Works, but not so good with colors

./ffmpeg-1.2.7/ffmpeg -i movie_to_be_animated.mp4 -pix_fmt rgb24 output.gif
ffmpeg version 1.2.7 Copyright (c) 2000-2014 the FFmpeg developers
  built on Aug  6 2014 05:22:16 with gcc 4.6 (Ubuntu/Linaro 4.6.4-1ubuntu1~12.04)
  configuration:
  libavutil      52. 18.100 / 52. 18.100
  libavcodec     54. 92.100 / 54. 92.100
  libavformat    54. 63.104 / 54. 63.104
  libavdevice    54.  3.103 / 54.  3.103
  libavfilter     3. 42.103 /  3. 42.103
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'movie_to_be_animated.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf53.21.1
  Duration: 00:00:12.52, start: 0.000000, bitrate: 963 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 220x220 [SAR 1:1 DAR 1:1], 960 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
    Metadata:
      handler_name    : VideoHandler
Output #0, gif, to 'output.gif':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf54.63.104
    Stream #0:0(und): Video: rawvideo (RGB[24] / 0x18424752), rgb24, 220x220 [SAR 1:1 DAR 1:1], q=2-31, 200 kb/s, 90k tbn, 25 tbc
    Metadata:
      handler_name    : VideoHandler
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> rawvideo)
Press [q] to stop, [?] for help
frame=  313 fps=0.0 q=0.0 Lsize=   16965kB time=00:00:12.52 bitrate=11100.5kbits/s
video:44382kB audio:0kB subtitle:0 global headers:0kB muxing overhead -61.775097%