Dub Flag in mkv

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1

Hey! Wondering if you could help me. I’m organizing my library, my final goal is to get rid of all unnecesary tracks in my mkvs and flag them all the same. So i have video (default) - audio (default) - en (noflag) - en (sdh-hearing impaired). All other flags are set to 0 and have no naming except for the SDH track.

Because I use the GUI I started to inspect the files with a ffprobe script that outputs track languages and flags and then batch remove any unwanted flag before remuxing. The problem is with the “Original” flag. Because not many files have it I decided to remove it altogether from all files. But it turns out, according to ffprobe, when I set the “Original” flag to 0, regardless if it’s in the GUI or with a mkvpropedit script, it will set the “Dub” flag to 1. I know dub isn’t an official mkv flag but I would appreciate if someone would answer if this is normal behaviour and if this “dub” flag may have unexpected results with some players. For example I don’t have Plex at the moment but I plan to and was wondering if this may break something.

I’ll put the output from ffprobe before/after. Thanks!

[VIDEO] Track #0
Language : und
Flags : default

[AUDIO] Track #1
Language : eng
Flags : default

[SUBTITLE] Track #2
Language : eng
Flags : original

[SUBTITLE] Track #3
Language : eng
Title : SDH
Flags : original, hearing_impaired

[VIDEO] Track #0
Language : und
Flags : default, dub

[AUDIO] Track #1
Language : eng
Flags : default, dub

[SUBTITLE] Track #2
Language : eng
Flags : dub

[SUBTITLE] Track #3
Language : eng
Title : SDH
Flags : dub, hearing_impaired

This is the command for propedit

for /r %%f in (*.mkv) do @(echo Processing: %%f & mkvpropedit “%%f” --edit track:v1 --set “flag-original=0” --edit track:a1 --set “flag-original=0” --edit track:s1 --set “flag-original=0” --edit track:s2 --set “flag-original=0”).

Files that haven’t been modified this way and didn’t have the “Original” flag in the first place are shown in ffprobe like original=0, dub=0.

2

I actually figured out that using –delete flag-original sets original and dub to 0 in ffprobe but my question remains, considering there’s no way to delete it in the gui, is there any downside to this dub=1 flag?

3

Sorry to come back to this but I was wondering what is the best practice regarding flags. Right now there is no way I am aware of to just remove flags with mkvmerge or the multiplexer. I’ve read the doc and haven’t found anything. The objective would be a “clean” remux, considering that the source may have been full of junk (for example a track may have 3-4 flags but only one would be necessary). When remuxing you have only the option to set to 0, you have to use propedit to actually remove it. There are some exceptions: if forced=0 it will not be written as an element, but if hearing impaired=0 it will be written. I’ve searched all I could about this inconsistency but no result.

My question: is there any downside of keeping all these flags present (0, but present), except for the congestion.

Also regarding the language(legacy) and language(IETF), mkvmerge will only add IETF if language is english (english is default for the legacy element so it will not add it as an element), but propedit will add both if language=eng. Which path is better? Same goes for the default flag.

Any answer would be appreciated! Thanks!