WHAT IS HDR VIDEO?

[John Shofner]

Part 3! Part 3!

 

[Samuel Bilodeau]

Sorry, but hat information is incorrect. Dolby PRM-4220 is an SDR monitor. Even though it is capable of 600 nits, it doesn't mean that it is an HDR monitor. People frequently confuse brightness with HDR.

Because of its high brightness output and 12 bit panel you can cheat its dynamic range by scaling SMPTE ST2084 into Gamma 2.4 with a LUT on the display that will effectively give it the HDR EOTF scaled into the display's native brightness range. You're right though, I probably shouldn't refer to it as HDR directly, though there is a workaround that can cheat its HDR.

The Dolby monitors that are HDR capable are Pulsar (4000 nits) and the newer and less expensive one as well, that I can't remember the name right now.
At this time Sony X300 is the only professional monitor, that you can actually purchase, unlike Dolby's monitors. And because of that, even though it is $30k, it is slowly becoming a standard for HDR mastering around the world.

I've added an addendum to the post to clarify.

 

[Samuel Bilodeau]

Part 3! Part 3!

Part 3! http://www.mysterybox.us/blog/2016/10/19/hdr-video-part-3-hdr-video-terms-explained

 

[Samuel Bilodeau]

This is really good but as a founding member of the Secret Society of Pedantic Gamma Cultists I cringe at your portrayal of different gamma spaces.

Gamma should never affect how you aesthetically see an image. If two different gamma encodings look aesthetically different someone fucked up. The point of gamma is to avoid quantization and banding... period. The idea is that whatever gamma you encode an image in should be reversible and therefore ultimately irrelevant. Gamma should be invisible to everybody in the entire imaging pipeline except to automagically reduce banding and even then a good dithering engine should hide all but the most difficult cases.

I completely agree - I'm not sure which part gave you the impression that I was implying something different. If there's a specific paragraph or part I can revise to prevent confusion let me know!

Edit: Just one editorial note, I'm not sure if you were just trying to illustrate the concept but if you were hoping to be exact: your bit depth gradient scale actually shows 8, 9 and 10 bit relative to one another. 2^n doubles with every bit so 10 bits would be 4x as many gradient steps as 8 bit and 12 bit would be 16x as many.

Yup. That's my bad. I'll get a new graphic up there as soon as I can. Thanks for the feedback!

 

[jake blackstone]

Because of its high brightness output and 12 bit panel you can cheat its dynamic range by scaling SMPTE ST2084 into Gamma 2.4 with a LUT on the display that will effectively give it the HDR EOTF scaled into the display's native brightness range. You're right though, I probably shouldn't refer to it as HDR directly, though there is a workaround that can cheat its HDR.

For that much money ($30k+), I'd rather buy X300, that is a true 4k HDR monitor and it doesn't require a cheat. 600 nits is not enough for a true HDR requirements, as only OLED can meet HDR recommendation at 540 nits maximum brightness. SDR Dolby monitor is LCD with local dimming, so that wouldn't work either. The blacks are nowhere near the OLED levels.

 

[Stacey Spears]

600 nits is not enough for a true HDR requirements, as only OLED can meet HDR recommendation at 540 nits maximum brightness.

There is a large group of people that believe 1000 nits is all you need for HDR. To me, HDR begins at 1000 for LCD. OLED is the exception. The 540 nits is more for edge lit LCDs. OLED already exceeds the lower end UHDA limits.

Cinema does an HDR grade at 100 nits. They do not scale ST2048 to fit 100 nits, they treat it as it should be, an absolute EOTF.

For those interested, I wrote a simple Windows command line tool that will convert a nit into a bitlevel. It currently uses limited range because that is what is delivered to the consumer. I will add a switch later to convert into full range. I will also add the inverse to go bits into nits.

SDR Dolby monitor is LCD with local dimming, so that wouldn't work either. The blacks are nowhere near the OLED levels.

