Hi,
I recently switched to using mplayer2 for the mkv ordered chapters support. I watch on my 16/9 TV, so I use the SMPlayer "Advanced --> Monitor aspect --> 16/9" option. (On a sidenote; I don't know how this option works, as I don't see it in the mplayer log :S) With mplayer this works fine, but mplayer2 seems to ignore this option. When I add "-monitoraspect=16:9" to "Advanced --> Options for MPlayer" the log says "Unknown option on the command line: --monitoraspect=16:9".
Also, when I open the video through the command line with mplayer2 with the -monitoraspect=16:9 option, it works just fine.
Oh, and I use the MPlayer2 2.0-704-gbb88251 Custom build by Redxii.