Vero 4K KODI not passing (some) HDR metadata

I don’t think so. I think the differences between how studios and directors are making use of the bigger gamut/dynamic range are greater than the difference between material with MaxFALL/CLL and without.

Has anybody done a study on whether this metadata makes any difference to the picture quality?
I’ve just run mediainfo on a random 8 UHD files in my collection and only 2 had the MaxFALL/CLL info and a quick google seems to suggest it is not mandatory information for decoding, only during mastering.

I don’t design TVs, but if I did, what would I do with MaxFALL? If it was higher than my panel could manage, would I dim the whole movie just so those few seconds would play ‘in proportion’? No - I would limit the overall level just for those few seconds, attempting to make it as unobtrusive as possible. Just the same as I would do for a movie without MaxFALL.

As for MaxCLL, I guess if it was a lot less than the maximum brightness of the mastering display I could think about adjusting the tonecurves to better suit the range of my display. But I wouldn’t mess with the mid-tones or darks.

Bottom line: I doubt very much if you would see any difference.

From what I’ve read most consumer displays take no notice of the metadata anyway, other than the new JVC projector’s Auto Tone Mapping feature.
As it seems a lot of UHD material has the metadata either missing or “best guessed” based on the properties of the equipment used during the HDR grading process I wonder how useful that feature actually is?

There is some interesting (depending on your point of view :smile: ) info on MaxFALL/CLL here:
https://www.streamingmedia.com/Articles/ReadArticle.aspx?ArticleID=118846&PageNum=2
https://www.mysterybox.us/blog/2016/10/19/hdr-video-part-3-hdr-video-terms-explained
https://www.mysterybox.us/blog/2016/10/27/hdr-video-part-5-grading-mastering-and-delivering-hdr

That Mysterybox series is a good read. Strips away the BS.

This is why I am personally so interested in the HDR metadata being passed by OSMC. I am running a JVC RS2000. The Auto Tone Mapping feature makes a significant difference when it is passed a source that has proper metadata, since projectors are not generally able to display the full range of HDR brightness. Otherwise the user needs to tweak the gamma levels themselves per movie. I have had excellent results with the Auto Tone Mapping on sources that provide proper metadata.

For the record, of course there are many UHD titles that don’t provide any metadata, and there’s nothing that can be done there, but the ones that do should be supported.

@sam_nazarko Any updates to HDR metadata in the recent releases?

Yes I’m hoping this will be added soon.

It will come with the 4.9 kernel.

Will this be the next release (August update)? Or is that still unclear and depending on testing?

Not necessarily.

It will be released when it is ready.

4 Likes

Could you explain to a noob why a kernel change is necessary to make playback improvement? From a noob perspective it’s kodi that Does this things and osmc is just a platform that kodi runs on.

This is a fair explanation…

1 Like

It’s not necessary, but it no longer makes sense to add these improvements to the current kernel.

2 Likes

So I too have been struggling with calibrating HDR on my Q9FN and just realised that the Vero does not pass MaxCLL etc.

When will this be fixed please?

It should work when we upgrade to 4.x kernel, which Sam has targetted for ‘end of summer’.

1 Like

@grahamh,

what will this new kernel "bring"us, I’m not interested in when, I’m sure it will come as you (OSMC) are developing it ;-), but more what for extra’s this kernel can give.

Maybe it’s already somewhere on this forum being described, but maybe i’m mixing things, I’ve read something about Kodi and AMlogic “removal” as is being told for kodi 19.

The obvious things you will get are HLG and this UHD metadata thing. And I guess more peripheral devices should work out-of-the-box ie without a huge backporting exercise.

AMLogic ‘removal’ from Kodi is a different matter. We have a strategy for that.

Thanks for your quick reply, I’ll looking forward to them :slight_smile:

Just to illustrate the importance of this metadata, I have attached snaps of HDR 2k nits clipping pattern for Vero vs Samsung Internal player.

The Vero (incorrectly) clips at 1k (75%) while the Sammy (correctly) clips at just under 2K nits (81%).

1 Like