ffmpeg for noobie. MPG to 3GP

anonymous@anonymous:/tmp$ file input.mpg 
input.mpg: MPEG sequence, v1, system multiplex
anonymous@anonymous:/tmp$ ffmpeg -i input.mpg -s qcif -vcodec h263 -acodec mp3 -ac 1 -ar 8000 -ab 32 -y clip.3gp
FFmpeg version SVN-rUNKNOWN, Copyright (c) 2000-2007 Fabrice Bellard, et al.
  configuration: --enable-gpl --enable-pp --enable-swscaler --enable-pthreads --enable-libvorbis --enable-libtheora --enable-libogg --enable-libgsm --enable-dc1394 --disable-debug --enable-shared --prefix=/usr
  libavutil version: 1d.49.3.0
  libavcodec version: 1d.51.38.0
  libavformat version: 1d.51.10.0
  built on Jun  3 2007 20:59:25, gcc: 4.1.3 20070528 (prerelease) (Ubuntu 4.1.2-9ubuntu2)
Input #0, mpeg, from 'input.mpg':
  Duration: 00:00:17.8, start: 0.674333, bitrate: 914 kb/s
  Stream #0.0[0x1e0]: Video: mpeg1video, yuv420p, 384x288, 725 kb/s, 25.00 fps(r)
  Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, stereo, 64 kb/s
Output #0, 3gp, to 'clip.3gp':
  Stream #0.0: Video: h263, yuv420p, 176x144, q=2-31, 200 kb/s, 25.00 fps(c)
  Stream #0.1: Audio: 0x0000, 8000 Hz, mono, 0 kb/s
Stream mapping:
  Stream #0.0 -> #0.0
  Stream #0.1 -> #0.1
Unsupported codec for output stream #0.1
anonymous@anonymous:/tmp$

Что оно хочет? Можно как-нибудь сделать аудиопоток под aac-lc? Спасибо!