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S-VHS scan has many sudden frame rate drops


Jared Hall
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Is this an issue with the place that scanned this footage or is tape known for this? it may be a bit tricky to tell from the video but throughout all of my clips theres many moments where they experience little frame rate drops which makes it appear very stuttery and it won’t work for what i need the footage for. Should i just ask them to rescan it or is my tape the issue? Here’s the link: https://youtube.com/shorts/JQs0QoVryfI?feature=share

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Let me get this straight:  it is a S-VHS tape that was digitized to... what?  What was the file format you received?

No scanning was involved;  only a standards conversion.  Your S-VHS tape was recorded at an INTERLACED 29.97 fps, so if you had it converted to a 24 or 30 fps file, there has to be some frame duplication/elimination and consolidation to make it work UNLESS you throw it in DaVinci Resolve and use Optical Flow to re-time the footage.

Here's an explanation of frame rates from silent film to NTSC that should help understand the problem.

 

Edited by Frank Wylie
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2 hours ago, Frank Wylie said:

Let me get this straight:  it is a S-VHS tape that was digitized to... what?  What was the file format you received?

No scanning was involved;  only a standards conversion.  Your S-VHS tape was recorded at an INTERLACED 29.97 fps, so if you had it converted to a 24 or 30 fps file, there has to be some frame duplication/elimination and consolidation to make it work UNLESS you throw it in DaVinci Resolve and use Optical Flow to re-time the footage.

Here's an explanation of frame rates from silent film to NTSC that should help understand the problem.

 

Oh wow, thank you for the response. I got it as a mp4 file from the place that converted it. The frame drops don’t get worse until about half way in to the end of the 90 minute video. I’ll watch that video once i’m off work but i started editing the footage together and it actually doesn’t look to bad fortunately. It’s just odd to me because I had this same place convert my hi8 tape and had none of these issues. But I wasn’t sure how the tape conversion process worked I assumed they recorded it from the vhs playback and the capture card or whatever they used was at fault

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Ugh. MP4.  Not a good file format at all for editing;  barely good for viewing.  If that's all you can get, transcode it to DNxHR SQ  or Apple Pro Res before you try to edit.  The files will be larger but you won't encounter all the weird issues with on-the-fly decompression your computer has to do during the edit.

Well, it doesn't mean that the transfer/conversion is OK; just that you should expect a few artifacts. 

I would show it to them and see if you can get a better transfer. 

It could be that you have frame cadence, field-order and interlace issues IF they used a hardware encoder and didn't set it up right.

You wouldn't believe just how complex a simple transfer can become and all the things that go wrong!

Here's an FAQ from the source listed above on frame cadence:

https://www.insync.tv/information-learning/faqs/

The second link is from Chris and Trish Meyer; the stone cold gurus of Adobe After Effects.  It might deal with After effects settings, but the article is a great tutorial on problems that might occur with a bad field order.

Good luck.

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