VHS Ai conversion advice please - examples attached

Topaz Video AI General
1

Hi All,
Testing converting a VHS recording with Topaz AI, any advice on how to reduce the scrambled/wavy lines? I’m open to purchasing another product as well, some suggested neat video reduce noise in other posts.

Thanks for any advice and if you know the technical term for the wavy lines please feel free to list.

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2

The wavy lines are interlacing. They’re going to be tough and you’ll need to do a lot of tinkering with settings, but try this to start:

  1. Set output resolution the same as input
  2. Turn on an enhancement and set Video type to Interlaced
  3. There are three options for Field order. Try them all to see which works best
  4. For interlacing as bad as yours, I seem to get the best results from the Iris model, and you will definitely need to use Relative to Auto or Manual and play with the sliders. But try the other models, too. Maybe you’ll get lucky.

And be prepared to have to live with imperfect results. Interlacing is like that sometimes.

3

Thanks so much gene-8240 for your advice, appreciate it. Will reply with results as may help others with similar requests for old VHS videos.

4

Probably not. I’ve never had the settings for one of those old vids work well on another one. That’s why so much of my suggestions consists of “try them all.”

5

That looks like it needs time-based correction (TBC) during capture.

If you have access to the original tapes and can re-digitize, then do so. There’s lots of advice out there from archivists that start with:

  1. Get a TBC. That should stop that horizontal scan wobble. You can get TBCs on ebay, or search the Goodwill stores for a prosumer VCR with a built-in TBC.
  2. Clean your VCR heads. Many folks open up their VCR and clean and even apply a tiny drop of light machine oil to the moving parts.
  3. Fast Forward the tapes through completely from start to finish a couple of times to clear off the flaked oxides. (you may need to clean your VCR heads again).
  4. If you have S-Video connections, use them in preference.
  5. Reseat analog A/V connectors to get a good connection on what may be tarnished A/V connectors.

That is going to go the furthest to reducing the instability on the horizontal scan. Those wobbles are not interlacing, they are a result of timing issues on the horizontal scan. Deinterlacing would come later.

For the brave, the current coolest project out there is GitHub - oyvindln/vhs-decode: Software defined VHS decoder - Fork (maybe temporary) of the ld-decode Laserdisc rf decoder, where you tap in behind the VHS head. It is a really nerdy hardware hack, but the folks on VHS-Decode and LD-Decode have started doing some amazing stuff stabilizing VHS through software techniques. It involves some hardware and a few steps, but it really is amazing what they are doing. This avoids the need for a TBC.

If you can’t be bothered with a TBC, send 'em off to be professionally digitized by a reputable firm.

Some folks who have stable clocks even do capture several passes (Multipass!) and overlay one pass over another at half intensity using a NLE tool.

Anyway, once you have a stable capture from either TBC or VHS-Decode, you are likely to need to:

  1. dedot filter (to remove dotcrawl + rainbow)
  2. deinterlace filter, which you can do with QTGMC (hard!), Topaz (easy) or another tool like FFmpeg
  3. denoise filter in the temporal chroma plane using something like hqdn3d or Neat Video. VHS captures benefit from a heavier temporal chroma denoise, and a lighter temporal luma denoise. Avoid spacial denoisers unless you really, really know that you need one - overuse can lead to blur.

With a source like that, there’s a whole bunch of pre-work that would need to be done before TVAI. Once you have a stable source (from either TBC or VHS-Decode), you are probably only going to be able to get away with a 1x enhance, maybe 2x at a stretch.

There is lots of better advice out there of the forums than mine, but I hope this gives you some pointers for background research.

Search terms:

  • time based correction (TBC)
  • cleaning VHS
  • VHS-Decode
  • temporal chroma noise (esp Neat Video)
  • dotcrawl & rainbows (dedot)
3 Likes
6

Thanks so much a-cli-user for providing your suggestion and this information. Didn’t know it was horizontal scan wobble. I unfortunately don’t have access to the VHS tapes. Will research online for any advice if one doesn’t have original tape. Appreciate your time.

7

I second on the TBC.
Great and important advice when it comes to VHS tapes.