[MEncoder-users] Mencoder not stopping with x264

[cr]

[I hope I'm not asking something that's already been answered but I can't find 
a 'search' function for the archives]

I'm ripping some tracks off DVDs and I'd like to use the x264 codec as it 
gives much better video quality in a small file size than lavc

However, it doesn't seem to want to stop on -endpos 

I can use 
mencoder dvd://1 -ss 00:52:32 -oac copy -ovc x264 -x264encopts bitrate=1200 
- endpos 00:09:30 pass=1 -o /dev/null
(and for the second pass,  pass=2  -o filename.avi)

Or I can use  mencoder dvd://1 -chapter 12    instead of -ss and -endpos

Either way, it starts in the right place but just doesn't stop.   (It stops 
fine with the lavc codec in place of x264)

I can stop it manually with Ctrl-C on both passes, and then trim it to length 
with  
mencoder -endpos 00:09:30 -oac copy -ovc copy filename.avi -o trimmed.avi
but this is a bit tedious.

Am I doing something wrong?