HDR Discussion Thread

[ray0414]

Originally Posted by zmarty

Here's the explanation I added to the video: "When Netflix Meridian was released under a Creative Commons license there were several articles in the press about it, seemingly citing from the same press release. All the articles mentioned that the video was released in HDR, and therefore Rec2020 color space. Working with this assumption we uploaded a version of Netflix Meridian where the colors had issues; for instance the skin tones looked very orange. After feedback from users on this channel and after analyzing the footage we have concluded that the video Netflix released is not in fact in Rec2020 color space, but more likely in Rec709. So this new version starts from this assumption. We hope you will agree that the results look much better. We hope Netflix will one day release the actual master file promised in the press, not a neutered version."

More questions and comments regarding Meridian.


I ju st watched the Netflix version and your new version. And I must say, your version on youtube to me is superior. It has better pop to the picture. But most notably, its a cleaner image. Netflix version is grainy, like most of their 4k content. Any idea why netflix's content is so grainy? It's a common complaint among alot of people. Idk if they are using inferior compression or what.

[zmarty]

Originally Posted by ray0414

I just watched the Netflix version and your new version. And I must say, your version on youtube to me is superior. It has better pop to the picture. But most notably, its a cleaner image. Netflix version is grainy, like most of their 4k content. Any idea why netflix's content is so grainy? It's a common complaint among alot of people. Idk if they are using inferior compression or what.

Quite interesting. I don't know if I can answer your question fully, but here's some more information about it:
- Meridian is also supposedly available in Dolby Atmos, but I suspect the file they published does not have it.
- Meridian has two versions on Netflix: HDR and SDR. If I remember correctly the HDR one is in Dolby Vision. On my LG OLED there is a distinct difference between the color grading of the HDR and SDR versions. The HDR version has much flatter colors, while the SDR version is more yellow.
- Interestingly, when YouTube took my HDR version and converted it to SDR (for SDR screens), they managed to somehow get the same difference (more yellow / saturation in the SDR version).
- Last time I checked with my router Netflix 4K is about 15 Mbps (they recommend 25 Mbps just to ensure a stable buffer). But the bitrate for Meridian is probably higher, since it's both HDR and 60 fps. So it's more close to 20-25 Mbps.
- The version I uploaded to YouTube is 30.2 GB (336.5 Mbps), compressed from my master file of 146 GB (which was 1.7 Gbps!).
- YouTube recommends the upload bitrate of high frame rate content (50-60fps) should be 66-85 Mbps.
- I don't know what bitrate YouTube uses to serve this video, but it may be, as you suggested, higher than what Netflix can do.

[ray0414]

Originally Posted by zmarty

Quite interesting. I don't know if I can answer your question fully, but here's some more information about it:
- Meridian is also supposedly available in Dolby Atmos, but I suspect the file they published does not have it.
- Meridian has two versions on Netflix: HDR and SDR. If I remember correctly the HDR one is in Dolby Vision. On my LG OLED there is a distinct difference between the color grading of the HDR and SDR versions. The HDR version has much flatter colors, while the SDR version is more yellow.
- Interestingly, when YouTube took my HDR version and converted it to SDR (for SDR screens), they managed to somehow get the same difference (more yellow / saturation in the SDR version).
- Last time I checked with my router Netflix 4K is about 15 Mbps (they recommend 25 Mbps just to ensure a stable buffer). But the bitrate for Meridian is probably higher, since it's both HDR and 60 fps. So it's more close to 20-25 Mbps.
- The version I uploaded to YouTube is 30.2 GB (336.5 Mbps), compressed from my master file of 146 GB (which was 1.7 Gbps!).
- YouTube recommends the upload bitrate of high frame rate content (50-60fps) should be 66-85 Mbps.
- I don't know what bitrate YouTube uses to serve this video, but it may be, as you suggested, higher than what Netflix can do.

It definitely plays in hdr10 with Netflix on my ks9800, but as you noted, its not very saturated. Your though has excellent saturation giving the picture more pop and depth.

Will lack of bitrate cause noise in the picture?

[zmarty]

Originally Posted by ray0414

It definitely plays in hdr10 with Netflix on my ks9800, but as you noted, its not very saturated. Your though has excellent saturation giving the picture more pop and depth.

