Welcome to Doom9's Forum, THE in-place to be for everyone interested in DVD conversion.

Before you start posting please read the forum rules. By posting to this forum you agree to abide by the rules.


Go Back   Doom9's Forum > Announcements and Chat > General Discussion

Thread Tools Search this Thread Display Modes
Old 8th December 2017, 08:36   #1  |  Link
Registered User
varekai's Avatar
Join Date: Jul 2006
Posts: 310
Ultra-HD downscale to 1080p?


Is there a way to encode/recode/compress an Ultra-HD to 1080p BD or to 1080p mkv without getting washed out colors?
Done a few tests and I always get very pale colors.
I'm shure there is an explantions to this but I can't figure it out.
Is it even possible to downscale to 1080p and get "normal" full BD colors?
varekai is offline   Reply With Quote
Old 8th December 2017, 09:46   #2  |  Link
Registered User
Join Date: Feb 2002
Location: San Jose, California
Posts: 2,713
You probably need to do a color space conversion to BT.709. Most UHD content is encoded as either BT.709 or BT.2020 and if it was BT.709 colors would look correct.

The reason colors look pale is because BT.2020 is a very wide color space, 50% red in BT.2020 is much redder than 50% red in BT.709. Without doing a conversion all the BT.2020 color values are simply displayed as if they were BT.709 color values.

Another option is to tag your encodes as BT.2020, for x264 and assuming an SDR source this might be:
--colorprim bt2020 --transfer bt2020-10 --colormatrix bt2020nc

I have no idea how to do a HDR -> SDR conversion.
madVR options explained
Asmodian is offline   Reply With Quote
Old 8th December 2017, 10:37   #3  |  Link
Sparktank's Avatar
Join Date: Mar 2011
Location: Planet Express, Inc.
Posts: 788
for HDR -> SDR you can use FFMPEG's internal tone-mapping.
You'll have test various parts to ensure that different scenes don't look too out of place (light vs dark vs natural light vs etc).

It also looks pale if it's HDR content, which will need to be converted to SDR (via FFMPEG).

You could encode to HEVC in 1080p and keep the HDR metadata to passthru and let MadVR convert to SDR (this limits to PC playback only).

There's a vapoursynth script somewhere here to convert HDR -> SDR. Not sure how well it works compared to FFMPEG conversions.

Those are the only automatic processes that are free and easily accessible.
Win10 (x64) | GPU Caps Viewer v1.32.0.0
Crucial M500 240GB SSD | Kingston SSDNow V300 (Marvell) 120GB | NVIDIA GeForce GTX 750 Ti | R375.95 (Nov 18, 2016)
NTSC | DVD: R1 | BD: A
Sparktank is offline   Reply With Quote
Old 8th December 2017, 11:28   #4  |  Link
Registered User
varekai's Avatar
Join Date: Jul 2006
Posts: 310
Ahh... that's a lot more complicated than I was hoping for... :/
I'll just leave that project, 'cause it's a bit over my head.

Thanks for the the input though, appreciate that!

Best regards,
varekai is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT +1. The time now is 03:36.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2017, vBulletin Solutions Inc.