[lovewangbo]

I am from a non-English country, and I used to collect the subtitles of English as well as my native language almost for every movie. In recent years, a growing number of subtitle files are in the form of ".sup" as they are demuxed from BD sources.
At present, kodi only support internal sup subtitles and doesn't support the external ones. Thus, the external sup files need to be muxed with the main media file just to make them can be played by kodi, almost every time. Such a mux work may take tens of minutes, especially for the intact BD sources with large sizes. Moreover, the original materials, i.e., main media files, external subtitle files and external audio files, need to be kept for potential version updating. 
It would be wonderful if kodi supports external sup subtitles as srt/idx/sub ones directly.

[jjd-uk]

If use you using intact BD sources then why aren't the subs part of the rip?

[lovewangbo]

If use you using intact BD sources then why aren't the subs part of the rip?

This situation arises from the way I collect materials. There are roughly three ways to meet my demand for additional subtitles/audios:
(1) DIY-ed Media sources released by native groups with embedded subtitles/audios; 
(2) Mux the collected subtitles/audios with the main media sources as new files by myself;
(3) Main media sources in original language (most ones are English) + external subtitles/audios in my native language (collected from various sources, including BDs, induce this requested demand); 
The main drawback of first two ways is that the media files cannot flexibly update part of the tracks (subtitle/audio or even video) when I find a media source with better track(s). And they lose the common attribute as the original media files are modified. Moreover, it's extremely difficult to make a choice between different sources in the first way because one may have better video quality only and another has a better subtitle/audio. The last way, I am using at present, can provide the most balanced compromise between flexible updating and convenient usage.
On the platform of windows, we can use Potplayer as alternative, which support external sup subtitles. However, on the other platform such as Android, I have to mux a temporary file for kodi just to play the needed subtitles.
By the way, I would like to clarify the necessity and advantage of using sup subtitles. The sup subtitles, which are usually made by DIY group and can be demuxed from DIY BDs, can provide special effects such as watermark accompanying the text on the screen, as well as softer contrast when we enjoy HDR media sources.

[QianyuLi]

With the PR #20245 merge, Kodi v20 (Nexus) Nightly now supports scanning for SUP subtitles of the same name from the Custom Subtitles folder. However, mounting from within the GUI Dialog SubtitleSettings Subtitles Browser is not supported.
It only works with Kodi VideoPlayer, not with streaming add-ons.
Are there technical barriers or legal issues with mounting PGS (SUP) subtitles?
PS: I found that by using BDSup2Sub to convert PGS(SUP) subtitles to VobSub(IDX + SUB) format. kodi can mount it.

[CastagnaIT]

However, mounting from within the GUI Dialog SubtitleSettings Subtitles Browser is not supported.
It only works with Kodi VideoPlayer, not with streaming add-ons.
Are there technical barriers or legal issues with mounting PGS (SUP) subtitles?

i think that currently is missing an implementation to load .sup files in appropriate way
i don't see many requests from users for this file type, which is probably why this addition has never been a priority

[QianyuLi]

However, mounting from within the GUI Dialog SubtitleSettings Subtitles Browser is not supported.
It only works with Kodi VideoPlayer, not with streaming add-ons.
Are there technical barriers or legal issues with mounting PGS (SUP) subtitles?

i think that currently is missing an implementation to load .sup files in appropriate way
i don't see many requests from users for this file type, which is probably why this addition has never been a priority

The proper way? I think the fact that only a few users have made that request is the biggest reason why PGS (SUP) cannot be external mounted yet - after all, Kodi is an open source project and developers have limited time.
Let me explain the reason for that request, for some small languages and for some special markets (e.g. China), the audience may have no choice. The Legitimate Sources does not include native languages. So the only options are DIY Blu-ray Rip or external subtitles on streaming services. And now some Chinese Fansub (I don't know the rest of the world) only release PGS (SUP) subtitles to protect their translation "copyright". This may sound unbelievable, but Fansub does have an incentive to do so, as someone may simply delete the translator information and suppress it into hard subtitles for illegal distribution.
So for now if I want to external mounted PGS(SUP) subtitles within a Kodi streaming service add-on it is not possible. the only options are to OCR PGS(SUP) subtitles to text-based subtitles, or to convert PGS(SUP) to VobSub (IDX + SUB). The former requires troublesome proofreading, the latter loses and changes color.

