Real-world support for full range and greater color depths [Archive]

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benwaggoner

9th October 2012, 17:31

I am doing some playing around with 0-255 luma range and 10-bit encoding.

I was wondering how good real-world player support is for those modes. I know that there are certaninly good software players for those. But how about GPU accelerated playback? Or ASIC-based playing in living room and handheld devices?

I imagine 0-255 is more broadly supported, since it's part of the original profiles. I know there's been plenty of talk about 10-bit support in ASICs, but I'm not sure if those are in the wild yet, or if the devices's media software will support correct playback of those if provided with files in Hi10P. Let alone Hi422P or Hi444PP.

So, can anyone offer any tips for what players and devices are or are not known to work? I'd love to be able to see what kind of quality differences I can get outside of computer monitors.

Blue_MiSfit

11th October 2012, 05:51

I'm not aware of a single consumer grade hardware player.

There are plenty of hardware players for the pro market, but even those are few and far between in my experience. AVC-Intra is about the only common implementation I'm aware of...

vivan

11th October 2012, 15:48

I could be wrong, but xvYCC looks like fullrange and AVCHD supports it (and there are a lot of players that support it)...

benwaggoner

11th October 2012, 17:38

I'm not aware of a single consumer grade hardware player.
You mean for the 10-bit and higher profiles?

I'd think that there should certainly players out there that can handle High Profile using a 0-255 luma range. Or is even that not broadly supported?

I could be wrong, but xvYCC looks like fullrange and AVCHD supports it (and there are a lot of players that support it)...
Link?

I'm sure that plenty of things that can play AVCHD out over HDMI can use xvYCC, but I don't believe the AVCHD bitstream itself can be anything beyond 8-bit 4:2:0. So it'd have to use post-decode upsampling in the player itself.

Blue_MiSfit

11th October 2012, 19:02

Right. I'm sure any hardware player could PLAY full range, but whether it would display it correctly is another story entirely :)

In any case, I have no experience in this matter whatsoever!

ajp_anton

13th October 2012, 13:05

Full range has no effect on the bitstream. The only difference is that with TV range, the "contrast" of the image is bad, and there's a flag that says whether this should be compensated for or not.
I can imagine some players just ignoring this flag and automatically compensating for it even if they shouldn't, so the blacks and whites will be crushed in the final displayed image, but it will be decoded correctly in any case.

benwaggoner

18th June 2013, 21:27

I could be wrong, but xvYCC looks like fullrange and AVCHD supports it (and there are a lot of players that support it)...
Coming back to this some months later.

Are you saying that xvYCC would require --range pc and not --range tv?

My understanding of xvYCC is that it wouldn't have luma our of the 16-235 range. But does it need --range pc in order to allow the broader chroma range for xvYCC?

It seems like we'll need the xvYCC flag for playback to not get black levels wrong in this case.

kabelbrand

19th June 2013, 10:42

http://www.sony.net/SonyInfo/technology/technology/theme/xvycc_01.html
With 8-bit quantization of luminance and color-difference signals, definition formula are set and the color gamut is expanded by using values between 1 and 15 and between 241 and 254 as picture signals. Definitions over 8 bits are also used to support precise gradation.

My understanding is that besides using luma and chroma values outside of the TV range you would still set the encoder to TV range for compatibilty with non-xvYCC devices.
This is assuming the encoder does not clip the input levels to TV and encodes the full range. I think x264 handles it this way as long as input and output range are the same.

SeeMoreDigital

19th June 2013, 16:57

Although there are some GPU's that support vxvYCC colour, they need to be connected to a display device that also supports vxvYCC... And currently these are only manufactured by Sony :eek:

kabelbrand

24th June 2013, 18:00

I had a quick look at the histogram of the "Mastered in 4K" Ghostbusters BD and levels seem to be within the regular video range!? This is not what I expected...

SeeMoreDigital

24th June 2013, 18:09

I had a quick look at the histogram of the "Mastered in 4K" Ghostbusters BD and levels seem to be within the regular video range!? This is not what I expected...Please list your playing and viewing equipment?

benwaggoner

24th June 2013, 23:22

I had a quick look at the histogram of the "Mastered in 4K" Ghostbusters BD and levels seem to be within the regular video range!? This is not what I expected...
Just because they had a workflow that could preserve xvYCC colors doesn't mean that the master actually had many. I've not seen that particular Ghostbusters discs, but most version I've seen are pretty washed out. The mid-80's weren't a golden age for film stock.

kabelbrand

25th June 2013, 10:39

Please list your playing and viewing equipment?

