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Any thoughts on HDR?


Frank Hegyi

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I saw some HDR monitors and TVs at a Sony event last night. They looked really incredible. The difference between SDR and HDR is almost like wiping the fog off a window. We can finally see the dynamic range of all these awesome cameras.

 

It's also going to change the way we shoot. One example: in SDR, blown out practicals at 100IRE aren't that much brighter than the rest of the scene, but the HDR displays get sooo bright, practicals look like a real light source. It actually hurts your eyes.

 

Anyone else have any HDR thoughts?

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I think there are some good things about HDR -- ability to hold detail in bright areas like curtain sheers with sun on them, practicals, etc. Greater depth to the image because of increased contrast range. Will be great for nature documentaries like a Planet Earth-type series.

 

The downside is that it takes the image a little further away from being a traditional film look, even though a projected print had more contrast range than digital projectors can achieve, we didn't see 15-stops of detail in that print. So it takes images closer to an immersive hyper-reality that is great for some projects but less necessary for others that are opting for a traditional "movie" look, particularly if they are aiming to be reminiscent of a 1970's movie, let's say. It would be hard to create the feeling of "The Godfather" with its dim highlights if the brightest parts of the frame are hitting 1000 nits. It also makes it a bit harder to achieve a higher contrast look like silhouettes, etc. if all 15-stops of information in your recording will be displayed on the screen -- you'll have to work a lot harder to get details to fall off to black.

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Lots of thoughts.

 

One of the principal ones is that the professional displays look spectacular, but the domestic TVs are generally underwhelming. At a Sony event, you probably saw the BVM-X300, which is an OLED capable of 1500 nits and therefore one of the most capable video displays in the world at present. It looks spectacular; Dolby's Pulsar displays, at 4000 nits with the minor handicap of imperfect TFT blacks, look even better.

 

The problem is that a lot of domestic TVs have been considerably brighter than the hundred-ish nits of standard Rec. 709 (by reference to Rec. 1886) for some time. Computer monitors are often 500-600 with the controls maxed out, mainly since they use broadly the same backlight and TFT panel technology as the computer displays and brighter sells.

 

Some standards propose that HDR for domestic displays begins at 1000 nits, which is less than a stop brighter than some TVs already are.

 

The thing to bear in mind about cinematic HDR is that the standards for projection are much dimmer than those for monitors, so it isn't quite the same thing. An OLED-based domestic TV is already considerably HDR-er than cinema.

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Both IMAX and Dolby laser projectors claim to be HDR, even though I have yet to see any HDR content that looks good on them. I think the big thing is lumens as Phil points out. That's why you really need a bright light source and lasers are the only thing that can deliver it right now.

 

I will reiterate as phil said; most of what you see in the SDR vs HDR is Rec709 vs Rec2020. Sure the lumens are an issue, but that's just a matter of a brighter backlight on LCD sets, rather then a technology change like OLED vs LCD.

 

I'm personally not a fan of the current flock of OLED sets. Like DLP projectors, there are black lines between each pixel and that grid is visible from a normal viewing range. Its the same in movie theaters with DLP projectors, they resolve this issue by softening the focus on the projectors, a clever little trick most people don't realize is happening. Can't do that with OLED sets...

 

So where the technology is cool, I don't see it gaining ground like 1080p has. The broadcasters are still using old 8 bit 4:2:0 19mbps transport stream technology and updating to 50Mbps for 10 bit 4:2:2 4k transport stream, is going to be a challenge. There is a limit to how much bandwidth you can squeeze down a pipe and currently, the cable, satellite and over the air brodcasters are maxing it out, throttling back certain content in order to get higher 38Mbps streams on other networks for special events. Unfortunately, streaming from satellite, cable and over the airwaves, is where .h265 struggles. However, over the internet with buffering, .h265 works great and it has a Rec2020 provision. So we'll see HDR content streaming online first. The big question is... who will pay for all that bandwidth.

