta Tapes

PostMon Jun 12, 2017 9:36 pm

Max Winik wrote:Using my UltraStudio 4K, I am trying to capture Beta tapes. I am playing back the tapes on a Sony J-30SDI. The tapes playback at 29.97fps. With Media Express, I am able to capture at that frame rate but I want to capture these tapes at 24 fps in order to sync the audio from the tape with my 16mm film scans that are 24fps. Does anyone have any suggestions?


Capture as 29.97 then do inverse telecine in some software (AE, ffmpeg etc). Bring to NLE, assume as 24p and add your original audio. If tapes were done from the same masters as your audio and there was no editing after pulldown was added all should be in perfect sync.
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Max Winik

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Re: Capturing Beta Tapes

PostWed Jun 14, 2017 3:09 pm

So I added a Teranex Express to the mix. Converted the signal to capture at 24FPS in Media Express. When I go to sync with my 24 FPS film scans, the audio is still falling out of sync by about 15 frames for every 10 minutes. Using Davinci Resolve 12.5. My timeline is also set at 24fps. Does anyone have any other suggestions?
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JPOwens

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Re: Capturing Beta Tapes

PostFri Jun 16, 2017 2:27 pm

Max Winik wrote:So I added a Teranex Express to the mix. Converted the signal to capture at 24FPS in Media Express. When I go to sync with my 24 FPS film scans, the audio is still falling out of sync by about 15 frames for every 10 minutes. Using Davinci Resolve 12.5. My timeline is also set at 24fps. Does anyone have any other suggestions?


I think this is not the way to do it.

If you are doing a real-time capture/conversion, you will be digitizing at 29.97/23.98 (really 23.9754-etc). This is not 24.0000.

15 frames per 10 minutes seems to underscore the causative factor. Simplest solution might be to reassign the film scan dpx sequences to 23.98 and abandon the idea of 24.000. When the audio goes out of sync, does it lead or lag? My bet is that the audio is still running at equivalent to 29.97 (slow and eventually lags -- gets later and later.) This is also similar to drop-frame clock time mismatch. The error factor to watch for is 1001/1000.

This is a problem from the beginning of double system telecine transfer. Cinematographers used to always shoot at 24, with a Nagra recorder set at 30 fps. Transferring film from a Rank/Spirit slowed the frame rate to 23.98... 3/2 cadenced to match NTSC 29.97. The Nagra 1/4" tapes also had to be slowed to match the mechanical gate-sequence of the film scanner. If you are doing a real-time Teranex conversion, it is still operating in real time and you are not getting a 29.97--> 24.000 speed-up, you are getting a frame-blend interpolation.

jPo, CSI
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Andrew Kolakowski

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Re: Capturing Beta Tapes

PostFri Jun 16, 2017 4:27 pm

Solution is to capture as is and do rest in software (as I described). Real 24p is difficult with old SDI legacy equipment. With software you can do what you want in 10 different ways.
It's a bit waste of money adding fairly expensive hardware to deal with such a task.

If you want i can help you (but for a small fee) to go from 29.97 capture to 24p ProRes etc.
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Marc Wielage

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Re: Capturing Beta Tapes

PostSun Jul 02, 2017 11:01 am

Max Winik wrote:Using my UltraStudio 4K, I am trying to capture Beta tapes. I am playing back the tapes on a Sony J-30SDI. The tapes playback at 29.97fps. With Media Express, I am able to capture at that frame rate but I want to capture these tapes at 24 fps in order to sync the audio from the tape with my 16mm film scans that are 24fps. Does anyone have any suggestions?

If you have film transfers at 24.00fps, but sound at 29.97, then what I would do is capture the videotapes at 29.97 (SD or HD), then strip out the sound as standalone WAV files. Create a 23.98fps Resolve session, bring in your 24.00fps film picture material, and it will automatically apply the necessary .1% pulldown to run the film at 23.976 without any visual impairment. Bring in the 29.97 WAV audio files and manually sync it up, and "in theory" the sync should hold just fine because the film on the Betacam tapes was also running at 23.976.

I have done this for a couple of featuring mastering projects and it's worked just fine. About 10 years ago, I had a high-profile award-winning film where the distributor had completely lost the master audio tracks, but they still had a 1" standard-def videotape with Dolby A stereo tracks of the mags from the 1980s (!!!). We brought that in, synced it up, and damned if it didn't hold sync very well. That went out all the way to Blu-ray and nobody noticed.

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