UHD BD to BD?

[Chewtobacca]

Pretty sure your not able to do that yet with mkv, it shows up as 1920 x 1080. Plus all the mkvs i've seen that have DV on the BD never have DV muxed with it. Unless MKV was updated recently and it now supports it but i don't think it does. If i'm wrong then great.

I don't think you are wrong, just that it's possible to put that layer in an MKV and that some people are doing so in the probably misguided hope that support for it will appear at some point. The 1080p thing is just an irrelevant field; the layer doesn't really have a resolution in that sense.

EDIT: The 1080p thing's causing plenty of confusion though.

[DoomBot]

I see what your saying but what if down the road they add support and now it doesn't read it correctly because mkv doesn't really know what to do with it right now. I would just keep the untouched m2ts file around instead. Anyways, that's a whole other issue all together.

[Chewtobacca]

Playback issues with the MKV are certainly possible, though I've just watched one such remux without incident. The reason for not keeping the video in the M2TS is that I can't make MPC play a UHD BD playlist, and this is a branching title.

[zoidberg]

Interesting to hear that Dolby Vision contains SDR metadata within it's metadata (metametadata?). Is this something only hardware can decode?

[Synnove]

From an article concerning the SDR meta data in Dolby Vision:

"The Dolby Vision process analyzes the HDR grade (in the grading software) and the Dolby Content Mapping Unit (CMU) takes the metadata produced by the analysis process (embedded over SDI) and in real-time creates a Standard Dynamic Range (SDR) version of the project (the smaller end of the funnel).

Unlike HDR10 (another HDR standard) where mapping from HDR to SDR is passive and applied over the entirety of the program, Dolby Vision allows for frame by frame or shot by shot SDR mapping. Meaning that the colorist, DP and director can provide creative input to how the SDR version of the project is derived by use of ‘trim’ controls within the grading software while targeting a chosen SDR display spec (usually 100-nit gamma 2.4).

Trims can happen on a frame by frame or shot by shot basis so that that the SDR version of the project matches as closely as possible to the original intent of the HDR grade."

Basically, the difference between a regular HDR10 grade and a Dolby Vision grade, is that the DV grade includes an extra step where the colorist specifies how to transform the HDR content to SDR... this is exported as metadata.

In regards to the 1080p DV layer:

[X5gb]

It would be nice to now if ripbot is using both but unfortunately the developer is appearing to ignore questions on the Videoredo forum regarding what process is used by the app to do tonemapping.

[zoidberg]

Looking through ripbot's plugins it looks like it's using something called DGTonemap. It's an avisynth+ plugin

[CSchmidlapp]

Looking through ripbot's plugins it looks like it's using something called DGTonemap. It's an avisynth+ plugin

A simple Avisynth+ script that does a the UHD to BD conversion would be great.
Im currently still in 32bit land in this regard due to some horrible bugs! So no 10bit outside of the ffmpeg hack for me at the moment

[zoidberg]

Ffmpeg can convert HDR->SDR as well

[Chewtobacca]

Interesting to hear that Dolby Vision contains SDR metadata within it's metadata (metametadata?). Is this something only hardware can decode?

I've not read of any software that can do it. Were you thinking that it might be possible to cap the SDR grade that a DV-compliant player puts out?