Dolby Vision now possible through MP4 Mux.

[danbez]

@quietvoid and @RESET_9999 is this FEL expansion issue more of a problem for >1000-nit displays or is it also a problem on typical 700-1000-nit OLEDs?
Also, is there anywhere where one of you (or someone else) has completely explained why this FEL expansion issue exists and what is happening in detail?
Is it better to just watch in HDR instead of DV for movies with FEL expansion if a FEL compatible player isn't an option?

it's a problem for any display.
The TV receives brightness metadata (L1/L2) that is wrong for the content it's displaying so because it thinks the content is much brighter than it is, it dims the brightness accordingly to adapt to its capabilities.

see:
https://www.youtube.com/watch?v=nT1qBQLZIIc
https://www.youtube.com/watch?v=S0J0blslHjY
https://www.youtube.com/watch?v=VObky4peBXE

On top of that, we also have titles where the Base Layer was poorly authored resulting in a lot of compression artifacts and other issues that are only fixed with the FEL layer. Typical examples are Total Recall, Halloween 2 and a few others.

[speeddemon]

The TV receives brightness metadata (L1/L2) that is wrong for the content it's displaying so because it thinks the content is much brighter than it is, it dims the brightness accordingly to adapt to its capabilities.

Do you/we have any idea why they're doing this?
Is it better to just watch in HDR instead of DV for movies with FEL expansion if a FEL compatible player isn't an option?
Would it be possible to re-write the L1/L2 metadata so it's corrected/"unexpanded"?

[RESET_9999]

Do you/we have any idea why they're doing this?
Is it better to just watch in HDR instead of DV for movies with FEL expansion if a FEL compatible player isn't an option?
Would it be possible to re-write the L1/L2 metadata so it's corrected/"unexpanded"?

4 options:
1- just watch in HDR10
2- bake the EL into the BL
3- generate a proper RPU in resolve for the BL actual brightness.
4- get a proper player

Expanding the brightness makes sense actually. It futureproofs the grade for when the TV will be brighter and it makes the content accurate on more type(brightness, HDR format) of display.

Because this way, people with brighter DV TV(G3) can enjoy brighter HDR and people with low nits DV TV can also get an accurate picture thanks to the trim pass and L1.
Then, people with HDR10-only TVs (low nits) can also get an accurate image with the 1000nits BL. If the BL was as bright as the EL, then those low-nits HDR10 TVs would look bad/clipped.

On top of that, we also have titles where the Base Layer was poorly authored resulting in a lot of compression artifacts and other issues that are only fixed with the FEL layer. Typical examples are Total Recall, Halloween 2 and a few others.

That's right. I found a couple that improve grain/details: https://docs.google.com/spreadsheets/d/ ... =917134052

[speeddemon]

3- generate a proper RPU in resolve for the BL actual brightness.

Do you have a tutorial for this or know of a tutorial for this?

Thanks!

[RESET_9999]

Do you have a tutorial for this or know of a tutorial for this?
Thanks!

https://www.youtube.com/watch?v=ZdFiqATo_j8

[speeddemon]

Do you have a tutorial for this or know of a tutorial for this?
Thanks!

https://www.youtube.com/watch?v=ZdFiqATo_j8

Can I do this in the free version of Resolve?

[RESET_9999]

Can I do this in the free version of Resolve?

I don't think so

[Trees]

And any reencoding of a Blu-ray into IPT would be worse as transcoding is lossy.

Of course. But visually lossless quality transcoding is possible. If it's advantageous to visually losslessly convert Blu-ray remuxes to IPTPQc2, why wouldn't you? We're all trying to get the absolute best quality available, after all.

What HDR would you say is the best, purely in terms of colour representation, accuracy and quality? P5, P7 or P8.1? Why is the IPTPQc2 colour space better than the YCbCr color space found on Blu-rays?

Sorry for all the questions, I'm just quite interested in the subject and trying to do a bit of research in Dolby Vision (I've tried to read the white papers, but they're too overwhelming). I'm just trying to find out what is best for me, in layman's terms. I leaning towards valuing HDR quality over bit rate, so I'm willing to trade in my remuxes for WEB-DLs, they're very good these days, but only IF the HDR is actually better than the HDR found on Blu-rays.

[quietvoid]

Of course. But visually lossless quality transcoding is possible. If it's advantageous to visually losslessly convert Blu-ray remuxes to IPTPQc2, why wouldn't you? We're all trying to get the absolute best quality available, after all.

Because it doesn't make a difference, if it's lossless then your output looks the same. Regardless of the final colourspace.

