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Discussion - HDR movies mastered at diff nits VS calibration


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I read this discussion online where they discussed about whether separate calibrations are required for HDR movies mastered at different nits.

 

Interesting point is, they mentioned every movie is mastered at different nits, and also each brand/model displays' tone mapping is all different. Making it complicated.  See a post by one of the experienced display gurus:

"each display is doing different tone mapping according to the movie metadata, some displays don't do anything, some are roll-off sooner when they will see 4000nits (like 2017 LG OLED's), others don't do anything (like 2016 LG OLED's....if you send 1000 or 4000), others like Panasonic EZ1000 is counting MaxCLL also, but not all values; it's ignoring any MaxCLL below 401nits and above about 5000 nits. If you pause a frame and send different MaxCLL with HD Fury, the picture will change, it can be measured also what its doing by taking greayscale sweep.

 

For these reasons with HDR10 and static metadata, because there no golden standard about what tone/gamut mapping the HDR10 displays will perform with each movie incoming metadata, it's up to display model/brand/firmware that strategy will follow (clip/soft roll-off etc)"

 

 

Point for discussion/ views: Are separate calibrations required for HDR movies that are mastered at different nits?

https://www.avsforum.com/forum/139-display-calibration/2955214-uhd-media-mastered-1000-nits-vs-4000-nits.html

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I read this discussion online where they discussed about whether separate calibrations are required for HDR movies mastered at different nits.

 

Interesting point is, they mentioned every movie is mastered at different nits, and also each brand/model displays' tone mapping is all different. Making it complicated.  See a post by one of the experienced display gurus:

"each display is doing different tone mapping according to the movie metadata, some displays don't do anything, some are roll-off sooner when they will see 4000nits (like 2017 LG OLED's), others don't do anything (like 2016 LG OLED's....if you send 1000 or 4000), others like Panasonic EZ1000 is counting MaxCLL also, but not all values; it's ignoring any MaxCLL below 401nits and above about 5000 nits. If you pause a frame and send different MaxCLL with HD Fury, the picture will change, it can be measured also what its doing by taking greayscale sweep.

 

For these reasons with HDR10 and static metadata, because there no golden standard about what tone/gamut mapping the HDR10 displays will perform with each movie incoming metadata, it's up to display model/brand/firmware that strategy will follow (clip/soft roll-off etc)"

 

 

Point for discussion/ views: Are separate calibrations required for HDR movies that are mastered at different nits?

https://www.avsforum.com/forum/139-display-calibration/2955214-uhd-media-mastered-1000-nits-vs-4000-nits.html

 

This is very true...unfortunately there is no "one-size-fits-all" calibration here. The problem with HDR right now is the use of "static" meta data (MaxCLL and MaxFALL) which in itself can be the bottleneck since no one disc or display is able to reproduce faithfully what the studio-mastered disc wanted (e.g. a movie authored in 4,000 nits but the display can only reproduce 1,000 nits max). That's where tone-mapping comes in but the use of static meta data is what limits the latent potential of HDR right now...this is what creates all the disappointments...

 

Panasonic UB9000/820 is the closest solution for static meta data as it only tone map on the highlights and preserve most of the dark and shadow details. For projector users, at least for JVC N series projectors is to create 2 separate custom tone curves - one for 1,000-4,000 nits and the other one for 500 - 300 nits.

 

The way moving forward for HDR is to be able to analyze the meta data "dynamically" either by the display (HTPC or TV) or source (4K UHD player, media player or HTPC using MadVR).

 

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For projector users, at least for JVC N series projectors is to create 2 separate custom tone curves - one for 1,000-4,000 nits and the other one for 500 - 300 nits.

 

 

Thanks desray. So good that the JVC projector  can allow 2 custom tone curves.

 

Dont mind, for learning, what would "happen" to the image if we watch a HDR movie mastered at 4000 nits with a HDR display that can output max 500 nits peak luminance in the below scenarios:

 

1) display device do not allow any custom tone curve; and

 

2) use a custom tone curve for 4000 nits?

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Thanks desray. So good that the JVC projector  can allow 2 custom tone curves.

 

Dont mind, for learning, what would "happen" to the image if we watch a HDR movie mastered at 4000 nits with a HDR display that can output max 500 nits peak luminance in the below scenarios:

 

1) display device do not allow any custom tone curve; and

 

2) use a custom tone curve for 4000 nits?

 

Actually that’s one question by itself. Expect clipping since there is no tone mapping (meaning doesn’t deploy any custom tone curve). The maximum is till 500 nits so you can’t go past that threshold. Picture wise, you can still get very good punchy and plenty bright. What you lose out is retaining the speculate highlights (since clipping will occur). If display is exactly the same as the content source mastered at 4,000 nits, then no tone mapping required. It will be not “nit for nit” (1:1) presentation BUT there is no display that can do 4,000 nits not even 1,000 nits at a constant rate. Unless you have some kind of studio master display to play around but that’s not meant for consumers to begin with.

 

 

Sent from my iPhone using Tapatalk

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thanks for sharing bro. Helps a lot

 

Understand, so lose out speculaliar highlights on the "speculiar" areas in the image.

 

Theoretically, the shadow details in that image should still remain right? Or does it still depend on how the brand/TV tone mapping approach is?

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thanks for sharing bro. Helps a lot

 

Understand, so lose out speculaliar highlights on the "speculiar" areas in the image.

 

Theoretically, the shadow details in that image should still remain right? Or does it still depend on how the brand/TV tone mapping approach is?

 

 

Not necessary for the low end...it depends as if the display has tone-mapping...the overall PQ will be dimmed so as to tone map (compression occurs) to fit the 500 nits. As long as the PQ becomes dimmed...human eyes will be quite sensitive the overall brightness just like we did for colors. You may find find the blacks unsatisfying IF the display has a limitation in showcasing the blacks as black floor may be raised which makes the dark crushed or with a greyish tone. In short, as long as tone map comes in, it is up to the display capability to showcase the best of HDR content and different brands of OLED TV or even projector takes a different approach in doing tone-mapping as such YMMV.

 

Having say that, Panasonic UB9000/820/420 using the HDR Optimiser is a different implementation as Panny's HDR algorithm is "smart" enough to retain the black levels and shadow details while preserving the specular highlights w/o sacrificing the overall brightness. So in a way, many AV enthusiasts have touted the Pannies as the "best" companion player for playback of HDR.

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thanks for the heads up on the DVD bit bro!

 

Is it confined to just the UB820? Or is the UB820 is region free?

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The carousell page not ub820 lah... so don't get too excited!

 

yea i know. that one 420.

 

But im just wondering if the 820 is region free for DVD =)

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