I used AviSynth with DGDecNV to load the elementary stream and added Histograms in Classic and Levels mode.

Just because they had a workflow that could preserve xvYCC colors doesn't mean that the master actually had many. I've not seen that particular Ghostbusters discs, but most version I've seen are pretty washed out. The mid-80's weren't a golden age for film stock.

That's true, maybe I should have bought a more recent movie for this test, e.g. Battle Los Angeles.

paradoxical

25th June 2013, 20:48

Who says that the "Mastered in 4K" Blu-ray Disc encodes actually are encoded in xvYCC?

Source please.

Sony does. If you want a source just search Sony's site for any of the Mastered in 4K discs and they talk about the expanded colors which is the xvYCC output such as the PS3 does. It's not our job to do your basic research. But if it is beyond your means to type in "Mastered in 4k and xvYCC" into Google here are a few of the many links you will find.

Sony’s “Mastered in 4K” Discs Support xvYCC Color (http://www.technologytell.com/hometech/96691/mastered-in-4k-discs-support-xvycc-color/)

From here (http://www.cnet.com.au/sony-mastered-in-4k-blu-rays-a-mixed-blessing-339344100.htm):

On the other hand, "mastered in 4K" Blu-rays also turn out to be the best picture quality ever produced on a Blu-ray disc, and will really look amazing when played on a Sony 4K TV.

There are three technical measures that elevate a "mastered in 4K" disc above the rest:

Enhanced bitrate: these discs exclude content extras in favour of using all available disc space to deliver the film in a greatly enhanced bitrate. Where most Blu-ray discs are typically delivered in rates in the 24Mbps to 30Mbps ballpark, these "mastered in 4K" discs deliver at 35Mbps to 38Mbps. A greater bitrate means a much clearer picture, and less moments where blocking or blurring will occur, particularly in action sequences.

XvYCC support: in the Blu-ray standard, xvYCC (also known as x.v.Color) is a colour space option that to date, has almost never been supported. XvYCC extends the available colour gamut to better represent the colour space that the original film was intended to be displayed at, while the standard sRGB space cuts off a lot of information in the red and blue-green sections of the spectrum. As long as your Blu-ray player and your TV support xvYCC, these discs will deliver a solid colour enhancement over other discs on the market.

Sony 4K algorithms: this final feature is a sweetener focused on giving Sony 4K TV owners a better experience with these discs than any other 4K TV owners. Being part of the same family, Sony Pictures and Sony Bravia have shared proprietary algorithm information to give the best possible upscaling performance on these films. Sony 4K televisions will be able to identify a "mastered in 4K" disc and use an upscaling algorithm based on the same formula used at Sony Pictures to downscale the film from 4K to HD. This secret sauce is likely to give a Sony TV the edge over other TVs that must use less-specific algorithms to upscale the content.

From here (http://www.highdefdigest.com/news/show/Mastered_in_4K/Industry_Trends/High-Def_Retailing/4K/UHDTV/Ultra_HD/Mastered_in_4K_and_the_Road_to_Ultra_HD/11781):

The packaging indicates that the expanded colors can be enabled through any xvYCC-compatible TV and Blu-ray player

SeeMoreDigital

25th June 2013, 21:53

I highly doubt that the official Blu-ray Disc specifications allow for xvYCC H.264 encoding, but not sure, so i asked in the more appropriate thread, see:

http://forum.doom9.org/showthread.php?p=1634217#post1634217Sufficed to say, it's Sony who are promoting and pushing this implementation.

You know Sony. They're the guys who created Blu-ray and the Blu-ray specification!

And if you refer to kabelbrand's post above, you'll find a link to some more information on Sony's web site!

paradoxical

25th June 2013, 22:44

I highly doubt that the official Blu-ray Disc specifications allow for xvYCC H.264 encoding, but not sure

Yes it most likely isn't. Hence why it requires both a Bluray player that specifically supports it and TV that can do xvYCC (for now pretty much only Sony equipment for both). Did you bother to even read the links I provided such as:

The packaging indicates that the expanded colors can be enabled through any xvYCC-compatible TV and Blu-ray player

paradoxical

25th June 2013, 23:37

But then it's not a Blu-ray Disc :p?

Sure it is. Hence the Blu-Ray logo and Sony calling them "Mastered in 4K Blu-Ray titles".