[CastagnaIT]

Thanks for your explanation the background is more clear
only to be more clear, if several users request the same feature is more likely to have a higher priority than other feature requests,
but other factors can influence this, some are: a feature must be compatible with the development, may require to be evaluated within the Kodi team, may require more then one developer who have experience in specifics areas of source code and give their personal time to implement and test it, and a feature can only be implemented to the first stage of Kodi development of each new Kodi version.

so if a feature is not implemented current version, it might mean that will be implemented in the next Kodi version, then do not panic if it is not done immediately,
of course, we accept also that external developers collaborate to implement them, this is appreciated and could speed things up
 

The proper way?

not all subtitles are managed in same way, at a glance to load SUP as external file seem missing the implementation,
SUP files are managed by FFMPEG, i took care of the subtitle management but i do not have experience on how works FFMPEG to load subtitles,
then to understand how to do this i would have to study the whole process and require much time

[QianyuLi]

@CastagnaIT
Thanks for the additional information, after all, even if Kodi 20 is too late to implement it, we can expect to implement PGS (SUP) external mounts in the future. Maybe Kodi 21 or Kodi 22.

Actually, about SUP external mount, Chinese XBMC developer (author taxigps of PR #20405) has already tried to implement it in Chinese blog which mentions that

Kodi uses FFmpeg library to separate and decode PGS subtitles encapsulated in video files, and should be able to decode individual sup files with FFmpeg as well. Looking at the source code of FFmpeg, there is already a separator for .sup files. All things considered, let's modify the Kodi code.

So @taxigps, can you work with @CastagnaIT to make it happen? Maybe it's not too late to implement it in Kodi 20.
I believe the implementation of this feature helps more people than just him.

Anyway, thanks to all the developers for their contributions to Kodi. Especially you CastagnaIT, the subtitle module is a very important part for more people (like me lol) to enjoy entertaining content through Kodi. I hope one day I can be part of it.

[taxigps]

@CastagnaIT
Thanks for the additional information, after all, even if Kodi 20 is too late to implement it, we can expect to implement PGS (SUP) external mounts in the future. Maybe Kodi 21 or Kodi 22.

Actually, about SUP external mount, Chinese XBMC developer (author taxigps of PR #20405) has already tried to implement it in Chinese blog which mentions that

Kodi uses FFmpeg library to separate and decode PGS subtitles encapsulated in video files, and should be able to decode individual sup files with FFmpeg as well. Looking at the source code of FFmpeg, there is already a separator for .sup files. All things considered, let's modify the Kodi code.

So @taxigps, can you work with @CastagnaIT to make it happen? Maybe it's not too late to implement it in Kodi 20.
I believe the implementation of this feature helps more people than just him.

Anyway, thanks to all the developers for their contributions to Kodi. Especially you CastagnaIT, the subtitle module is a very important part for more people (like me lol) to enjoy entertaining content through Kodi. I hope one day I can be part of it.

I'll try to do this when have time.

[QianyuLi]

@CastagnaIT
Thanks for the additional information, after all, even if Kodi 20 is too late to implement it, we can expect to implement PGS (SUP) external mounts in the future. Maybe Kodi 21 or Kodi 22.

Actually, about SUP external mount, Chinese XBMC developer (author taxigps of PR #20405) has already tried to implement it in Chinese blog which mentions that

Kodi uses FFmpeg library to separate and decode PGS subtitles encapsulated in video files, and should be able to decode individual sup files with FFmpeg as well. Looking at the source code of FFmpeg, there is already a separator for .sup files. All things considered, let's modify the Kodi code.

So @taxigps, can you work with @CastagnaIT to make it happen? Maybe it's not too late to implement it in Kodi 20.
I believe the implementation of this feature helps more people than just him.

Anyway, thanks to all the developers for their contributions to Kodi. Especially you CastagnaIT, the subtitle module is a very important part for more people (like me lol) to enjoy entertaining content through Kodi. I hope one day I can be part of it.

I'll try to do this when have time.

Thank you, I will wait patiently.

[taxigps]

Done. see: 20471 (PR)

[QianyuLi]

Thanks to a contribution from taxigps, Kodi supports PGS (.SUP) external subtitles starting with v20 (Nexus) Nightly (Git:20211110-61becb5c).
The following post can be marked as "Solved"
OUYA force external SUP subtitles
Supporting external sup subtitles
Support external sup subtitles