[MPlayer-users] Stream selection matroska vs others

[John Philip]

Mplayer handles the arguments to the -aid and -sid options differently 
for matroska (.mkv) and other file formats. In other container formats, 
the argument given to -aid or -sid is the stream number in the file. 
For matroska however, the argument is the audio stream number for aid, 
and the subtitle stream number for sid.

To explain, assume we have a .mkv file and an .ogm file with identical 
streams, in this order: Video, Audio, Audio, Subtitle. If we wanted to 
play the second audio stream and the subtitle stream, different 
arguments are required:
file.mkv -aid 1 -sid 0
file.ogm -aid 2 -sid 3

Obviously, the -aid and -sid arguments need to behave consistently. 
However, I think the new matroska behavior is preferable. The old 
system, like is used for .ogm files, requires a user to know the order 
of every stream in the file. The new system only requires a user to 
know which audio stream they want, or which subtitle stream they want. 
This is much more logical and much simpler to use.

Additionally, If mplayer did adopt this system, it would make further 
sense to make have the arguments 1-based. If you want to play the first 
audio track, you use -aid 1. If you want the second audio track, it's 
-aid 2, and so on.

Thanks for your thoughts,
John
(using CVS tarball 20040212)