Subler doesn't support aliased ISO language codes

[Natalia Portillo]

I've seen when muxing from language tagged MKVs to MP4 (both using ffmpeg for the mux and subler directly) that subler does not recognize the language codes used by them when there're aliases.

I've experienced it on German ("ger" found, Subler expects "deu"), French ("fre"/"fra"), Dutch ("dut"/"nld"), Romanian ("rum", "ron"), Modern Greek ("gre", "ell"), Czech ("cze", "ces").

I have however not seen the problem with Farsi (Persian).

[Damiano Galassi]

Works here. Please note that mp4 uses ISO 639-2/T, if you have "ger" or "fre" in a mp4 it means that the mp4 is invalid.