ffmpeg -i audio1.ogg -ab 128kb audio1.mp3
FFmpeg version SVN-r0.5.4-4:0.5.4-1, Copyright (c) 2000-2009 Fabrice Bellard, et al.
configuration: --extra-version=4:0.5.4-1 --prefix=/usr --enable-avfilter --enable-avfilter-lavf --enable-vdpau --enable-bzlib --enable-libdirac --enable-libgsm --enable-libopenjpeg --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvorbis --enable-pthreads --enable-zlib --disable-stripping --disable-vhook --enable-runtime-cpudetect --enable-gpl --enable-postproc --enable-swscale --enable-x11grab --enable-libfaad --enable-libdc1394 --enable-shared --disable-static
libavutil 49.15. 0 / 49.15. 0
libavcodec 52.20. 1 / 52.20. 1
libavformat 52.31. 0 / 52.31. 0
libavdevice 52. 1. 0 / 52. 1. 0
libavfilter 0. 4. 0 / 0. 4. 0
libswscale 0. 7. 1 / 0. 7. 1
libpostproc 51. 2. 0 / 51. 2. 0
built on Mar 26 2011 22:50:57, gcc: 4.4.5
Input #0, ogg, from 'audio1.ogg':
Duration: 00:06:23.15, start: 0.000000, bitrate: 139 kb/s
Stream #0.0: Audio: vorbis, 44100 Hz, stereo, s16, 160 kb/s
Output #0, mp3, to 'audio1.mp3':
Stream #0.0: Audio: 0x0000, 44100 Hz, stereo, s16, 128 kb/s
Stream mapping:
Stream #0.0 -> #0.0
Unsupported codec for output stream #0.0