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Cheap HDR to SDR hardware conversion?
#1
I need an unique solution. I have a video chain in my “home theater” that is either uhd hdr or up-converted uhd sdr video. One part of the chain goes to a uhd panel capable of handling hdr and sdr.

The second chain goes to my legacy devices which are 1080p or 1080i. Converting 2160p to 1080p or 1080i is simple and effective enough with those cheap converters found on amazon. Problem is I can’t find a cheap solution for hdr to sdr conversion.

(Yes I know I can change the output in my hdr devices to sdr but I want to try to keep the chain in its native format if possible)

The radiance devices can tonemap well but those are expensive. I think some of the hdfuries might work but am unsure. I remember a set top box or two that you could load a lut into that you could, in theory, do a hdr to sdr lut for but can’t find them online anymore.

So shot in the dark does anyone know a cheap hardware solution for hdr to sdr conversion?
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#2
(2020-10-14, 02:45 PM)PDB Wrote: Converting 2160p to 1080p or 1080i is simple and effective enough with those cheap converters found on amazon.

While this is not your crucial concern and so neither I am sure if your approach intends to achieve decent quality or just "some" output at the end, besides the HDR to SDR tone mapping issue, I wanna make a note about the downscaling just in case:

I'd be surprised if those cheap devices do it properly in terms of not indirectly introducing at least aliasing due to just omitting samples. Don't you have any artefacts with those devices? If not, then they are post filtering properly against all odds or the UHD sources don't contain much higher frequencies (detail) than the HD counterpart to begin with.
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#3
Well downscaling is a hell of a lot easier then upscaling so I would expect some competency with even the lowliest of devices but my video chain seems just fine. No odd artifacts that I can see.

In this particular case, I'm running down to 1080i for a CRT so any aliasing from throwing out lines doesn't register easily anyway. Its only the HDR to SDR issue that's my holdup from watching 4k content on it. Basically trying to have one video chain.
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#4
Since so far I haven't even seen any "out of the box" tone mapping feature such as any built into ffmpeg or similar and considering the complex setting availability on a software renderer like MadVR, I doubt that any cheap device will give decent results as according to its developer and the discussions around that process suggest that it is a rather complex issue which I tended to underestimate myself before.

Also, in order to prevent banding, one wants proper dither during output to any lower video bit depth compared to the original (which some consider being something bad which essentially analog to the audio domain isn't but rather a crucial necessity).

However, maybe exactly that (MadVR*) might serve you by using a hopefully not so expensive PC and let it do all the work. Of course, at least from my experience so far that opens up a different set of worries like playback without micro stutters (as the output rate of graphic cards rarely really matches the video content), lack of comfort, etc.

* as it offers geeky settings like nits, color space, dithering
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#5
I still can't get over how poorly implemented HDR has been, even in HDR displays nevermind SDR conversion
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#6
Agreed and I think the mastering is just as bad as the end implementation.

I don't mind that there are all these standards. Most TVs will just incorporate them eventually (looking at you Samsung). My big problem is the mastering is all over the place with some movies being mastered at SDR levels still, 200, 1000, 2000, 4000 and even 10k. And that is with the same studio.
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#7
(2020-12-01, 12:07 AM)PDB Wrote: Agreed and I think the mastering is just as bad as the end implementation.

I don't mind that there are all these standards. Most TVs will just incorporate them eventually (looking at you Samsung). My big problem is the mastering is all over the place with some movies being mastered at SDR levels still, 200, 1000, 2000, 4000 and even 10k. And that is with the same studio.

This - and the fact I don't think the resolution bump to 4K justifies the massive price tag of upgrading my projector - is the main reason I haven't taken the leap to 4K yet. It seems like the wild West out there.

To some extent reminds me of Blu-ray in like 2008 or so when everybody was basically just releasing stuff from DVD masters with the same compressed Dolby Digital sound and calling it a day (and half of them were 1080i and/or straight up DVD upscales) but then a few years later we started getting new transfers that were actually decent (partly thanks to AVC, but definitely not exclusively). I'm kind of hoping that the dust settles as it usually tends to eventually and one day I'll feel like it's actually worth the jump.

More likely, what'll happen is they'll just continue this gradual trend of only including certain extras / audio in the 4K/UHD releases (including keeping the 1080p versions of the updated transfers exclusive to the 4K box) and I'll basically be forced to buy 4K discs more and more often even though I'm not even capable of displaying them properly. And I'll whinge about it on the internet more than I already do. I bought the HELLBOY 4K a while back just because it appears to be the only way to get the theatrical cut in 1080p, but the colour grading seemed completely screwed (massively skewed toward violet/purple for whatever damn reason, which could be theatrically accurate for all I know but I highly doubt it). I'm guessing they just graded it for HDR, made a total mess of the HDR->SDR mapping, and didn't check/notice/care. Similar deal with other 1080p bundled discs with 4K releases, specifically thinking of THE SHINING here. I need to try check BRAM STOKER'S DRACULA as well, no idea if the 1080p disc included with its 4K has a similar issue or not but there's no decent UK Blu-ray so...
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