SONY PICTURES HOME ENTERTAINMENT ANNOUNCES "MASTERED IN 4K" BLU-RAY TITLES TIMED WITH SONY 4K TVs (https://blog.sony.com/press/sony-pictures-home-entertainment-announces-mastered-in-4k-blu-ray-titles-timed-with-sony-4k-tvs)

paradoxical

25th June 2013, 23:42

If the official Blu-ray Disc specifications do not allow xvYCC encoded video, then how can a disc containing xvYCC encoded video be a Blu-ray Disc?

It doesn't disallow it.

paradoxical

25th June 2013, 23:50

So xvYCC encoded video is guaranteed to be fully backwards-compatible with all Blu-ray Disc players?

Yes the discs are compatible with all players you just get regular gamut if it doesn't support xvYCC.

benwaggoner

26th June 2013, 20:29

Yes the discs are compatible with all players you just get regular gamut if it doesn't support xvYCC.
So how does it work then? The extended primaries get truncated or something? Or is it some kind of an enhancement layer? Multiple encodes?

I suppose it's time to transcend whatever latent remnants of HD DVD bitterness I have and pay more attention to Blu-ray :).

paradoxical

26th June 2013, 20:31

So how does it work then? The extended primaries get truncated or something? Or is it some kind of an enhancement layer? Multiple encodes?

I don't think anyone has analyzed a stream yet to know exactly. I assume it's some form of custom signaling or metadata that their players can read and is ignored by others. There's no way it can be multiple encodes when the other point of these discs are to increase the average bitrate.

paradoxical

26th June 2013, 20:33

To add from here (http://www.soundandvisionmag.com/blog/2013/05/29/blu-ray-review-spider-man-mastered-4k-version):

Other Blu-rays have been sourced from a 4K master, so what’s the big deal with these? A few things. First, the video bitrate has been upped considerably to ensure a solid, artifact-free picture: The new, Mastered in 4K Spider-Man maintains a steady 35 Mbps, as compared with the high-20 Mbps bitrate typical with other discs, including the 2012 Spider-Man Blu-ray. (Unfortunately, the increased video data rate means there’s no space for extra stuff like features and commentary tracks.) Second, Mastered in 4K discs incorporate something Sony calls Expanded Color, which otherwise goes by the name x.v.Color or xvYCC. To briefly sum up, discs with x.v.Color incorporate data describing colors outside the standard Rec.709 HDTV color space. When a Mastered in 4K disc is played on an x.v.Color-compatible BD player (according to Sony, only its own player line plus the PlayStation 3 can reliably be called compatible) and displayed on a TV capable of x.v.Color reproduction — Sony’s new W900A series HDTVs (look for my review in the June/July/August issue of Sound&Vision) and XBR-X900A Series 4K Ultra HD TVs, for example — you get the option to view this expanded range. And displaying it shouldn't involve any shift in the TV’s color points — the disc simply instructs the TV to “retrieve” those extra colors without distorting the set’s overall color balance.

There's not a whole lot of specifics though from what I've seen.

benwaggoner

26th June 2013, 21:43

To add from There's not a whole lot of specifics though from what I've seen.
There really aren't.

The only obvious way I see for them to do what they're doing would be to have a stock Rec. 709 encode and then some kind of enhancement later that added the (relatively small delta) of xvYCC data. Since it's mostly in chroma, that wouldn't be that many samples and they can be quantized quite coarsely. Perhaps using something like Scalable Video coding. I'd think the PS3 would likely have the horsepower to do something like this.

I am now very intrigued by this!

Also, other than Sony BD players, are there any known devices capable of xvYCC playout? It seems support is way more common in TV than it is in any way to play back the content. Can decoders internal to the TVs do the right thing with xvYCC bitstream?

IanB

26th June 2013, 23:00

benwaggoner

26th June 2013, 23:14

From what I understand Sony use the 1-15 and 241-254 chroma values to represent higher saturation colours. When you do the normal YUV->RGB translation you can end up with normalised colour values less then 0.0 or greater than 1.0, normal decoders clamp these values, advanced decoders map these values into a wider gamut colour space. The luma range is still 16-235.
That makes sense. But if chroma is getting clamped at those values, I worry we'll see posterization of chroma levels when the extended colors get clamped. A gradient of "very red" could turn into a flat area of just red without any detail. If there is some texture in the luma channel that might mask things, but still. It seems like it would be hard to make a "best of both worlds" encode like this.

