UHD BD to BD?

[Doctor M]

I've noticed an unpleasant trend lately. Studios are releasing new 4k transfers with HDR and wider color gamut, etc. and then simultaneously pooping out either a repackaged old transfer or intentionally degraded version of the new transfer as 1080p discs at the same time.

Sometimes the colors are worse for no legitimate reason, frequently they are scrubbing grain like it's 2008.

What is clear from screenshot comparisons is that you can maintain a lot of the improvements of the 4k releases without the actual UHD enhancements.

Anyway, being a staunch anti-4k/HDR person, I've been wondering what would be involved in creating new 1080p discs using the UHD BDs as a master.

I honestly haven't the slightest idea where to start or what software is capable of it. I'm aware the HDR needs to be tone mapped(?) to SDR... and that's about it.

Case in point, The Mummy Trilogy got a recent 4k release that looks great. Except most people agree the film doesn't have 4k worth of detail. The similarly packaged BDs that came out this year are the same 10 year old transfers they keep repackaging.

What might a UHD to BD conversion look like? Check out these screenshots: http://forum.blu-ray.com/showpost.php?s=...count=1579

[spoRv]

Just checked The Mummy screenshots, and the HDR-to-SDR conversion seems done right!

If I am not mistaken (and it is probably not the case), HDR material mastered at 1000nits (and viewed on a 1000+nits display) are not dinamically mapped, but they are just plain 10bit, 0-1023 reduced to 64-940 range

if a TV can deliver 100% of DCI-P3 and 1,000 nits of peak brightness, then for content graded at 1,000 nits the TV will take a one-to-one approach and simply show the content as it was created.

(https://www.avforums.com/article/what-is...ping.13883)

So, in those cases there should be a (right) univocal way to convert HDR to SDR.

[captainsolo]

I'm interested in this idea since I'm not yet 4K prepped and use much older but still good equipment. It'd be nice if 4K players could simply downscale properly like a BD player can do lesser resolutions.

[Beber]

The Zappiti 4K HDR player supposedly has a new Beta 3.10 firmware that includes a better HDR to SDR conversion: http://www.zappiti.com/restore-hdr-3-10.html



My player, however, still not has offered me to update. Whenever I go to the update page, it doesn't detect a new firmware to download. Maybe because it's still a Beta version that needs to fix some glitches. I'm eager to see it ,'cause the 3.09 conversion does look bland like on the picture above and the 3.10 comparison promises to be more pleasing.

[deleted user]

I did an UHD to normal conversion, kinda, specifically for the first movie of the Mummy series. I just created a LUT using DrDre's ColorMatch tool (using old BD als reference) and applied it with ffmpeg. Turned out pretty well imo.

[X5gb]

Marban over at the German BS forum made excellent 1080p hdr to sdr conversion's of the Mummy Trilogy (unfortunately, he used the European version without the original burnt in subs). I sent him a pm asking if he could explain his procedure but never got a reply. Would also love to know how so I can convert both the Grease UHD (one I did still has the hdr and have to use madvr on the fly to convert while watching but makes my graphic card work overtime) and Die Hard (at a decent bitrate unlike the low bitrate one which is floating around).

[Chewtobacca]

I've noticed an unpleasant trend lately.  Studios are releasing new 4k transfers with HDR and wider color gamut, etc. and then simultaneously pooping out either a repackaged old transfer or intentionally degraded version of the new transfer as 1080p discs at the same time.

You're not alone in thinking this. I'd love to know a surefire way to convert UHD discs to standard BDs.

[deleted user]

Marban over at the German BS forum made excellent 1080p hdr to sdr conversion's of the Mummy Trilogy (unfortunately, he used the European version without the original burnt in subs). I sent him a pm asking if he could explain his procedure but never got a reply. Would also love to know how so I can convert both the Grease UHD (one I did still has the hdr and have to use madvr on the fly to convert while watching but makes my graphic card work overtime) and Die Hard (at a decent bitrate unlike the low bitrate one which is floating around).

Pardon, but what is "German BS forum"? Google doesn't help.

P.S. The version I made of the first one does have the subs.

[X5gb]

TomArrow, you have pm.

Just read somewhere that freeware ripbot264 does a pretty good job at tone mapping hdr to sdr as well as staxrip.

[Doctor M]

I guess I'm not alone in wanting to know how to do this.
In fact, most of the movies people have named above are EXACTLY the reason why I'd like to learn how to do this.

I did hear a little bit of talk over on Doom9 that a future version on BD Rebuilder MIGHT include this ability. I don't know how serious the author was about the idea.

Although it does sound like at the moment all we have is movie-only conversions with pre-defined encoder settings.