Will lack of bitrate cause noise in the picture?

Well, as you may have guessed based on my previous description, my HDR version is derived from their SDR version. I would not normally do that, but thankfully their master file has at least 10 bit color and very high bitrate, so that allows color grading on it just fine.

So the saturation is because of me. But the difference in grain is not, not sure what's going on there. But yes, the difference in bitrate can cause noise.

[ray0414]

Originally Posted by zmarty

Well, as you may have guessed based on my previous description, my HDR version is derived from their SDR version. I would not normally do that, but thankfully their master file has at least 10 bit color and very high bitrate, so that allows color grading on it just fine.

So the saturation is because of me. But the difference in grain is not, not sure what's going on there. But yes, the difference in bitrate can cause noise.

Interesting stuff.

Curious too if the grain differences is because of HEVC on Netflix and VP9 on youtube?


Edit: apparently netflix uses h264? So they done even use HEVC??



http://variety.com/2016/digital/news...p9-1201932502/

[zmarty]

Originally Posted by ray0414

Curious too if the grain differences is because of HEVC on Netflix and VP9 on youtube? Edit: apparently netflix uses h264? So they done even use HEVC??

Oh, another interesting topic. YouTube does not accept H.265/HEVC uploads and also does not serve content with this codec.

From what I figured out from talking to YouTube engineers (and more specifically what they refused to answer about), my best guess is that this is a licensing feud.

When I upload an HDR video I can either do that in H.264 with 10 bit color, or in DNxHR HQX (which is 12 bit) for even higher quality. Both of these codecs are quite reasonable in terms of licensing.

When they transcode the video they seem to generate H.264 and VP9 files. VP9 is obviously their answer to H.265, but it is still a PITA that they do not support HEVC.

[ray0414]

Originally Posted by zmarty

Oh, another interesting topic. YouTube does not accept H.265/HEVC uploads and also does not serve content with this codec.

From what I figured out from talking to YouTube engineers (and more specifically what they refused to answer about), my best guess is that this is a licensing feud.

When I upload an HDR video I can either do that in H.264 with 10 bit color, or in DNxHR HQX (which is 12 bit) for even higher quality. Both of these codecs are quite reasonable in terms of licensing.

When they transcode the video they seem to generate H.264 and VP9 files. VP9 is obviously their answer to H.265, but it is still a PITA that they do not support HEVC.

I wonder if that's why youtube content generally is pounded with compression bands and blocks. Their hdr content is nearly flawless because of VP9, but everything else is messy on my tv.

[Penton-Man]

Originally Posted by zmarty

Mr. Penton-Man, I dedicate this video to you.

I have published what I believe to be the first HDR technical analysis / review ... in HDR. You need YouTube HDR to view it properly, but the analysis itself should be useful even when viewing on an SDR screen.

In the video I am trying to provide some general information about HDR, and to determine if the Star Trek Beyond 4K Blu-Ray is as dark as some reviews complained. See the description below the video for more information.

Real 4K HDR: Star Trek Beyond HDR Review and general HDR information (Chromecast Ultra) - YouTube

Thank you. That truly is a nice gesture.

It’s kind of ironic how some home theater enthusiasts all across the web have objected to the ITU’s 5 nit surround lighting recommendation for production, when for years, said enthusiasts have vigorously gone on to chastise others on AV forums for not viewing their movies in what they've considered/promoted as a proper dark or near dark environment.

[DanBa]

Originally Posted by Penton-Man

...
You can do it with an ~1,000 nit Sony BVM X-300 (even a lesser bright Canon DP-V2410)....a Dolby CMU (you can get here... http://www.nmh.com/ ), a Dolby Vision supported color corrector (Baselight, Lustre, Resolve, etc.) and of course, paying for a Dolby Vision mastering and playback license to allow the later to engage. In general, depending on the color corrector and version, you're given several SMPTE ST 2084 peak luminance setting options, e.g. 300 nits, 500 nits, 800 nits, 1000 nits, 2000 nits and 4000 nits.
...