IanB

27th June 2013, 01:25

benwaggoner

1st July 2013, 21:26

The out of gamut high saturation colours considered here would have been clamped in normal processing anyway, either by the source camera and/or the display device. The system just gives the opportunity to not clamp the very saturated colours when a high gamut source and display are available.
But if you allow out of range colors that will get clamped on some devices, it seems inevitable that you'll get posterization when it does wind up getting clamped.

IanB

2nd July 2013, 00:18

Yes, intuitively I agree there should be some sort of saturation posterization effect but how do you characterise and witness it.

We are talking about saturation getting clamped here, not luminance or hue. And saturation restriction happens with our simple trichromatic eyes.

The clamping happens in the YUV to RGB translation where you end up with normalised RGB values less then 0.0 or greater than 1.0 I tried an experiment using Limiter(0, 255, 31, 226) to knock another 15 off the normal chroma range and I cannot see any difference, which just probably means I do not have samples that sufficiently use the high saturation part of the existing gamut and/or a display that is not already more saturation challenged than the clamp.

I guess an extreme test case might involve some pure monochromatic light sources like sodium lamps, lasers, etc and a display version of the same. But our eyes cannot see spectrally pure colours as spectrally pure.

benwaggoner

2nd July 2013, 02:52

The clamping happens in the YUV to RGB translation where you end up with normalised RGB values less then 0.0 or greater than 1.0 I tried an experiment using Limiter(0, 255, 31, 226) to knock another 15 off the normal chroma range and I cannot see any difference, which just probably means I do not have samples that sufficiently use the high saturation part of the existing gamut and/or a display that is not already more saturation challenged than the clamp.
Yeah. Begging the question of whether xvYCC actually provides any viewer value for most real-world content. How different is the master, really, and for what content?

ChiDragon

2nd July 2013, 05:28

When I compared the new "Mastered in 4K" BD of the 2002 Spider-Man movie to the old disc, I found that there were more instances of >240 chroma (http://www.avsforum.com/t/1470744/avs-cant-wait-special-mastered-in-4k-blu-ray-releases/300#post_23325240) on the previous release than the xvYCC one.

It would be nice if they included some test content to verify the effects of the gamut expansion on your TV. There is a hidden video file but it's just a long, slow pan across a still image with no apparent usefulness.

benwaggoner

2nd July 2013, 17:18

When I compared the new "Mastered in 4K" BD of the 2002 Spider-Man movie to the old disc, I found that there were more instances of >240 chroma (http://www.avsforum.com/t/1470744/avs-cant-wait-special-mastered-in-4k-blu-ray-releases/300#post_23325240) on the previous release than the xvYCC one.

Huh.

Are there any discs that are known for particularly good use of xvYCC? Or even noticeable use?

SeeMoreDigital

2nd July 2013, 17:28

Huh.

Are there any discs that are known for particularly good use of xvYCC? Or even noticeable use?I'd go further...

I would like to know if there's anybody on this forum who has a 'xvYCC supporting' Sony Blu-ray player and TV? Because without these two supporting devices, nobody is going to 'see' any noticeable difference!

benwaggoner

19th July 2013, 19:30

Well, I've made myself a Rec. 2020 H.264 High 10 encode via x264!

Anyone have any idea what players actually know about Rec. 2020? I've got a Quadro K4000 plugged into a Dell U3011 30-bit display via DisplayPort, so I can render out 10-bit images via both DirectX and OpenGL. Dell claims it has a 120% gamut range based on the CIE1976 (83%) and CIE1931 (72%) test standards.

But what should be able to do the right thing here?

vivan

19th July 2013, 20:39

madVR

mp3dom

19th July 2013, 20:52

Since the topic also mentions greater color depth, I would like to point out the Panasonic "Master Grade Video Coding". There are not a lot of infos about it, but seems that the hint is to use the bluray MVC structure to use the base view as the standard image, and the dependent view for increase the bit depth of the video. Panasonic players with MGVC support should be able to 'merge' the MVC and outputs a 2D video with up to 12bit informations. Also, this method allows to fully use the 60 Mbps of the bluray 3D specs.
Here (http://www.phileweb.com/news/d-av/201304/10/32810.html) some explanation (JP)

sneaker_ger

19th July 2013, 22:15

madVR

madVR does not support output higher than 8 bit - just input. (Plus it only outputs RGB).

vivan

19th July 2013, 22:33

madVR does not support output higher than 8 bit - just input. (Plus it only outputs RGB).But it does support Rec. 2020. I doubt that any other renderer supports it. So it's better than nothing, right? :)

benwaggoner

20th July 2013, 00:30

drmpeg

20th July 2013, 01:49

Also, what's the proper --colormatrix setting for 10-bit Rec. 2020 (without expanded luma range)?