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I saw some HDR monitors and TVs at a Sony event last night. They looked really incredible. The difference between SDR and HDR is almost like wiping the fog off a window. We can finally see the dynamic range of all these awesome cameras.

 

It's also going to change the way we shoot. One example: in SDR, blown out practicals at 100IRE aren't that much brighter than the rest of the scene, but the HDR displays get sooo bright, practicals look like a real light source. It actually hurts your eyes.

 

Anyone else have any HDR thoughts?

My gut reaction to HDR viewing...

1. A small bright screen in a very large dark space will be difficult to watch for long periods. Either from the back of a theater, or even a 50" screen in a dark living room. So, for a theater, the screen will need to fill much of the peripheral vision. For the home, some ambient light behind the screen may be necessary to avoid fatigue while watching.

2. It's not ever required to use the entire HDR range in an image. A little, can go a long way.

3. HDR will require a separate pass for color grading, and maybe a special version for theaters vs home HDR as well.

4. I think, when shooting for HDR release, I'm going to test out a bunch of frosty filters for the lens. If I'm getting really good blacks, I may wish to see some light spill into larger dark areas of the frame.

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So where the technology is cool, I don't see it gaining ground like 1080p has. The broadcasters are still using old 8 bit 4:2:0 19mbps transport stream technology and updating to 50Mbps for 10 bit 4:2:2 4k transport stream, is going to be a challenge. There is a limit to how much bandwidth you can squeeze down a pipe and currently, the cable, satellite and over the air brodcasters are maxing it out, throttling back certain content in order to get higher 38Mbps streams on other networks for special events. Unfortunately, streaming from satellite, cable and over the airwaves, is where .h265 struggles. However, over the internet with buffering, .h265 works great and it has a Rec2020 provision. So we'll see HDR content streaming online first. The big question is... who will pay for all that bandwidth.

 

I'm curious to see what the traditional broadcasters do. Looks like Netflix and Amazon are jumping on the 4K HDR train. It won't be good for the traditional broadcasters if Netflix can say, "we're cheaper, more convenient, and the only way to use the features on your fancy new TV.

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The ability of the OTT distributors to change their software very quickly allows them to react with incredible speed to new technologies, in comparison to the old guard. I think that's what'll make the big difference, long term.

 

P

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My gut reaction to HDR viewing...

1. A small bright screen in a very large dark space will be difficult to watch for long periods. Either from the back of a theater, or even a 50" screen in a dark living room. So, for a theater, the screen will need to fill much of the peripheral vision. For the home, some ambient light behind the screen may be necessary to avoid fatigue while watching.

2. It's not ever required to use the entire HDR range in an image. A little, can go a long way.

3. HDR will require a separate pass for color grading, and maybe a special version for theaters vs home HDR as well.

4. I think, when shooting for HDR release, I'm going to test out a bunch of frosty filters for the lens. If I'm getting really good blacks, I may wish to see some light spill into larger dark areas of the frame.

 

All good points. I was definitely getting some eye fatigue after only 1.5 hours with the HDR in a dark room.

 

From the little bit that I've seen, the best uses of the extra dynamic range save the large majority of the top end for highlights (reflections, light sources, clouds, etc.) But all this discussion has me imagining a replay of the advertising "loudness wars" when all the TV advertisers over-compressed their audio tracks in an attempt to be the loudest commercial. I can definitely imagine watching a stunning episode of Planet Earth 2 on Discovery Channel HDR, but then a Tide commercial comes on were they've taken a low contrast scene and stretched it out over the entire dynamic range of the TV, burning everyone's eyeballs out of their head in a misguided attempt to be the brightest commercial.

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I'm curious to see what the traditional broadcasters do. Looks like Netflix and Amazon are jumping on the 4K HDR train. It won't be good for the traditional broadcasters if Netflix can say, "we're cheaper, more convenient, and the only way to use the features on your fancy new TV.

