$ ffmpeg -i Hel.wmv -pix_fmt rgb24 Hel.gif
FFmpeg version SVN-r15986, Copyright (c) 2000-2008 Fabrice Bellard, et al.
  configuration: --extra-cflags=-fno-common --enable-memalign-hack --enable-pthr
eads --enable-libmp3lame --enable-libxvid --enable-libvorbis --enable-libtheora
--enable-libspeex --enable-libfaac --enable-libgsm --enable-libx264 --enable-lib
schroedinger --enable-avisynth --enable-swscale --enable-gpl
  libavutil     49.12. 0 / 49.12. 0
  libavcodec    52. 6. 0 / 52. 6. 0
  libavformat   52.23. 1 / 52.23. 1
  libavdevice   52. 1. 0 / 52. 1. 0
  libswscale     0. 6. 1 /  0. 6. 1
  built on Dec  3 2008 01:59:37, gcc: 4.2.4
[wmv3 @ 0x3ee7b0]Extra data: 8 bits left, value: 0

Seems stream 1 codec frame rate differs from container frame rate: 1000.00 (1000
/1) -> 30.00 (30/1)
Input #0, asf, from 'Hel.wmv':
  Duration: 00:00:00.53, start: 2.000000, bitrate: 3420 kb/s
    Stream #0.0: Audio: wmav2, 44100 Hz, stereo, s16, 96 kb/s
    Stream #0.1: Video: wmv3, yuv420p, 640x480, 768 kb/s, 30.00 tb(r)
File 'Hel.gif' already exists. Overwrite ? [y/N] y
[swscaler @ 0x176c010]No accelerated colorspace conversion found.
Output #0, gif, to 'Hel.gif':
    Stream #0.0: Video: rawvideo, rgb24, 640x480, q=2-31, 200 kb/s, 30.00 tb(c)
Stream mapping:
  Stream #0.1 -> #0.0
[wmv3 @ 0x3ee7b0]Extra data: 8 bits left, value: 0
Press [q] to stop encoding
frame=   56 fps= 12 q=0.0 Lsize=   19259kB time=1.87 bitrate=84519.4kbits/s
video:50400kB audio:0kB global headers:0kB muxing overhead -61.787764%