[VU+ Solo2] Defaukt Media Player and muxed .srt sutitles in mkv files

[QMax]

This question is not for a problem, but just for my curiosity.
My question is related to default Media Player in ViX images.
Is this the original Media Player coming from VU+ or has been modified by ViX Team ?
I'm asking because I was absolutely not able to play mkv files containing multiple subs track (srt format) embedded, until I tried OpenViX,
where I can select the sub track that I need without problem.
ALL other images I tested can show only the first sub track, all other track doesn't appear at all in the sub list.
I tested on original VU+ Image, BH, PLi.

It's just a curiosity.

Thanks

Max