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!