[ac16161]

The recently released UHD's of the Godfather films have numerous scenes with forced subtitles. When played from disc the subtitles are a yellow/gold colour. When played via Kodi 19.4 on a Vero, they are grey (file source is direct from makemkv). Have posted this on the OSMC forum and have been advised it looks like a cross-platform issue so am posting here. Not sure if this log will help, playback of a scene early in Part II with forced subs active. I've noticed grey subs before with HDR sources but they jump out on the Godfather titles as the UHD's, like the bluray versions, have yellow subs via disc.

https://paste.osmc.tv/ubavusizir

[Karellen]

When played from disc the subtitles are a yellow/gold colour. When played via Kodi 19.4 on a Vero, they are grey

What happens when you play in another player, like VLC or similar? What colour are they? I am wondering if the ripping process has altered the colour of the images.

The subtitles in your rip are pgs, which are images of text. I am not aware of Kodi being able to change the colour of images.

Maybe @CastagnaIT might have a better idea.

xml:
DEBUG <general>: ffmpeg[0xb05e54b0X]: [matroska,webm] Could not find codec parameters for stream 2 (Subtitle: hdmv_pgs_subtitle (pgssub)): unspecified size

DEBUG <general>: ffmpeg[0xb05e54b0X]: [matroska,webm] Consider increasing the value for the 'analyzeduration' and 'probesize' options

[CastagnaIT]

as you answered its right, FWIK the subs images are preserved without any changes

i have not well understand the two sources
-disc -> yellow subs, is this HDR?
-mkv -> always gray subs? is this still HDR? or has been converted to SDR?

I know that subtitles are affected by the Kodi HDR video conversion
could be something wrong in HDR to SDR conversion?
or a possible problem in the video rendering (in this case not my area) but here i think could depends also on OSMC changes?

do you have a chance to test by installing the official Kodi version on a computer? if you can also with Kodi 20?

[ac16161]

Thanks for the comments. Replies as follows:

• disc playback is via a full HDR10 chain and the forced subs from UHD disc are similar yellow/gold colour to the blu-ray disc (Panasonic UB420 > Marantz NR1711 > Panasonic 55HZ980)
  
• UHD mkv file sourced from makemkv 1.16.7, only post-processing is to use the header editor in mkvtoolnix to set the forced flag for the relevant sub track
  
• HDR10 mkv playback from Vero > Marantz > Panny OLED has grey subtitles, but otherwise match the disc in terms of font and shadow effect
  
• mkv playback of HDR source via Kodi 19.4 and latest v20 nightly on Windows 10 also has grey subtitles
  
• mkv playback of HDR source from Vero to an SDR display also has grey subtitles
  
• mkv playback of native SDR bluray Godfather to an SDR or HDR display has the correct yellow subtitles across platforms
  

[graham-h]

According to this subtitle images on BR are stored as YCC but there's no provision for specifying the colorimetry.  I haven't found a similar explanation of the subtitle format on UHD disks and whether it now includes colorimetry but if that colorimetry is being misinterpreted by Kodi then the subtitle colours will be affected.

[graham-h]

Or maybe @Karellen has it right and it's MakeMKV that doesn't interpret the colours properly.  That is, it understands BD subtitles but not UHD subtitles.

[ac16161]

An Oppo owner on the OSMC forum has tested mkv playback of a UHD rip and the Oppo plays the subtitles in the correct gold colour, so this looks like it's a Kodi bug?

https://discourse.osmc.tv/t/pgs-subtitle...r/92829/24

[Klojum]

What media player does the Oppo use? (I probably overlooked it)

[CastagnaIT]

i also found a 4k HDR rip of that movie
and subtitles are shown as this link screenshot (Kodi 20 nightly on Windows10 / non-HDR monitor):
https://ibb.co/56YJtBQ

how yellow should they look?
i looked at your forum link but to me seem more similar to Oppo

[Hitcher]

Definitely not grey for me on Windows/Kodi, Shield/Kodi, or Shield/Plex.

They all look like this -

[ac16161]

Here is what I get with Windows 10/Kodi 20, with a regular SDR BenQ monitor. Subtitle colour is way off correct:



The following image was posted on the OSMC forum where a user has played the mkv on an Oppo, this is what the subs should look like:

[Hitcher]

Colours look overblown in that screenshot to me though.

EDIT: Also tested using VLC on Windows and they look the exact same as my previous post so VLC, PLEX, and Kodi results are all the same. Conclusion - it's not Kodi.

[CastagnaIT]

i have tested also on VLC and MPV players and subtitles colors are the same of Kodi

i dont think that all video player softwares display in wrong way
could be that Oppo apply some kind of color conversion that we are not aware
(to take also in account taking photos externally is not the same as a screenshot, colours could also be more/less saturated than the real thing)

IMO i don't see a real certainty of a bug in Kodi
it might be an idea to see the result also on a Linux operating system (computer not boxes)

[CastagnaIT]

but i see also that subtitles are excluded from tone mapping
so on Windows ALT+F11 to change it
I don't know if this would add the exact shade

rendering is not my field i can't give an answer if tone mapping should be applied also to subtitle rendering
maybe @thexai @jogal can give some info?

[ac16161]

I have looked at this on multiple Kodi platforms (Vero, Shield, Windows), also Plex/Shield and Infuse Pro/Apple TV, and not one of these platforms matches the yellow/gold colour that is produced via direct disc playback. All these platforms get the colour correct for the bluray rip, but none of them match disc playback for the UHD source.