Cropping HDR input with HDR10, HDR10+ and Dolby Vision

[zweifingerjoe]

Hi, does somebody know when you can crop away the black bars on a hdr source and when not?
I already know that one can crop hdr10 and reuse the mastering display metadata on the cropped encode. But what about MaxCLL and MaxFALL? Do they have an "active area" or do they refer the light levels of the whole frames including black bars?
I made a list with what I know and what I don't know. I want to complete that information for every HDR standard that is relevant today:

HDR10

Mastering display metadata can be reused on a cropped reencode
MaxCLL and MaxFALL unknown


HDR10+

Unknown


Dolby Vision

Dolby Vision Metadata has an "active area" defined, if that area excludes the black bars, it can be redefined for a cropped reencode, then the metadata can be reused

[benwaggoner]

Hi, does somebody know when you can crop away the black bars on a hdr source and when not?
I already know that one can crop hdr10 and reuse the mastering display metadata on the cropped encode. But what about MaxCLL and MaxFALL? Do they have an "active area" or do they refer the light levels of the whole frames including black bars?
I made a list with what I know and what I don't know. I want to complete that information for every HDR standard that is relevant today:

HDR10

Mastering display metadata can be reused on a cropped reencode
MaxCLL and MaxFALL unknown


HDR10+

Unknown


Dolby Vision

Dolby Vision Metadata has an "active area" defined, if that area excludes the black bars, it can be redefined for a cropped reencode, then the metadata can be reused

The metadata is supposed to exclude everything out of the active image area. I don't trust that all implementations do that correctly in default configurations, as what is "active image area" can be very challenging to determine without a whole-title analysis. Plenty of content may change aspect ratio an hour in, for example.

[zweifingerjoe]

Thank you very much for your answer,
so that means that MaxCLL and MaxFALL could be reused with a cropped reencode and it should work.

What about hdr10+, it is the same there?

[benwaggoner]

Thank you very much for your answer,
so that means that MaxCLL and MaxFALL could be reused with a cropped reencode and it should work.
Correct. And thank goodness!

What about hdr10+, it is the same there?
I am almost certain it is, but don't have the spec in front of me.