I have a .mkv file that has MPEG-4p10/AVC/h.264 video, two DTS audio tracks, and one HDMV PGS subtitles track. When I play this .mkv file in (an old) VLC, the subtitles show OK.
When I convert the .mkv file to Mpeg4 AVC (x264) in Avidemux 2.7.3, and play it as Play Filtered to check before conversion, I can't see the subtitles.
The only option I have seen to include subtitles is with the SSA/ASS/SRT filter. But it asks for a separate subtitles file. And I don't have one, since the subtitles are already in the .mkv file.
Any way I can get the PGS subtitles just hardcoded in the target Mpeg4 file?
Avidemux does not support subtitle tracks, no matter which type. Is hardcoding of subtitles really unavoidable for you? If yes, you should be able to accomplish this with the tool Handbrake.
I shall try Handbrake, thanks for your time.
Restore the subtitles into the result
You can merge the output of Avidemux ( no soft subtitles) with the original MKV using MKVTOOLNIX GUI by selecting only the subtitles you want.