HDR10, Active HDR, Dolby Vision and other HDR schemes

Discussion in 'HD and UHD Flat Screen Displays' started by Robert Zohn, Jun 9, 2017.

  1. Robert Zohn

    Robert Zohn Active Member
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    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!
     
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  2. Sonnie

    Sonnie Senior Admin
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    I am still trying to get my head wrapped around all the 4K technobabble... so hopefully this thread will better help me understand it. Thanks for starting it.
     
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  3. Robert Zohn

    Robert Zohn Active Member
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  4. Robert, what is the latest discussion on how to best measure a display's ability to reproduce HDR or DV content, or for that matter dynamic range in general? It seems we need some scaleable measure or series of measures at different output densities.
     
  5. Robert Zohn

    Robert Zohn Active Member
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    We do sweeps of luminance levels at 10% intervals.

    The new hot method of measuring Color fidelity is called "Color Volume" and it measure color accuracy at all luminance levels in 10% intervals from 10% to 100%.
     
  6. Interesting. I haven't been paying much attention to image performance measures since I quit doing calibration 5 years ago. This was exactly what I had hoped would develop.
     
  7. Todd Anderson

    Todd Anderson News Editor / Reviewer/ Senior Admin
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    Thanks for starting this Robert. If changes were made to HDR10...what would be the difference between HDR10 and HDR10+? Sounds like they'd be similar in terms of carrying dynamic meta-data?

    What's really interesting is the potential damage this could do to Dobly Vision's current positioning to dominate the next gen of HDR encoding...I'm sure a lot of media creators would love to skip Dolby and use an open standard.
     
  8. Robert Zohn

    Robert Zohn Active Member
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    From what I am told "active" HDR10 works very much like the proposed HDR10+.

    On a somewhat related subject. Sony rolled out the HLG HDR upgrade with the recent Android 7.0 Nougat firmware update.

    Has anyone watched any HLG Youtube content on any of Sony's X1 Extreme processor equipped TV?
     
  9. Todd Anderson

    Todd Anderson News Editor / Reviewer/ Senior Admin
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    That's interesting... how will that work with existing HDMI connections? Doesn't the proposed HDR10+ require HDMI 2.1? I'm fairly certain it's only functionality will come through streaming direct to a TV (at the moment?).

    I've not seen HLG Youtube Content. But it sounds like you have a story to tell... how does it look?
     
  10. Jon Liu

    Jon Liu Active Member

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    Great topic. This is one of the most infuriating aspects of the newest technologies. All the different aspects of HDR. Not just the formats either, although thinking of Dolby Vision, HDR10 (now active HDR10), HDR10+, Technicolor HDR, HLG, the amount of information and misinformation surround them is just mind-boggling. There's still no standards on how TVs perform. HDR Premium certification doesn't seem to even mean that much. Tone mapping algorithms for different TVs are all over the place.

    Then there's WCG that's also lumped into the HDR moniker... which is a whole other ballgame as well.
     
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  11. Robert Zohn

    Robert Zohn Active Member
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    HDR10+ has not been adopted and we still do not know if it will go through. "Active HDR10" is happening now on select Sony and LG TVs.

    UHD/HLG on Youtube varies in pq from one feed to another. Some is excellent, but it varies wildly.

    Great post jon Lui. The new TV System is complex and covers, resolution, color gamut, 10-bit displays, EOTF and as you wisely said several variations of HDR.

    For a good overview of the new TV System I humbly suggest checking out my Power Point that I made for the NAB session I presented at in April 2017.
     
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  12. Todd Anderson

    Todd Anderson News Editor / Reviewer/ Senior Admin
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    I agree Jon. It's like Hi-Res audio on steroids.

    It's a shame that all of these technologies aren't open standards, because that would likely push us toward singular solutions more quickly...
     
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  13. Sonnie

    Sonnie Senior Admin
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    It seems like it's all just a big huge mess right now. Someone needs to get a grip on it all.

    It's bad enough that there are so many connection issues between components with HDCP 2.2... now to add all the different video technologies is getting seriously ridiculous.
     
  14. Todd Anderson

    Todd Anderson News Editor / Reviewer/ Senior Admin
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    Nice presentation Robert!
     
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  15. Jon Liu

    Jon Liu Active Member

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  16. Jon Liu

    Jon Liu Active Member

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    As far as HDR10+ adoption, all we have is Samsung and Amazon's collaboration on the Amazon App. Still not out yet, as I understand it, but that's the only "firm" thing we have for HDR10+.

    Sonnie's right, it's all a huge mess. HDMI connectivity issues is still a real problem that I think should have been sorted out long ago. ARC? Specs? Consistency? The idea behind HDMI is supposed to make things easier, but instead it makes things harder and worse.

    Now what's worse, we're finding out with Dolby Vision being available on disc, not only do the players and the TVs have DV capability, but Receivers, which can pass HDR10 just fine now to be upgraded to handle DV capability. It's just a matter of a firmware upgrade for them, but there already seems to be questions on which receivers will get an upgrade. And there's just been some general push back and knuckle dragging on the manufacturer's part to get any sort of confirmation out.
     
  17. WillHud

    WillHud New Member

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    I'm currently looking at getting a new tv. I'm looking at a couple different options. But one I'm really stuck on is the Active HDR and the regular HDR, what is the actual difference the two? Which one is better, the active one is cheaper so is it less effective HDR?
     
  18. JBrax

    JBrax Senior AV Addict
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    I've never heard of Active HDR? I tried googling it and couldn't really find much. It sounds a bit gimmicky though. What specific models are you looking at? Here's a good article that explains things for you. http://www.trustedreviews.com/opinion/hdr-tv-high-dynamic-television-explained-2927035
     
  19. Todd Anderson

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    Hi Will!

    Active HDR isn't a technical type of HDR... I'm guessing you've seen this associated with LG televisions?

    If so, I believe LG is calling the form of HDR performance offered by a technology called "Dolby Vision" to be "active" because it uses dynamic metadata encoded into the video stream that allows for color and brightness to be adjusted on a frame-by-frame basis. HDR-10, on the other hand, uses a static metadata that's applied at the beginning of video and doesn't change.

    HDR-10 and HLG are both going to be the most prevalent forms of HDR used on broadcast TV. You'll find Dolby Vision (which is far less prevalent at this time) to be used with some streaming content and disc based content.

    Remember: Just because a TV is labeled as offering Dolby Vision, you have to feed it Dolby Vision content to take advantage of it.

    Dolby Vision offers far superior performance to HDR-10 in other areas, including 12-bit color (versus 10-bit color)...BUT, any television you buy that carries Dolby Vision will also offer HDR-10 performance... and (I believe) most moderately-priced and expensive TVs also now ship with HLG.

    Which TVs are you looking at?
     
  20. WillHud

    WillHud New Member

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  21. Todd Anderson

    Todd Anderson News Editor / Reviewer/ Senior Admin
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    Ah... yes.

    The world of HDR and all of the different versions of HDR can be very confusing. Top it off with the fact that manufacturers sprinkle their own marketing-speak to try and differentiate themselves from each other, and you have a recipe for true confusion.

    The price differences you're seeing between the LG televisions probably have to do with the kind of television panel technology they use. That link you provided is for an LCD panel television (that has LED backlighting... hence the use of "LED" in the product description). I'd guess the other sets you're looking at are OLED panel televisions?

    Very big differences between those two technologies.

    You can find very expensive LCD/LED panel TVs, too. But, in general, the OLED TVs are going to cost more.
     

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