datahoarder

I'm trying to digitize some VHS tapes (presumably recorded as NTSC), but I have some questions that I've yet to find answers for. My current process/setup is as follows:

• VHS tapes are played in a PV-D4745S-K VCR
• The VCR's composite output is captured using a generic EasyCap capture card.
• The captured output is fed into OBS Studio with the following settings:
  • A source with it's device set to the capture card, the video format is set to YUYV 4:2:2, the resolution is set to 720x480, the frame rate is currently set to Leave Unchanged (more on this later).
  • Under Settings>Video I have set Common FPS Values with 29.97.
  • I also have set my encoding options under Settings>Output, as well as audio settings under Settings>Audio, but the details of that aren't relevant in this context.
  • I also have deinterlacing disabled by right clicking on the scene and selecting Deinterlacing>Disable.

With this, I seem to be able to capture VHS tapes with decent quality, but I have some nagging questions:

1. How do I verify if OBS has indeed captured interlaced? I'm trying to capture both fields, but I'm unsure if that's actually happening, and I'm not sure how to go about verifying it.
2. Should I capture at 29.97 FPS or 59.94 FPS? My thinking is that, given that I'm capturing interlaced, I would think I would multiply the number of captured frames by 2 as, if I understand correctly, each captured frame contains 2 fields, and each would be captured sequentially, so if I want to capture at 29.97 FPS interlaced, I would need to capture at 59.94 FPS. I'm not sure if I'm right about that though.
3. I mentioned above that the framerate under the source properties is set to Leave Unchanged. The reason for why I chose that option is because the only other options that it offers for framerates are 30.00, 20.00, 10.00, and 5.00 — ie there is no option for 29.97, nor 59.94 — so I'm using Leave Unchanged in the hopes that it's autodetecting the proper frame rate, but that's mostly an assumption on my part. The closest to NTSC's 29.97 would be 30.00, but I'm not sure if this is an issue. And what's confusing me more is that I have 29.97 FPS set under Settings>Video with Common FPS Values and 29.97 set. If I set to source framerate to 30 with OBS at 29.97, will that lead to syncing issues? Is there a way to force the source to use 29.97 to match OBS? What's confusing me further about this is that if I list the formats for the capture device with

   v4l2-ctl --device=/dev/video2 --list-formats-ext
   

   I get the following output (I have truncated it to only list what's relevant, as the full output is long and contains unnecessary information):

   […]
   [0]: 'YUYV' (YUYV 4:2:2)
       size: Discrete 720x480
   […]
        Interval: Discrete 0.033s (30.000 fps)
        Interval: Discrete 0.050s (20.000 fps)
        Interval: Discrete 0.100s (10.000 fps)
        Interval: Discrete 0.200s (5.000 fps)
   […]
   

   There is no option for 29.97 FPS, and, as can be seen by the output, it matches what OBS sees. Is this an issue? It seems, to me, that the capture card isn't capable of proper NTSC framerates, and can only capture at 30 FPS as the closest value.