[MPlayer-users] Problems coding to 3gp

[Sebastián Lacuesta]

Hi, I wanted to use mencoder to encode a video file to 3gp. The command line
I used was:

mencoder AnInputFile.ext -o TheOutputFile.3gp -of lavf -oac lavc -ovc lavc
-srate 8000 -vf scale=176:144 -ofps 12 -channels 1 -lavcopts
vcodec=h263:acodec=libopencore_amrnb:abitrate=12200

It encodes the video very well, but the problem is the audio. If the input
file has 1 audio channel, sound is recorded very fast, and naturally ends
before video. When input file has more than 1 audio channel I get a message
that says:
[libopencore_amrnb @ 0x2bc1190]Only mono supported
Looks like the "-channels 1" option is ignored.

My question is: what I'm doing wrong?
Thanks!