HDR10, Active HDR, Dolby Vision and other HDR schemes

[Robert Zohn]

I'm starting this thread for three reasons.

First, it's among the hottest, most discussed, and somewhat misunderstood but highly relevant subject to the new TV System that we are all beginning to embrace with significant growth among novices and enthusiasts alike.

Second, we have several HDR protocols and even requests from some manufacturers for changes to the SMPTE base standard HDR10 to add dynamic metadata and others who want to make it active without a standards change.

Third, is the misunderstanding of how HDR capable TVs tone map the various HDR systems to their luminance abilities.

Here's a kick start to this complex and fascinating subject.

Samsung has proposed a change to the SMPTE ST.2086 base standard HDR10 by adding dynamic metadata so it can perform much like Dolby Vision. Another very similar method that measures each frame on the fly and tone map the display to it's brightness capability, which is commonly called "active HDR".

LG and Sony are doing "active HDR" with the current base standard HDR10 on all of the 2017 X1 Extreme processor TVs, like the A1E OLED, Z9D, X940E and X930E, and LG employs a very similar active HDR10 processing with their SJ9500, C7, E7, G7 and W7 OLED TVs.

As I am more familiar with how Sony's active HDR10 operates I'll keep my comments to Sony's 2017 X1 Extreme models. You might notice very little difference between Dolby Vision and HDR10 on Sony's X1E equipped TVs. Sony HDR TVs don’t use the static brightness metadata in HDR10 (MaxCLL, MaxFALL) they actually measured brightness frame by frame and generate dynamic metadata for HDR10 content.

MaxFALL, stands for "Maximum Frame/Average Light Level" and MaxFALL corresponds to the highest frame average brightness of one frame from the entire content.

MaxCLL, is the Maximum Content Light Level and is an additional static HDR metadata that represents and measures the brightest pixel of the entire content.

In part this explains why the standard 10% peak luminance window test pattern may measure a lower peak luminance than what the display is actually capable to deliver when we view actual HDR content that only use a far smaller area of the screen with the HDR specular highlights that typically occupy less than 1% of the display.

This HDR anomaly is most noticeable when the content is mastered at 4k nits. In Sony's new 2017 X1 Extreme processor TVs the HDR algorithms are tuned to apply tone mapping (which reduces screen brightness and accuracy) when the brightness of the frame exceeds the TV set’s capabilities. It is then applied to ensure HDR highlights are properly displayed.

Let the discussion begin!

[Jodi]

Originally Posted by Robert Zohn

I'm starting this thread for three reasons.

First, it's among the hottest, most discussed, and somewhat misunderstood but highly relevant subject to the new TV System that we are all beginning to embrace with significant growth among novices and enthusiasts alike.

Second, we have several HDR protocols and even requests from some manufacturers for changes to the SMPTE base standard HDR10 to add dynamic metadata and others who want to make it active without a standards change.

Third, is the misunderstanding of how HDR capable TVs tone map the various HDR systems to their luminance abilities.

Here's a kick start to this complex and fascinating subject.

Samsung has proposed a change to the SMPTE ST.2086 base standard HDR10 by adding dynamic metadata so it can perform much like Dolby Vision. Another very similar method that measures each frame on the fly and tone map the display to it's brightness capability, which is commonly called "active HDR".

LG and Sony are doing "active HDR" with the current base standard HDR10 on all of the 2017 X1 Extreme processor TVs, like the A1E OLED, Z9D, X940E and X930E, and LG employs a very similar active HDR10 processing with their SJ9500, C7, E7, G7 and W7 OLED TVs.

As I am more familiar with how Sony's active HDR10 operates I'll keep my comments to Sony's 2017 X1 Extreme models. You might notice very little difference between Dolby Vision and HDR10 on Sony's X1E equipped TVs. Sony HDR TVs don’t use the static brightness metadata in HDR10 (MaxCLL, MaxFALL) they actually measured brightness frame by frame and generate dynamic metadata for HDR10 content.

MaxFALL, stands for "Maximum Frame/Average Light Level" and MaxFALL corresponds to the highest frame average brightness of one frame from the entire content.

MaxCLL, is the Maximum Content Light Level and is an additional static HDR metadata that represents and measures the brightest pixel of the entire content.

In part this explains why the standard 10% peak luminance window test pattern may measure a lower peak luminance than what the display is actually capable to deliver when we view actual HDR content that only use a far smaller area of the screen with the HDR specular highlights that typically occupy less than 1% of the display.

This HDR anomaly is most noticeable when the content is mastered at 4k nits. In Sony's new 2017 X1 Extreme processor TVs the HDR algorithms are tuned to apply tone mapping (which reduces screen brightness and accuracy) when the brightness of the frame exceeds the TV set’s capabilities. It is then applied to ensure HDR highlights are properly displayed.

Let the discussion begin!

While I don't have time right now to make any comments, I do think this information is very helpful, very interesting, and will be the subject of much conversation among us forum members. This is a great springboard from which to start up insightful conversations, comments, etc.

Will chime in sometime next week.....

[PaulGo]

To me what is important is the end result. I do prefer a open standard which manufactures can apply without paying fees. If the Sony / LG method can give similar (in the ballpark) results to the Samsung proposal I would prefer the Sony method.

[Geoff D]

Robert: Is it only the 2017 X1E models that can do that? Or the ZD9 too? Alls I know is my ZD9 is an absolute champ when it comes to HDR10 mapping, and on my last calibration run it kicked out just under 1900 nits peak on a 10% window. Love dis TV and seeing Dolby Vision on it is going to be very interesting indeed.

