What can be done about this kind of noise in dark areas?

[brassplyer]

This is from a DV capture via Firewire from VHS. I've exaggerated the issue with contrast filters for the purpose of demonstration - what I'm referring to is the lack of graduation in brightness in the darkest areas. This is after treatment with Neat Video and deinterlacing with QTGMC via Avisynth and conversion to Huffyuv, however it's visible in the original interlaced DV video. Neat Video softens it but so far I haven't been able to eliminate it.

Is this just a limitation of the kind of video I'm working with or is there more that can be done?

Thanks

[poisondeathray]

Something like this is typically worsened with overdenoising (natural grain and noise in the clip tends to hide it - so you end up with posterization effects)

You would dither , add fine grain and noise , or adjust your denoising practices

If you post an unprocessed clip, someone might give you some suggestions . It will probably involve filtering shadow areas differently (e.g. with a mask through sections) , because well lit areas are likely not as strongly affected like this

[Mephesto]

Do your brightness/contrast adjustments BEFORE denoising. The noise profile you give it will post-process such noise accordingly so the current picture looks its best without it, not some supersaturated version that accentuates the banding artifacts that would otherwise be invisible on the picture you gave it. The alternative is more aggressive denoising that will unnecessarily destroy a lot more detail but surely won't be visible even with the brightness/contrast turned all the way up.

So do all your color adjustments first where the noise can become as aggravated as it wants to be, then with the new proper noise profile your adjusted video will look really good.

There's no way to get under the layer of film grain in a 2D video. The best denoisers don't "remove" the grain but "lock" it so it doesn't move anymore and thus the detail is isolated temporally.