Yep... I just don't think traditional broadcasts can do much. The move to HD was subsidized and they don't have the kind of money to keep upgrading. Sure, the national infrastructure can support higher bandwidth content, the Superbowl for instance is broadcast in 4k, but only for special satellite services. It's easy to rent a 4k truck, it's easy to send that high bitrate content via satellite, but it's hard to get it to all the consumers.

 

I personally feel traditional broadcasting is on the way out, so what happens in the next 10 - 20 years is going to be very interesting.

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I think there are some good things about HDR -- ability to hold detail in bright areas like curtain sheers with sun on them, practicals, etc. Greater depth to the image because of increased contrast range. Will be great for nature documentaries like a Planet Earth-type series.

 

The downside is that it takes the image a little further away from being a traditional film look, even though a projected print had more contrast range than digital projectors can achieve, we didn't see 15-stops of detail in that print. So it takes images closer to an immersive hyper-reality that is great for some projects but less necessary for others that are opting for a traditional "movie" look, particularly if they are aiming to be reminiscent of a 1970's movie, let's say. It would be hard to create the feeling of "The Godfather" with its dim highlights if the brightest parts of the frame are hitting 1000 nits. It also makes it a bit harder to achieve a higher contrast look like silhouettes, etc. if all 15-stops of information in your recording will be displayed on the screen -- you'll have to work a lot harder to get details to fall off to black.

 

This is a all really interesting and a good point - but wouldn't it be possible to still limit the dynamic range of a given film, scene, or even a shot if you wanted to retain an older style look?

 

with HDR you have more information so similar to shooting on a higher end camera maybe it can open up new creative options.

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We did an HDR timing pass on my last movie. It was fantastic to be able to see detail in both shadows and highlights at the same time. The shadows, in particular, had 3 dimensional quality which was interesting. Sadly, the only time most of that additional detail is visible is when watching on an extremely expensive monitor, in a perfectly dark room. I think it's an interesting technology, but it's hard to tell if it will become more widespread.

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Within limits, you could crush the shadow detail down, you could grey-out and clip your whites below 100%, etc. but go too far and it starts to look artificial. And of course, it begs the question of what's the point of making an HDR version if it just looks like an SDR image?

 

 

This is a all really interesting and a good point - but wouldn't it be possible to still limit the dynamic range of a given film, scene, or even a shot if you wanted to retain an older style look?

 

It's also brings up another issue, similar to current issues with separate timings for 3D, different display gammas that the material is being viewed on, etc. which is the notion of whether it is a good idea to have different-looking versions of the same work of art. Maybe that's just an old-fashioned idea that has to be abandoned but I've never been fond of the notion of people watching versions of my movies with different looks involved.

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It's also brings up another issue, similar to current issues with separate timings for 3D, different display gammas that the material is being viewed on, etc. which is the notion of whether it is a good idea to have different-looking versions of the same work of art. Maybe that's just an old-fashioned idea that has to be abandoned but I've never been fond of the notion of people watching versions of my movies with different looks involved.

 

That's a very good question that will probably never be completely answered, but maybe we can see a bit of the future by considering other mediums that have been through similar situations.

 

The web design world went through this 5-10 years ago with the rise of smartphones and tablets. Pre-iPhone, web designers could almost guarantee their work would be viewed at a screen resolution of at least 1024x768px, so the large majority of websites had a fixed width of 960px. That all changed with the smartphones. It was obvious the design community had to accommodate the narrower screen sizes, but there were competing schools of thought on how. One was to use metadata from the user's device to serve them a completely separate "mobile" website which was optimized for the narrow screen width with limited functionality. That strategy has largely faded away. Today, the generally accepted practice is called "responsive web design." I'm sure you've noticed websites that change layouts as you change the size of your browser window. Boston city hall even got into the game recently. Try it out. https://www.boston.gov/ It was a pretty massive mindset switch for the design community to accept that they'll never be able to control how their work is actually viewed.

