I wanted to display MKV subtiles by pressing the "S" button on the keyboard, so i changed the setting for input.conf and added s dvdsublang but nothing happens when i press the button.
The subtitles display fine when i insert mplayer -slang chi /home/hao/multi/anime/1.mkv

Playing /home/hao/multi/anime/1.mkv.
[mkv] Track ID 1: video (V_MS/VFW/FOURCC), -vid 0
[mkv] Track ID 2: audio (A_VORBIS), -aid 0, -alang eng
[mkv] Track ID 3: sutitles (S_TEXT/SSA), -sid 0, -slang chi
[mkv] Track ID 4: sutitles (S_TEXT/SSA), -sid 1, -slang chi
[mkv] Will play video track 1
[mkv] Will play audio track 2
[mkv] Will display subtitle track 3
Matroska file format detected.
dvdsublang...1 chi

however if i just play the mkv in the gmplayer it doesnt display any subtitle and when i press the s key i get this error
Invalid command for bound key s : dvdsublang