Using --colorprim bt2020 --transfer bt2020-10 are obvious, but I can't find any documentation on the difference between bt2020c and bt2020nc

bt2020c = constant luminance

bt2020nc = non-constant luminance

So for your example, bt2020nc would be correct.

Ron

benwaggoner

20th July 2013, 02:53

bt2020c = constant luminance

bt2020nc = non-constant luminance

So for your example, bt2020nc would be correct.
Why? I would have thought that "non-constant" would refer to the 12-bit mode with high dynamic range luma, which has a different, steeper gamma for high values.

drmpeg

20th July 2013, 03:56

Why? I would have thought that "non-constant" would refer to the 12-bit mode with high dynamic range luma, which has a different, steeper gamma for high values.

They're two different things. Transfer characteristics selects a gamma and matrix coefficients selects the way RGB is converted to/from YCbCr.

For the transfer characteristics (--transfer), bt2020-10 selects the normal gamma (same as BT.709) and bt2020-12 selects the steeper gamma.

For the matrix coefficients (--colormatrix), bt2020nc selects a non-constant luminance system (same as BT.709 but with different coefficients) and bt2020c selects a constant luminance system.

http://www.itu.int/rec/R-REC-BT.2020-0-201208-I/en

Ron

drmpeg

20th July 2013, 04:30

Here's a document that goes deep on the constant/non-constant luminance issue.

http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2246-2-2012-PDF-E.pdf

Ron

benwaggoner

20th July 2013, 21:24

Here's a document that goes deep on the constant/non-constant luminance issue.

http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2246-2-2012-PDF-E.pdf
Thanks. I'll check it out.

Lyris

22nd July 2013, 11:05

pandy

22nd July 2013, 11:24

(Plus it only outputs RGB).

Nope - you can use RGB output as YPbPr :

http://forum.doom9.org/showthread.php?p=1604899#post1604899
http://forum.doom9.org/showthread.php?p=1604480#post1604480

Any RGB video output can be turned to YPbPr.

foxyshadis

1st August 2013, 01:27

Here's a document that goes deep on the constant/non-constant luminance issue.

http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.2246-2-2012-PDF-E.pdf

Ron

Constant in this case means linear, right? Whoa, I had no idea 2020 supported that, and that actually makes 12- and 16-bit useful! Especially combined with the wider gamut. It really has everything a visual quality geek could want, I hope other color systems die in a hurry.

LigH

30th October 2015, 19:23

Since the topic also mentions greater color depth, I would like to point out the Panasonic "Master Grade Video Coding". There are not a lot of infos about it...

Some details and further links in English in the avsforum (http://www.avsforum.com/forum/114-hdtv-software-media-discussion/1486405-36-bit-mgvc-blu-ray-only-japan.html)

More details also in German in the bluray-disc.de lexikon (http://www.bluray-disc.de/lexikon/mgvc-master-grade-video-coding)

A thread in the VideoHelp forum (http://forum.videohelp.com/threads/374988-How-to-convert-bin-to-m2ts) pointed out that Studio Ghibli appears to sell some (but the thread starter may not have bought those, so, well ... at least this part of the thread is not a valid topic here).

Common Blu-ray players seem to handle the MVC stream but not the substream with additional color depth.

Balling

30th December 2020, 15:04

Lol, that is not that simple! First of all Y values of 16-235 can be more than 235 and should be presented, that is called Superwhite and has nothing to do with xvYCC. xvYCC may use 241-254 Cb, Cr (as 0 and 255 are reserved for synch in HDMI, but not reserved in files, of course), but that does not mean that values lower than 241 cannot be in xvYCC. For example, YCC=135,155,12 is translated into RGB=-43,184,184, that is in xvYCC. See https://www.avsforum.com/threads/xvycc-calibration.1170632/

SeeMoreDigital

30th December 2020, 15:21

Wow...

This topic was started way back in Oct 2012 and last posted in Oct 2015...

Things have moved on!

Balling

30th December 2020, 16:46

Wow...

This topic was started way back in Oct 2012 and last posted in Oct 2015...

Things have moved on!

No, they did not. Apple 4K TV uses xvYCC601 even for Dolby Vision. https://www.avsforum.com/threads/2020-lg-oled-cx-gx-owners-thread-faq-posts-1-6-no-price-talk.3119288/post-60360409