FFmpeg gives the codec too. Pull the Stream #0.0: Video
line and you can see the codec. (Be aware that it could technically have a different stream number, like 0.1.) The below output uses the MS Video-1. This is different, like you desire, from the container which is denoted by Input #0, avi
E.g.:
FFmpeg version 0.5, Copyright (c) 2000-2009 Fabrice Bellard, et al.
configuration: --prefix=/opt/local --disable-vhook --enable-gpl --enable-postproc --enable-swscale --enable-avfilter --enable-avfilter-lavf --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-libdirac --enable-libschroedinger --enable-libfaac --enable-libfaad --enable-libxvid --enable-libx264 --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/gcc-4.2 --arch=x86_64
libavutil 49.15. 0 / 49.15. 0
libavcodec 52.20. 0 / 52.20. 0
libavformat 52.31. 0 / 52.31. 0
libavdevice 52. 1. 0 / 52. 1. 0
libavfilter 1. 4. 0 / 1. 4. 0
libswscale 1. 7. 1 / 1. 7. 1
libpostproc 51. 2. 0 / 51. 2. 0
built on Jan 8 2010 15:34:15, gcc: 4.2.1 (Apple Inc. build 5646) (dot 1)
Input #0, avi, from 'Movies/fvss_demo.avi':
Duration: 00:02:00.30, start: 0.000000, bitrate: 719 kb/s
Stream #0.0: Video: msvideo1, rgb555, 160x120, 10 tbr, 10 tbn, 10 tbc
Stream #0.1: Audio: pcm_u8, 8000 Hz, mono, s16, 64 kb/s
At least one output file must be specified
manoa:~ stu$