[Robert Zohn]

Sorry for saying "2017" X1 Extreme processor TVs. My bad.

All of Sony's active HDR benefits are built-into Sony's 2016 mid year flagship TV.

[LordoftheRings]

Robert, thank you. This is going to be a great informative thread for all of us.

[Penton-Man]

Originally Posted by Robert Zohn

Samsung has proposed a change to the SMPTE ST.2086 base standard HDR10 by adding dynamic metadata so it can perform...

In the works

[TM2-Megatron]

It's too bad LG can't add that active HDR to their 2016 OLEDs... the E and G series at least, with their more powerful SoCs.

[FilmFreakosaurus]

And yet, besides dynamic HDR, Dolby Vision has 12 bit depth and higher chroma sampling than HDR10 (and maybe HDR10+), which seems to be one of the more forward thinking approaches so far as long as the studios follow the correct encoding and mastering standards.

Why the BDA didn't just mandate 12 bit, 4:2:2 and higher as a base standard to begin with... Though, Universal would probably still find a way to screw even that up.

[Geoff D]

Originally Posted by FilmFreakosaurus

And yet, besides dynamic HDR, Dolby Vision has 12 bit depth and higher chroma sampling than HDR10 (and maybe HDR10+), which seems to be one of the more forward thinking approaches so far as long as the studios follow the correct encoding and mastering standards.

Why the BDA didn't just mandate 12 bit, 4:2:2 and higher as a base standard to begin with... Though, Universal would probably still find a way to screw even that up.

If we got a new disc storage format then perhaps they would've started with 12-bit as a base, but with a mere extension to the BD spec for that 100GB maximum then it was always likely to be at the lower end. Perhaps if Dolby's special quart-in-a-pint-pot processing was actually embraced as the standard from the start (it's only optional on UHD Blu, after all) then we could've had all that, but it wasn't so we didn't. Personally I'm still staggered by how good HDR10 can look so DV will be the cherry on top.

Originally Posted by Robert Zohn

Sorry for saying "2017" X1 Extreme processor TVs. My bad.

All of Sony's active HDR benefits are built-into Sony's 2016 mid year flagship TV.

Yes, I remember matey from Sony talking about this active presentation in that AVS interview, it maps when it needs to map but is intelligent enough to recognise when it doesn't need to, correct?

[Zhorik]

Originally Posted by FilmFreakosaurus

And yet, besides dynamic HDR, Dolby Vision has 12 bit depth and higher chroma sampling than HDR10 (and maybe HDR10+), which seems to be one of the more forward thinking approaches so far as long as the studios follow the correct encoding and mastering standards.

Why the BDA didn't just mandate 12 bit, 4:2:2 and higher as a base standard to begin with... Though, Universal would probably still find a way to screw even that up.

Wasn't it mentioned in the HDR thread that HDR-10 can do 4:2:2?

[Robert Zohn]

Originally Posted by FilmFreakosaurus

And yet, besides dynamic HDR, Dolby Vision has 12 bit depth and higher chroma sampling than HDR10 (and maybe HDR10+), which seems to be one of the more forward thinking approaches so far as long as the studios follow the correct encoding and mastering standards.

Why the BDA didn't just mandate 12 bit, 4:2:2 and higher as a base standard to begin with... Though, Universal would probably still find a way to screw even that up.

All true, but no TV panel is 12bit so DV's 12bit and better color sampling is thrown out. With that said, I would think it might have some value to have higher chroma sampling and bit depth before the signal gets to the panel.

[BozQ]

Thanks very much for this. I'll take my time to read later.

[Geoff D]

Originally Posted by Zhorik

Wasn't it mentioned in the HDR thread that HDR-10 can do 4:2:2?

Of course it can, it can also do 4:4:4, but the salient point is that this is not featured in the UHD Blu-ray specification itself which is the limiting factor here, not HDR10 as a format. And while Dolby are reverse engineering a 4:2:2 output from a 4:2:0 2160p base layer combined with a 4:2:2 1080p enhancement layer, that's decidedly not the same thing as encoding a 2160p 4:2:2 signal directly to disc.

[StingingVelvet]

Very real possibility that Dolby Vision and HDR10+ streams will have 12 bit color and such eventually while the discs are down-converted to 10?

[JohnAV]

Originally Posted by StingingVelvet

Very real possibility that Dolby Vision and HDR10+ streams will have 12 bit color and such eventually while the discs are down-converted to 10?

HDR10+ is still 10 bit, its a extension (adding dynamic metadata) to HDR10. Dolby Vision discs such as Despicable Me in DV mode is 12 bit color played from media, would be the same if streamed.

[eddievanhalen]

Do domestic 12 bit panels exist?

[Robert Zohn]

Not in the ^ consumer market.

[eddievanhalen]

Then My bets are with HDR10+,it makes more sense to me than Dolby Vision. I think 12 bit panel willtake some time to de affordable on the consumer market and despite all the metadata DV has to optimize the display panel one's using I don't want a 12 to 10 bit, dithered or not convertion.
HDR10+ for the moment is the one togo with IMO.

[FilmFreakosaurus]

Originally Posted by eddievanhalen

Then My bets are with HDR10+,it makes more sense to me than Dolby Vision. I think 12 bit panel willtake some time to de affordable on the consumer market and despite all the metadata DV has to optimize the display panel one's using I don't want a 12 to 10 bit, dithered or not convertion.
HDR10+ for the moment is the one togo with IMO.

If they don't upgrade HDR10+ to 12 bit and higher chroma sampling, I would still go with DV. You don't want banding do you?