 

Another medium that comes to mind is music. I don't know if you've ever sat in on a "mastering" session for an album, but it's kind of similar to the HDR situation. "Mastering" is the final part of the recording process. It determines how loud a recording is (compression), the mix between bass, mids, and treble (kinda like color timing), and sometimes reverb. One of the jobs of the mastering engineer is to make sure the recording sounds good on any type of speaker. A good mastering room has a bunch of different speakers built into the wall. Everything from professional monitors that cost thousands of dollars to a pair of apple headphones. The mastering engineer will be constantly switching back and forth between all the different speakers in an attempt to strike a balance between all the different listening possibilities. There will even be the obligatory car test, when you burn a CD and drive around the block while listening. You can hear the effect this process has had on music over time. Steely Dan made records, designed to be played on a record player in your living room with a pair of relatively nice speakers. Modern bands don't know where you're going to listen to their music. If you buy a Muse album on vinyl, it sounds pretty terrible. It's not because sound engineers in the 70's knew something we don't know today. It's because the Muse album was engineered to be listened to on the bus. If you try to listen to Steely Dan on the bus with apple headphones, you can't hear anything. It's not loud enough. Now that vinyl sales have made a pretty significant come back, you'll see a lot of bands doing separate mastering passes for digital and vinyl. Not because the formats need it, but because the listening environments are so dramatically different.

 

The last example I can think of is video games. If you play any games on your computer, you're familiar with the resolution settings. A lot of games have fine control over the graphics settings to allow them to be played on older computers. You can go into the menus and individually turn off things like, shadows, rain, lightning effects, frame rate, etc. That has a huge effect on what the game looks like. I also heard an interesting interview recently with a video game preservationist who is trying to figure out how to deal with software updates which have become so prevalent. The Super Mario Brothers cartridge that shipped to stores never changed. The game was the game. But nowadays, games are constantly updated through software updates. The Rocket League that was released on day 1 is totally different from the Rocket League that exists today. But which version is the "real" version. And how are you supposed to preserve something that's constantly changing. An even bigger problem are games that are run like services. World of Warcraft only works while the company keeps their servers up and running. That game is a huge cultural artifact, but when the company inevitably shuts down the servers some day, will that artifact be lost forever? What even is World of Warcraft if no one is playing it? It's a social game. It derives it's value from the other players playing it.

 

All hard questions.

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I'm curious to see what the traditional broadcasters do. Looks like Netflix and Amazon are jumping on the 4K HDR train. It won't be good for the traditional broadcasters if Netflix can say, "we're cheaper, more convenient, and the only way to use the features on your fancy new TV.

Currently there is a transition from DVB-T to DVB-T2 in PAL countries, in the US and other NTSC countries it is ATSC-3.

 

These standards have the provision for 4K at some bit rate... but... at the same time there has been a movement around the world to 'repack' current over-the-air broadcast into fewer channels.

 

So, the net result I believe will be that one will have fewer RF channels, and more 'sub-channels' on a particular RF channel.

 

Currently the US has 6 MHz channels for TV, as well as other NTSC countries, DVB-T has a range of 6-8 MHz. So potentially PAL/DVB-T lands could have higher bit rates, depending, but again will probably be squeezed for more subchannels.

 

Over The Top (OTT) content delivery I think is the area that will see 4K if it becomes popular, and perhaps would be part of a 'premium' package.

 

The Irony is... For most people who are accessing OTT content, they are doing so with mobile devices for which 4K, 2K, 720 are almost over kill, unless they have attached their mobile device to a larger display (which is how the Clark Family views TV content... never had cable... but I digress...).

 

To get an idea of the bit rates of content, at least for Youtube... if you 'right' click or 'control-click'(for macs), in the content window, you will get a menu, one of the items is "Nerd Stats"... click on that and you will get some stats on bit rate, buffering, etc, and depending on the 'pipe' you will see that many clips will pay reasonably well at bit rates of 1-2 Mbps... again given a 'mobile' device is being used. And in some cases even an ordinary laptop display, in full screen mode, may be about 3-4 Mbps for an 'acceptable' presentation.

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