Invisible PGS subtitles track in MKVToolNix

[GD314]

Hi

I'm trying to remux a mvk file to remove and re-order some tracks. It contains a set of 4 subtitles tracks (PGS format), the last one is forced as indicated in MPC-HC menus :

https://wydbha-dm2305.files.1drv.com/y3myhmKq46j99HiTHp4hhY5rBaXwnV4BqdkAZoKf6sZMQ54R1LTwP5g52xQoxBph2fBhBMpDkMX9YRPxs4NELZ8e2aP5sgYa_U2jO2LNwP8fyYQdabEn5x7EsYWEp5Jym1kKXGoCAi9Flry0BHQHzKzDYm1jL_3Zb9ZkVMqWsf4cDs?width=373&height=330&cropmode=none

The strange thing, is once in MKVToolNix, this 4th track doesn't appear :

https://wycpha-dm2305.files.1drv.com/y3mVB0ln6ftQj1HDoYTsO5h4DzZeBREYJga7eLCRXnI7Uh4qzdBL8vWP0XIqJ8-NHCID9cag2vF05lj443R9IYR2cXquwzdYAsywrcZ1odDGbBabxqdcF-BVb1xcu_HhlL5B4OCbVqy4cS1mwu26e5yG8l9xGNfnT2RO-eUicpBj1Q?width=554&height=202&cropmode=none

The remux process results in a file containing only the first 3 subtitles tracks, and none is forced anymore. The text that was in the 4th track seems to be incorporated in the first french track as it displays when the remaining french track is selected. But I have to force it manually, and the text of the whole movie displays, instead of only what was in the initial forced track.

Do you confirm MKVToolNix won't detect forced PGS tracks ? Is this track a "virtual" track which is incorporated in the initial track (a sort of subset or forced text) ? And how to keep it intact when remuxing the file ?

Thanks for your help!

[sneaker_ger]

The 4th PGS track does not exist. It is a virtual track created by MPC-HC's LAV Splitter. In LAV Splitter options you can turn it on/off ("Enable Automatic Forced Subtitle Stream"). It filters one of the 3 other streams.

If you want it you have to extract the corresponding track (of the 3), filter out non-forced lines (e.g. using BDSup2Sub) and then add it manually in mkvmerge.

[GD314]

Hi sneaker_ger

Thanks for the answer, it's perfectly clear.
One last question though : do you confirm that remuxing with MKVToolNix changes something, as the LAV splitter doesn't show the virtual track anymore after remuxing (even though some lines are still forced in the stream)?
Just downloaded BDSup2Sub and playing with it.

[sneaker_ger]

I cannot confirm. Remuxing using MKVToolNix should not change anything. Please check again.

[GD314]

Hi
It does.
I did it at least 20 times, and each time the virtual forced stream disappears. You can force the track in MKVToolNix, but then the whole stream is forced.

[sneaker_ger]

When you play such a muxed file where forced track disappears click "Play"->"Filters"->"LAV Splitter [...]" to make sure:
a.) LAV Splitter is actually being used and
b.) the "Enable Automatic Forced Subtitle Stream" setting is set for that specific LAV Splitter instance. There might external and internal LAV filters with separate settings storage.
c.) you see all streams as LAV Splitter does

[GD314]

Hi sneaker_ger

Indeed, MKVToolnix leaves the stream intact, including the virtual forced stream. I cannot reproduce the issue I mentioned earlier in this post... and I can't figure out how I succeeded this, as I have only one MPC-HC installed using the internal LAV filters with the "Enable Automatic Forced Subtitle Stream" on. So, how come a stream appears in MPC-HC and disappears within the same MPC-HC instance after remuxing?
I tried to install the version of MKVToolnix I had at that time but no way : everything works normally, which seems very odd to me :sly:

Thanks for the answers anyway.