Secondary video track (1080p) in some UHD movies

[Ghitulescu]

I do not have much experience with UHD, but I want to know what is the secondary track for?
I demuxed it and it displayed solid green, so it was not for PiP as I initially thought nor for menus.

Thanks

[Selur]

some normal blu-rays have dummy tracks which were just that dummy tracks as a way to confuse ripping software and similar,.. might be the same here,...

Are you sure that you are not just picking up a Dolby Vision layer? It reads as a 1080p stream alongside the UHD stream. If you try to play it on its own, it won't decode correctly and might well display as solid green.

[videoh]

Yes. Open the disk in DGDemuxGUI and select the desired MPLS. If the second video is DolbyVision it will be marked as such.

[FranceBB]

Originally Posted by Richard1485

Are you sure that you are not just picking up a Dolby Vision layer? It reads as a 1080p stream alongside the UHD stream. If you try to play it on its own, it won't decode correctly and might well display as solid green.

Yep. It's almost definitely a Dolby Vision layer.

@Ghitulescu if you see something like this:



It's Dolby Vision.
Basically there are two layer: the first one is a normal 3840x2160 10bit H.265 stream and the second one is just "data" which you see as 1920x1080 H.265 10bit but you can't decode separately otherwise it will be just green.

The idea is that:

A) If the decoder is Dolby Vision Aware, it will find the second layer and use it in conjunction with the first to create a 3840x2160 12bit HDR PQ stream to the TV.

B) If the decoder is NOT Dolby Vision Aware, it will ignore the second layer and play the first one as a simple HDR PQ 4:2:0 10bit 3840x2160 stream.

[Ghitulescu]

Thank you very much for all the answers.

Indeed, it was the Dolby Vision, as indicated in the DGDemuxGUI (by clicking upon any of the main movies' playlists).