The Dolby Maui is a 2000 nit LCD and its black level is not great either. The PRM has much a better black level. Last time I checked, the Pulsar consumes around 32-amps.

I have posted this graph before. The BVM is called out so you can see how it performs. The top line in the graph is the Sony 65" Z9D. Sony recently added a hard clip mode. In one mode it will hard clip at 1000 nits to behave like the BVM. In the other modes it tone maps as a consumer display should.

 

[Samuel Bilodeau]

For that much money ($30k+), I'd rather buy X300, that is a true 4k HDR monitor and it doesn't require a cheat. 600 nits is not enough for a true HDR requirements, as only OLED can meet HDR recommendation at 540 nits maximum brightness. SDR Dolby monitor is LCD with local dimming, so that wouldn't work either. The blacks are nowhere near the OLED levels.

Completely agree.

 

[Samuel Bilodeau]

For those interested, I wrote a simple Windows command line tool that will convert a nit into a bitlevel. It currently uses limited range because that is what is delivered to the consumer. I will add a switch later to convert into full range. I will also add the inverse to go bits into nits.

That's a useful little tool! Thanks for it, and keep me posted when you get it updated!

 

[Stacey Spears]

Here is another Windows command line tool. This one will take the 26-byte hex string from HDfury and convert back into English. I have captured the HDR Info from most UHD BDs, Netflix and Amazon. I would say all of the color primaries are incorrect. They are all using the theoritecal P3 primaries instead of the actual primaries of the mastering display. e.g. No two BVMs have measured exactly the same. They are very close. Not a big deal today with being 99% P3. Will be an issue when a display is somewhere between P3 and 2020.

 

[Marc Wielage]

The Dolby Maui is a 2000 nit LCD and its black level is not great either. The PRM has much a better black level. Last time I checked, the Pulsar consumes around 32-amps.

Thanks for the clarification, Stacey. Does Dolby publish the specs for Pulsar or Maui anywhere?

Ultra mega super extra ultra hyper. 4000 nits is garbage, that's not even 10000. If I don't see an 80KW truck parked in front of the studio, I'm not even entering a grading suite and taking my welding glasses elsewhere.

I have to admit, the prospect of staring into the firey hell of 4000 nits for 10-12 hours a day is daunting. In truth, my eyes get tired after 4-5 hours of continuous 100 nits. I just had my eyes examined a week ago (true story), and the doctor told me one my problems is that I don't blink enough. "Colorists never blink" is what I replied to him. (Color acuity was perfect according to his tests, BTW.)

 

[Hrvoje Simic]

I have to admit, the prospect of staring into the firey hell of 4000 nits for 10-12 hours a day is daunting. In truth, my eyes get tired after 4-5 hours of continuous 100 nits.

"No, shut up shut up shut up, I hate you, it's awesome, I want more more more. "

I just had my eyes examined a week ago (true story), and the doctor told me one my problems is that I don't blink enough. "Colorists never blink" is what I replied to him. (Color acuity was perfect according to his tests, BTW.)

I'm considering an alarm every x minutes for a brake and reducing the screen estate.

 

[Samuel Bilodeau]

In truth, my eyes get tired after 4-5 hours of continuous 100 nits. I just had my eyes examined a week ago (true story), and the doctor told me one my problems is that I don't blink enough. "Colorists never blink" is what I replied to him. (Color acuity was perfect according to his tests, BTW.)

My optometrist told me the exact same thing. Near the end of last year, my dry eyes from coloring had gotten so bad that I couldn't actually see properly driving home at night. I started using my old Gunnars (Crystalline lens series), which I hadn't used in a while, and it helped keep my eyes moist and able to focus, though their +0.25 diopter was annoying. I've since switched to prescription Gunnars and they're the best glasses I've ever owned - they use Zeiss optics and their premium lineup has as close to zero optical distortion that I've ever seen in a set of glasses; their Crystalline lenses are designed for graphic designers, photographers, and colorists who need zero color distortion (and that claim holds up, IMO). Can't recommend them enough.