Log in

View Full Version : Converting from UHD HDR to HD SDR with very grainy film...


Lathe
9th November 2024, 01:56
Basically that...

I'm using the excellent Clever FFMpeg as I usually do for this and I'm converting the recent 4k print of 'THE THIRD MAN', which has always been a SUPER grainy film.

Well, with the usual settings HDR-SDR using Haber or Mobius, don't know which would be best in this case, and a desaturation of '1' what it renders does something really weird with the grain, almost giving it a luminescent glow... :)

I don't know if I can tweak the setting much, or if I should try 'Tune Grain' which I never use, but any suggestions on how I can set this to look a LOT better? Or, perhaps if I should use Handbrake which doesn't have such a varied, 'Trick' HDR-SDR setting, but I CAN add CMD line options for the x264.

Any help would be great, thanks!

***EDIT

Oh, and I CAN add Avisynth script to Clever FFMpeg, but it needs to be very simple, perhaps a way to tone down the grain a little or whatever else may help, but I've had trouble getting anything too complicated in AVS to run. Thanks!

***EDIT 2

Okay, I changed the settings of Clever FFMpeg to using Mobius and a desaturation of 2 AND I did set it for Tune-Grain. NOW, it does indeed look a hell of a lot better! Still a pretty damn grainy film, but...

So, I can live with this, but if anyone has any suggestions, that still would be awesome! Trust me, I am not a total grain Hater, but also I'm not opposed to toning it down a bit if clarity and sharpness aren't compromised.

Emulgator
9th November 2024, 08:28
SMDegrain(tr=6, thSAD=400, RefineMotion=true, contrasharp=false, interlaced=false, plane=4, prefilter=8, chroma=true, Show=false) #5: DFTTest, 6: KNLMeansCL, 7: DGDenoise, 8: BM3D
This is just a snippet I used for a certain source, please match to your source.
tr=6 might be overkill, prefilter=8 is nice, but slow.

SeeMoreDigital
9th November 2024, 14:08
Basically that...

I'm using the excellent Clever FFMpeg as I usually do for this and I'm converting the recent 4k print of 'THE THIRD MAN', which has always been a SUPER grainy film.

Seems like a lot of work when you can simply play/back-up the 2K blu-ray disc that comes packaged with this release!

benwaggoner
11th November 2024, 02:30
Seems like a lot of work when you can simply play/back-up the 2K blu-ray disc that comes packaged with this release!
Yeah. Converting HDR to SDR in general feels like a sin. Getting some degree of HDR playback is pretty easy on PC these days. And a "better than SDR" HDR display is quite affordable.

GeoffreyA
11th November 2024, 06:23
Lathe, try setting the desaturation to zero. FFmpeg's tonemap filter has got a problem when the desaturation setting is non-zero, creating blown-out patches or even discolouration. Also, give Habel or Reinhard a try: they are usually better than Mobius, which tends to leave the highlights too strong.

Z2697
11th November 2024, 10:22
You can try libplacebo for tonemapping in AVS
https://github.com/Asd-g/avslibplacebo
(There's libplacebo filter in FFmpeg as well, but it's not very stable, not a very good experience to use.)

But better thing to do would be using the SDR disc or preserving HDR like they said.

Tune grain is not really great to use in my opinion. Increase bitrate like normal will be just fine.