[MPlayer-users] subtitle disordered when using slave mode

[Zongyao QU]

how to reproduce the bug?

1. open a file with internal subtitle, for example, XXX.mkv
 ./mplayer -slave -quiet -font xxx.ttf  XXX.mkv

2. set_property sub 0

then you could make sure that 0 means 
the internal sub track.

3. use sub_load to load another subtitle
sub_load aaa/bbb/ccc.srt

4. set_property sub 0

you will see that the ccc.srt will be displayed.

but

set_property sub 1 

will make internal sub displayed.

I think the sub track id should be consistent, but it is not

and this seams only happens when
1. internal + external sub
2. external sub should be loaded in the runtime, 
     rather than by the cmdline