"To illustrate the Hunt effect, Poynton suggested we think of the color of flowers in sunlight, then think of the color of those same flowers at twilight. The color of the flowers has not changed, but our perception of the colorfulness of them has – they don’t look as colorful in dim light. His point: “If you capture the flowers in daylight and show on a display with only 300 nits of brightness, the flowers will look like they are captured at twilight.” Since displays cannot show the full dynamic range of the natural world, we have to apply “artistic intent” to alter the image to produce what is desired. In other words, if you want the flowers rendered at 300 nits to have the visual colorfulness that they did in sunlight, you have to add more color. It is not accurate, but it conveys the artistic intent."
http://www.insightmedia.info/a-day-w...arles-poynton/

In order to preserve the artistic intent, i.e. to have the visual colorfulness that these flowers did in sunlight, I am wondering if the colors of these flowers should be modified for each target display: 300 nits, 500 nits, 800 nits, 1000 nits, 2000 nits, 4000 nits.

[Penton-Man]

^ Dan, vis-à-vis thru the CMU, Dolby provides an automatic conversion for that and if the colorist isn’t completely satisfied with the look, he/see can always trim it, manually with the color correction controls.

[Penton-Man]

Originally Posted by zmarty

We hope Netflix will one day release the actual master file...

zmarty, need assistance ? on Meridian -





reaching out to Andrey Norkin at Netflix may help, as he’s quite familiar with it.

[Penton-Man]

One of the more interesting scenes in Meridian to evaluate…..

[DanBa]

Originally Posted by Penton-Man

^ Dan, vis-à-vis thru the CMU, Dolby provides an automatic conversion for that and if the colorist isn’t completely satisfied with the look, he/see can always trim it, manually with the color correction controls.

As there is only one master HDR video track and N metadata tracks, I am wondering what is the color correction display adaptation instruction / metadata for each target display.

[zmarty]

Originally Posted by Penton-Man

reaching out to Andrey Norkin at Netflix may help, as he’s quite familiar with it.

Thanks, I contacted him. Where did you get the details about the clip? Does it say anything about audio (the video has the Dolby Atmos logo in the credits)? How about HDR (both Dolby Vision and HDR10)?

[Robert Zohn]

I'll be speaking at the NAB Convention in April about HDR. Anyone attending NAB?

Here's a brief overview of my presentation listing. If anyone's interested I can post an outline of my presentation.

[zmarty]

Originally Posted by zmarty

Thanks, I contacted him. Where did you get the details about the clip? Does it say anything about audio (the video has the Dolby Atmos logo in the credits)? How about HDR (both Dolby Vision and HDR10)?

To close on the Netflix Meridian issue, Andrey confirmed the version published by Netflix is Rec709. They plan to release a P3 4000 nits version of it as soon as Mozilla upgrades their hosting infrastructure (for xiph.org).

Mr. Penton-Man, thanks again about the connection.

[Penton-Man]

Originally Posted by zmarty

Thanks, I contacted him. Where did you get the details about the clip? Does it say anything about audio....

It’s a candidate as a test sequence in standards work wrt video compression -
https://www.itu.int/CookieAuth.dll?G...on=0&formdir=7

Sorry, I don’t know anything about the audio.

[Penton-Man]

Originally Posted by Robert Zohn

I'll be speaking at the NAB Convention in April about HDR. Anyone attending NAB?

It takes money to go to all these shows. I plan to, but it may ultimately be determined by how my retirement account is faring if they try to kill the Fiduciary Rule….
http://time.com/money/4659440/fiduci...-donald-trump/

I had been counting on being able to trust my financial advisor without reservation.

Originally Posted by Robert Zohn

...If anyone's interested I can post an outline of my presentation.

Go for it.

[Penton-Man]

Originally Posted by zmarty

To close on the Netflix Meridian issue, Andrey confirmed the version published by Netflix is Rec709. They plan to release a P3 4000 nits version of it as soon as Mozilla upgrades their hosting infrastructure (for xiph.org).

Mr. Penton-Man, thanks again about the connection.

You're welcome.

[ray0414]

Originally Posted by zmarty

To close on the Netflix Meridian issue, Andrey confirmed the version published by Netflix is Rec709. They plan to release a P3 4000 nits version of it as soon as Mozilla upgrades their hosting infrastructure (for xiph.org).

Mr. Penton-Man, thanks again about the connection.

I wonder if the new version will replace the old version or just be an addition? There's currently 2 versions to click on but I'm not sure if they are different.