Compressing (Handbrake) blu-ray MKVs once ripped with MakeMKV?

[NotMeOssifer]

I've done a number of blu ray discs. That many that they're scattered over 3 hard drives now, which I don't particularly want.

I'm sure you all know as you'll have all done the same but the rips are in and about the 20GB-40GB range. I don't think I have any blu ray over that or under that.

What I want to do is compress the MKV files so that:

1) I'm saving space (obviously)

...BUT...

2) where there is no obvious loss in image quality.

There obviously has to be some kind of loss as it's being compressed but I want to watch these movies back (TV: Panasonic LED TV TX-58DX750B) via Plex and not even know they've been compressed. I would like for say someone else to come in & think they're watching the blu-ray disc itself.

So no grainy images in other words.

So with that in mind, what kind of filesize are we talking about getting say a 30GB (middle of the park) file to? Not what can we get it to as in the smallest file possible, but what is a realistic file size while still retaining no obvious loss in image quality?

And if you care to talk about settings then don't let me stop you. The more help the better

[Woodstock]

You can adjust handbrake to compensate for how much quality you want. A video disk (DVD, BD, or UHD BD) is already compressed; it's compressed ENOUGH to fit the format.

I compress everything to RF 20 to 18 and get pretty good compression. I have no idea if it's "perfect", because I'm NOT watching anything to the level of "oh, an image defect!" when I'm watching TV. I could probable live with BDs compressed to 14 if I "needed space". But I'm only halfway through my 60TB RAID array, so I'm not desperate for space, yet. That's with around 30 thousand episodes of TV series and around 600 movies. Almost all of them are compressed between 18 and 20 with handbrake.

EVERYTHING goes through handbrake after ripping, except the couple of 3d titles I have. I rarely look at anything (beyond trying to determine what subtitles are in the mix) before handbrake runs against it.

[dcoke22]

I prefer to use the command line to compress rips. I've been using Don Melton's Video Transcoding Tools to that end. The files produced with those tools have no obvious flaws or loss in quality compared to the original rips. A 30GB rip will end up under 10GB and often under 8GB.

Those tools use the major open source projects, like Handbrake, to do the heavy lifting. They produce h.264 files in a .mkv container by default, which is highly compatible with lots of playback setups.

[wmcclain]

I use -q 18 on DVDs and -q 20 on Blu-rays.

DVDs compress by a factor of 2-3x, but Blu-rays have a much wider range, from "just about nothing" to 10x and more.

Grainy sources are hard to compress, but modern films with lots of CGI and grainless digital cameras compress like a dream.

You should pick a source you know well, say 1 chapter, and test it with various Handbrake levels and and presets. See what you can detect on your display.

[DataMeister]

I use -q 18 on DVDs and -q 20 on Blu-rays.

DVDs compress by a factor of 2-3x, but Blu-rays have a much wider range, from "just about nothing" to 10x and more.

I have not found a Blu-ray that doesn't compress at 3:1 or better. Which titles are you seeing that do that?

[wmcclain]

I use -q 18 on DVDs and -q 20 on Blu-rays.

DVDs compress by a factor of 2-3x, but Blu-rays have a much wider range, from "just about nothing" to 10x and more.

I have not found a Blu-ray that doesn't compress at 3:1 or better. Which titles are you seeing that do that?

Very grainy sources. Criterion's "12 Angry Men (1957)" was 1.33x. Mill Creek's "Age of Consent (1969)" was 1.57x.

Sometimes the cause is not grain but some other video processing I do not know how to characterize.

[ArArdin]

Preserving grain takes both CPU power/time and size, compared to "smoother" video. One likes it, others may hate it.
If you don't mind losing some grit, apply a grain/noise filter. Be very restrained with the settings though. Usually very weak to medium will do. Handbrake has a few onboard that you can try. Can save up quite some harddrive space.