Huge output file for black/white movie

[dvdcollector]

Description of problem or question:

I ripped an old black/white movie from a Bluray disc, converted down to 720p. Audio was set to convert to AAC 192kbps.
The movie is 1h 27min long, the output file is almost 6 GB, which seems excessive at that resolution, like ~ factor 4...6x excessive.
(The source folder is 20GB)

I searched a bit around and found the tip to set a filter for denosing, to NLMeans (I left it on Ultralight, and Tune to Grain, as the tooltip text said this might preserve more detail)
This didn't help at all.

Other settings pretty much default (see below).

It makes intuitive sense to me that reducing "grain" should yield better compression, like any redution in image changes would.
I also don't want to get a blurry image.
Should I just try heavier settings than "Ultralight",
or do something completely different?

Steps to reproduce the problem (If Applicable):

• "Open Source", drag 20GB source file onto the GUI
• load "Fast 720p30" preset
• change to mkv output format
• set filter: Denoise NLMeans/Ultralight/Grain (but did not tick "grayscale", as not sure how perfectly gray original is)
• FPS -> "same as source" (I don't see the sense in messing with the source rate)
• Video codec on default: x264, Quality: Constant 21 RF
• Audio set to AAC 192kbps

HandBrake version (e.g., 1.0.0):

1.3.0

[rollin_eng]

Could you please post your HB logs, instructions can be found here:

https://handbrake.fr/docs/en/latest/hel ... y-log.html

[dvdcollector]

https://pastebin.com/TQSJL5WN

[mduell]

To get the size down, you're going to have to reduce the grain rather than try to preserve it.

Set nlmeans to light or medium and don't use a tune. Or try hq3dn denoise rather than nlmeans.

FWIW I'd also leave it at 1080p and just increase the RF target to the mid-high 20s. It's not worth dropping resolution (unless it's a playback environment constraint) until the RF is in the low 30s.

If the movie is truly black and white, enable greyscale encoding so it just does the luma channel and skips the chroma.

1GB is a pretty aggressive target for a 1h30 movie, especially one that has any complexity in encoding like motion or fine details (grain is both!).

A slower preset wouldn't hurt to keep the quality decent as you get the size down.

[dvdcollector]

Ok with medium denoise, grayscale and 720p I got it to 1,8 GB which seems reasonable and it looks ok (it would get ~ 1 GB more with 1080p and otherwise similar settings, I ditched that one)

Thanks!

[dvdcollector]

Now adding a thanks for the tip for using NLMeans, with which I have considerably shrunk a lot of old visually noisy movies, B/W and color, and it sometimes even looks a bit clearer instead of muddier, as I would expect from low pass filtering.

But a question, too:
Is there a good way to reduce very coarse noise / reduce the file size?
I now encountered a gray scale movie from the late 40s or so, they scanned it in 1080p. And, I have to say... it really does look like there is some benefit to that resolution, one does see more detail "between the noise", but the grain is rather large, and NLMeans on heaviest setting does not achieve a lot of noise or size reduction.

[mduell]

Try the hqdn3d denoise filter instead, it's much more of a blunt tool than nmleans.