this post was submitted on 10 Sep 2024
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datahoarder

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I have a bunch of old VHS tapes that I want to digitize. I have never digitized VHS tapes before. I picked up a generic HDMI capture card, and a generic composite to HDMI converter. Using both of those, I was planning on hooking a VCR up to a computer running OBS. Overall, I'm rather ignorant of the process. The main questions that I currently have are as follows:

  • What are the best practices for reducing the risk of damaging the tapes?
  • Are there any good steps to take to maximize video quality?
  • Is a TBC required (can it be done in software after digitization)?
  • Should I clean the VCR after every tape?
  • Should I clean every tape before digitization?
  • Should I have a separate VCR for the specific purpose of cleaning tapes?

Please let me know if you have any extra advice or recommendations at all beyond what I have mentioned. Any information at all is a big help.

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[โ€“] ChaoticNeutralCzech 2 points 2 months ago

With the interlace filter, make sure you get the field order right. I used not to be so familiar with ffmpeg and I ended up using some GUI program I can't remember back in the day. See if the driver has an option for no deinterlacing because that happens at driver level.

There is no difference between 1โ…“:1 and 4:3, they're just different representations of the same thing. Rounding the ratio to 1.33 produces a negligible difference but I would stick with 4:3 for a simpler pixel aspect ratio of 9:8 (1.125} as opposed to 150:133 (1.12782), assuming the capture is 720x480i60.

As for the zoom, TVs will have some overscan because different equipment caused various borders but the capture card should capture all 480 lines. You can check that the output is not vertically scaled by taking a snapshot in a high-movement scene (beware that most image formats are limited to square pixels so better force a PAR of 1:1 for this purpose) and observing if the interlacing indeed causes 1:1 combing as expected. Checking for horizontal crop can be done with another video source (camera, DVD player, STB, game console) generating a test pattern or at least a known image. However, if the vertical scale is correct and the content aspect ratio looks subjectively fine at 4:3 SAR, the crop is most likely OK.