Green stains, light trails in VHS digitized?

[ethanise]

Hi. I captured several VHS tapes using VDub with workflow equipment from Lord Smurf.

I've been attempting to catalog the most common problems that could use restoration from this forum and others. However, I noticed two problems in some of my tapes that didn't seem to be mentioned elsewhere.

1. Green stains from bright light
Very bright areas, often in contrast to a dark room, result in green stains or casts.
The first sample is from around '78-79. I believe this was shot on a camera with separate tape deck.
Second is from '86, and it's a camcorder. Same problem.
What would you call this, and what causes it?

2. Light trails
This footage was shot in a very dark lava tunnel in Hawaii, also in '86. Notice the trails from inside lighting.

[lordsmurf]

These are not green "stains".

#1 is the Kelvin temperature of light causing a white balance issues. This can be corrected, either entirely or partially, with varying color correction methods. Avisynth, VirtualDub Colormill, Premiere.

#2 is blooming, turned chroma bleed, and luma hotspots, also likely from Kelvin white balance. This is harder to correct, and often needs advanced After Effects matting. Or mere reduction with VirtualDub CCD, or another chrome NR filter.

This is what happens with consumer gear, under non-controlled lighting.

Light trails are the CCD/CMOS in the camera. Mix of concepts, including slow shutter. There's no way to fix that. Enjoy the light show.

None of this is unexpected from home movies. We have this in ours, especially the oldest VHS camcorder tapes (over the shoulder camera).

[ethanise]

Thanks, LS!

So, IIUC, the ideal would be to color correct in a way that separately treats the super-bright sometimes blooming areas from the rest of the frame (which would also need its own color correction)?

I'd like to color correct in Premiere Pro on my Mac, so would the correct workflow be the following?

1. Capture via VirtualDub => Huffyuv YUY2 (setting levels to reduce illegal values)
2. Filter using CCD or chroma NV via VirtualDub, if needed
3. Convert via Hybrid => ProRes 422 HQ
4. Edit and color correct in Premiere on Mac
5. Keep ProRes file as archival; Convert via Hybrid => H.264 for local Plex and streaming

I'm disregarding the option of using Perian on the Mac, since it hasn't been compatible since OS Mountain Lion (replaced 2013) at most.

Would I need to convert the color space before filtering or exporting?

[lordsmurf]

Do this instead:

- capture VirtualDub on Windows (be sure to YUY2 input/output, Video > Color Depth)
- CCD in VirtualDub2, output ProRes422 .mov (be sure to YUY2 input/output, Video > Decode Format)
- color correct in Premiere Mac
- QTGMC deinterlace + H264 encode Hybrid on Windows (reads ProRes422)

However, a Mac version of Hybrid exists, uses Vapoursynth for QTGMC. Try that first before falling back on Windows for Hybrid use.

Perian is great, allows direct access to Huffyuv captures, but isn't needed here.

These won't be an easy color correction, but it can be vastly improved. Just learn all the CC filters in Premiere, test a lot, save lots of undo levels.

[ethanise]

Thanks, LS.

I don't know why the homepage for Hybrid says they don't support Mac anymore, when they offer a download package dated 2020-10-11. They even mention that it should be supported on OS 10.15, which was the latest version until today. Sounds like they may have stopped development in 2018, and then picked up again this year.

In any case, I can't use the latest version until I upgrade from 10.12 (Sierra). I'll look into the older one, but they do indicate that there have been "a lot of fundamental internal changes" in the version from 9/2020.

Also, a question about capturing settings. Isn't the Video menu supposed to be set to "Direct Stream Copy"? If that's the case, then Color Depth is greyed out. The only place I seem to be able to change color space is under Video->Set Custom Format, and I believe the default for HuffyUV is already YUY2.

[lordsmurf]

You're not Direct Stream copying. You're reencoding to ProRes422. You must reencode, period, by using filters like CCD.

Capture settings have no relationship to editor settings, namely copy/encode modes.

Hybrid hasn't changed much in terms of the basics: QTGMC, encoding H.264. Go ahead and try whatever older version is still supported by your OS.

[ethanise]

My question was about the first step you listed: capturing to VirtualDub on Windows. In the parentheses, you wrote: "be sure to YUY2 input/output, Video > Color Depth".
However, that menu option only exists before entering capture mode.
In capture mode, the only options I see that affect the color space are Capture Pin (which doesn't give you other options beyond YUY2) and Set Custom Format.

[lordsmurf]

The Color Depth / Decode Mode is not done in capture mode.
In capture mode, the codecs directly control the color setting, if available.