Shouldn't Forced Subtitles Automatically Get the 'f' MKV Flag?

Discussion of advanced MakeMKV functionality, expert mode, conversion profiles
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peter0302
Posts: 7
Joined: Wed Feb 21, 2024 4:44 pm

Shouldn't Forced Subtitles Automatically Get the 'f' MKV Flag?

Post by peter0302 »

When extracting "Forced Only" subtitle tracks, MKV successfully identifies the right subset of subtitles to include, but I find myself having to manually add the "f" flag to the MKV metadata, either in MakeMKV itself or later with MkvToolNix, otherwise the forced subtitles don't work correctly with Plex.

With Game of Thrones for example I had to add this for every episode since they make extensive use of subtitle tracks when speaking Dothraki, Valyrian, etc. The 'd' flag was added automatically, but I had to manually add 'f' each time.

So I was just wondering why MakeMKV wouldn't automatically add the "f" flag when extracting any Forced Subtitle track and (as a paying user! :)) I thought I'd make that suggestion.

Thanks!
Woodstock
Posts: 10331
Joined: Sun Jul 24, 2011 11:21 pm

Re: Shouldn't Forced Subtitles Automatically Get the 'f' MKV Flag?

Post by Woodstock »

Just a comment that the forced flag in MKVs isn't 100% universal anyway. Some players want the default flag, some want forced, some want both. And subsequent tools may UN-set them, even if you could set them in MakeMKV. Plex just adds their prejudices to the mix.

I've got a script that I run on my stuff. The handbrake portion is tweaked to put the forced subtitle track first, followed by the full track, and finally mkvtoolnix runs to set the "name" properly, and put both "F" and "D" flags on the first subtitle track. When dealing with dozen or two episodes of an anime series at a time, it's the best way I've found.
Mr. Red
Posts: 20
Joined: Wed Nov 01, 2023 10:19 am

Re: Shouldn't Forced Subtitles Automatically Get the 'f' MKV Flag?

Post by Mr. Red »

It depends if the subtitles are marked as forced on the subtitle track itself or are simply selected by the language selection from the disc menu.
If the subtitle track contains the forced flag(s) you can configure MakeMKV to set the flag in the resulting mkv file.

You have to use your own customized mmcp.xml.
see: viewtopic.php?f=1&t=24935&p=113744&hili ... ag#p113744


Personally I encountered only a few discs where the forced flags could be set automatically by MakeMKV. So it's always a good idea to check the files in mkvtoolnix.
If you rip a show with multiple episodes, normally the track order is the same for all of them. You could use JMkvpropedit for batch adding the flags for all of the episodes.
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