What HDR would you say is the best, purely in terms of colour representation, accuracy and quality? P5, P7 or P8.1? Why is the IPTPQc2 colour space better than the YCbCr color space found on Blu-rays?

Bitrate usually trumps anything else, but YMMV.

[speeddemon]

Can I do this in the free version of Resolve?

I don't think so

I have Resolve Studio on my work computer and am going to give this a try later today.

Is the FEL Expansion more significant on some movies compared to others? I can't see the difference when toggling between watching "The Super Mario Bros. (2023)" with FEL stripped and with FEL enabled. I also can barely see a difference when toggling here: https://slow.pics/c/WAdUe5GZ

Do you know whether this kind of expansion also happens on Profile 5 IPTPQc2 videos?
I'm looking at the L1 plot for "The Super Mario Bros. (2023)" and can't tell how you'd determine this:


Compared to the Profile 7 FEL plot:

[RESET_9999]

Do you know whether this kind of expansion also happens on Profile 5 IPTPQc2 videos?

only fel can expand brightness. Well the L2 trim passes too can make it brighter but it has nothing to do with fel.
The studios sometimes deliver different version for streaming and disc... It was the same for Rise of gru. The WEB version is 2000nits but the bluray BL is 1000nits with fel that restore the original HDR master.

Is the FEL Expansion more significant on some movies compared to others?

yes, and sometimes it's just the highlights that are brighter. https://slow.pics/c/pzYlva2Y
Any difference from the HDR master is recorded in the EL.

[RESET_9999]

Of course. But visually lossless quality transcoding is possible. If it's advantageous to visually losslessly convert Blu-ray remuxes to IPTPQc2, why wouldn't you?

IPTPQc2 is better when it's encoded straight from the 12bit master. The colorspace is more efficient and retains more color information which in the end is the equivalent of 11.5bits YCbCr(exceeding our tv capabilities btw).
There's no point/benefit in going from 10bit YUV to IPTPQc2.

[spl147]

Do you/we have any idea why they're doing this?
Is it better to just watch in HDR instead of DV for movies with FEL expansion if a FEL compatible player isn't an option?
Would it be possible to re-write the L1/L2 metadata so it's corrected/"unexpanded"?

4 options:
1- just watch in HDR10
2- bake the EL into the BL
3- generate a proper RPU in resolve for the BL actual brightness.
4- get a proper player

Expanding the brightness makes sense actually. It futureproofs the grade for when the TV will be brighter and it makes the content accurate on more type(brightness, HDR format) of display.

Because this way, people with brighter DV TV(G3) can enjoy brighter HDR and people with low nits DV TV can also get an accurate picture thanks to the trim pass and L1.
Then, people with HDR10-only TVs (low nits) can also get an accurate image with the 1000nits BL. If the BL was as bright as the EL, then those low-nits HDR10 TVs would look bad/clipped.

On top of that, we also have titles where the Base Layer was poorly authored resulting in a lot of compression artifacts and other issues that are only fixed with the FEL layer. Typical examples are Total Recall, Halloween 2 and a few others.

That's right. I found a couple that improve grain/details: https://docs.google.com/spreadsheets/d/ ... =917134052

How would i bake the EL into the BL?

This is for FEL titles only correct?

[speeddemon]

3- generate a proper RPU in resolve for the BL actual brightness.

Do you have a tutorial for this or know of a tutorial for this?

https://www.youtube.com/watch?v=ZdFiqATo_j8

Aside from the time/effort involved. Is there a downside to doing this and/or anything you miss out on or that could be improved upon further from your tutorial?
Also, what would it take to analyze for multiple trims or does it already do this? Have you ever attempted this?

Also, I followed the guide and generated this for The Super Mario Bros (2023):


Does this look correct?

Here's the DoVi XML and HDR10+ JSON as well.

Also, thank you RESET_9999 for putting together these tutorials and scripts!

[RESET_9999]

How would i bake the EL into the BL?

This is for FEL titles only correct?

https://github.com/erazortt/DoViBaker

also, the latest version of my script can encode P7 FEL to P8.. Workflow (6-9)

Aside from the time/effort involved. Is there a downside to doing this and/or anything you miss out on or that could be improved upon further from your tutorial?

The only thing I don't do in the video is the project image scaling. I found out that if you set your project to 1080p with cubic algo, it produces much better metadata that are almost identical to the original.
https://ibb.co/r2tMX6n

Also, what would it take to analyze for multiple trims or does it already do this? Have you ever attempted this?

Your project set to CMV4.0 will produce L2 trims. My script by default, will remove them as explained recently in this thread.