ffmpeg -i history.wmv -b 600 -s 320x240 -ab 128k -vcodec mpeg4 -ab 128 -acodec aac output.mp4
ffmpeg version 0.8.1-4:0.8.1-0ubuntu1, Copyright (c) 2000-2011 the Libav developers
  built on Mar 22 2012 05:29:10 with gcc 4.6.3
This program is not developed anymore and is only provided for compatibility. Use avconv instead (see Changelog for the list of incompatible changes).
[asf @ 0x9ff7240] max_analyze_duration reached
Input #0, asf, from 'history.wmv':
  Metadata:
    WMFSDKVersion   : 10.00.00.3708
    WMFSDKNeeded    : 0.0.0.0000
    VBR Peak        : 108
    Buffer Average  : 229
    IsVBR           : 1
  Duration: 00:19:01.03, start: 0.000000, bitrate: 40 kb/s
    Stream #0.0: Audio: wmavoice, 22050 Hz, 1 channels, flt, 20 kb/s
    Stream #0.1: Video: MSS2 / 0x3253534D, 800x600, 15 kb/s, 1k tbr, 1k tbn, 1k tbc
[buffer @ 0x9ff77c0] Invalid pixel format string '-1'
Error opening filters!