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Koying · 2017-10-11, 08:21

Mmm... That derailed into android bashing quickly Wink

Kodi has no provision for color space translation, which HDR to whatever would be. Kodi does not even read the HDR metadata...

Good to know that the aml socs support it, somehow

wesk05 · 2017-10-11, 08:51

It is true that at present Amlogic does have tone & gamut mapping and it sort of works. I said "sort of" because these are Amlogic's proprietary implementation. There are no in force standards for dynamic range or color space conversions (BT.2020 to BT.709). They are still being finalized by WP 6C (ITU).
As for the Shield, Android Oreo has native gamut & tone mapping APIs. So, it is just a matter of time before Shield gets it.

wrxtasy · (This post was last modified: 2017-10-11, 09:17 by wrxtasy.)

(2017-10-11, 08:21)Koying Wrote: Mmm... That derailed into android bashing quickly

You conveniently forgot Apple got a decent whack as well. Wink

No idea why outlining Android deficiencies and providing decent working alternatives is labelled as Android bashing.
Maybe Android users just like continually fiddling with settings and implementing workarounds and still coming up empty handed Wink

Please detail a Android HDR > SDR working setup for Android users.

Koying · 2017-10-11, 10:15

(2017-10-11, 09:13)wrxtasy Wrote: Please detail a Android HDR > SDR working setup for Android users.

We know and (somewhat) respect your devotion to LibreElec, but this is still the Android forum.

A reply like "That doesn't exist for Android. There is some limited support in LE for amlogic" would suffice.
It's not like it is supported on all LE platforms, is it?

Honestly, HDR->SDR support is not anything that had even crossed my mind before I saw some (or the same?) people asking for it.

Why the heck would you rip (or download) in HDR if you don't have the hardware to play it?

Earwig · 2017-10-11, 13:02

To answer your question Koying, as to why get the releases now ?

Simply put, OLED screens are currently not at a point where I feel the need to spend £3-4k on one. There are still a few issues that I would like to see sorted before I spend that sort of cash. So in the meantime I bought the best LED 4K TV I could. 3-4 Months after I bought it.... HDR arrives.....

Now since I plan on buying an OLED, maybe in the next year or so, when issues have hopefully been sorted, I don't want to replace my TV now for an HDR model. That just seems silly.

Playing 4k HDR content with the proper HDR to SDR conversion still results in a far FAR better picture. This can be proved simply using MadVR and a PC plugged into the TV. The color is still far more vibrant and has far more depth that any regular BluRay.

So therefore, rather than replace the TV at this point, the best solution in order to play the best quality right now is to replace the media player/software.

And since I love Kodi/SPMC i really want to keep using it. I am on other forums and it's actually a more popular request/need/want in a player/software than you might think. Most people have simply opted to use a PC and MadVR though. But most would love to have another solution.

**wsnipex** · 2017-10-11, 16:05

(2017-10-11, 13:02)Earwig Wrote: Playing 4k HDR content with the proper HDR to SDR conversion still results in a far FAR better picture. This can be proved simply using MadVR and a PC plugged into the TV. The color is still far more vibrant and has far more depth that any regular BluRay.

Scientifically, this is like saying an $1000 HDMI cable has better picture then a $10 one.

Earwig · 2017-10-11, 16:47

Err.... No it's not.

A cable simply passes info from one place to the next. A piece of software that takes the HDR information and converts the colors into something a non HDR display can handle is entirely different. From what I understand, most TV's can display a much wider color gamut than is actually available on a regular BluRay disc, this tonemapping, or converting of the HDR meta simply uses a bit more of that ability to display the color.

Whilst it's not displaying HDR, you still get a deeper picture, more detail in dark areas etc. You should really check it out for yourself. You'd be quite suprised I would imagine ;-)

**wsnipex** · (This post was last modified: 2017-10-11, 17:12 by wsnipex.)

kodi uses RGB internally, so it will not show a wider color gamut than that.

edit: granted, blacker then black and wider then white is possible with this, which is generally not available on standard bluray

wesk05 · 2017-10-11, 17:54

(2017-10-11, 17:10)wsnipex Wrote: kodi uses RGB internally, so it will not show a wider color gamut than that.

I don't understand your logic. RGB, YCbCr, ICtCp all can represent any gamut.

**deltop** · 2017-10-12, 14:05

(2017-10-11, 10:15)Koying Wrote: Why the heck would you rip (or download) in HDR if you don't have the hardware to play it?

It's something that took me by surprise today.

I've got a 4k/HDR display in my living room but I retired the older tv to the bedroom. Plus the kids rooms don't have HDR capable displays.

Kinda expected that the Shield would support HDR to SD. I've no plans to replace the bedroom setup and hoped to just keep the (currently limited amount) of HDR files on my server rather than doubling up.

No biggie right now however and hopefully support will come via a fw update from Nvidia.

Koying · 2017-10-13, 08:34

@wesk05 I found a rec2020 to rec709 conversion matrix

Would this conversion be equivalent to HDR to SDR (quite academic, as we will not be able to adjust surface, anyway)?

Earwig · 2017-10-13, 23:17

Oh, this is now beginning to get kinda hopeful !

I have noticed more and more threads on more and more forums I visit. One actually popped up on the nVidia forums the other day also.

wesk05 · (This post was last modified: 2017-10-14, 19:56 by wesk05.)

(2017-10-13, 08:34)Koying Wrote: @wesk05 I found a rec2020 to rec709 conversion matrix

Would this conversion be equivalent to HDR to SDR (quite academic, as we will not be able to adjust surface, anyway)?

Not quite. It is only part of the conversion. You will also have to convert PQ OETF to BT.1886 OETF (SDR gamma). Have you looked at Amlogic's code? https://github.com/LibreELEC/linux-amlog...cm/amcsc.c
Amlogic refers it to as contrast adjustment. As I mentioned before, there are no published standards for doing this. You can do whatever you think is "right".

BTW, does Kodi decode to linear RGB?

Koying · 2017-10-15, 11:35

(2017-10-14, 19:55)wesk05 Wrote: BTW, does Kodi decode to linear RGB?

Not sure what you mean by "linear" RGB.
We don't do gamut conversion, if that's what you mean, at least in GLES.
I see there is some colorspace support in pure GL, but I have no clue.

Thanks for the code pointer.

iMak · 2017-10-15, 16:18

Now let the experts rule the world. Keep up the good work guys.