gif muxer should not be gif encoder

[llogan]

Despite the error message the current behaviour is confusing to some users. Having rgb24 automatically chosen may be more convenient, but perhaps I am missing something.

$ ffmpeg -f lavfi -i color -vframes 1 output.gif
ffmpeg version N-49812-g0aa1d84 Copyright (c) 2000-2013 the FFmpeg developers
  built on Feb 11 2013 11:54:39 with gcc 4.7.2 (GCC)
  configuration: --prefix=/usr --enable-gpl
  libavutil      52. 17.101 / 52. 17.101
  libavcodec     54. 91.102 / 54. 91.102
  libavformat    54. 62.100 / 54. 62.100
  libavdevice    54.  3.103 / 54.  3.103
  libavfilter     3. 37.101 /  3. 37.101
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
[lavfi @ 0x2beffc0] Estimating duration from bitrate, this may be inaccurate
Input #0, lavfi, from 'color':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 320x240 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
[gif @ 0x2bf1720] ERROR: gif only handles the rgb24 pixel format. Use -pix_fmt rgb24.
Output #0, gif, to 'output.gif':
  Metadata:
    encoder         : Lavf54.62.100
    Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 320x240 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo -> rawvideo)
Could not write header for output file #0 (incorrect codec parameters ?): Input/output error

[cehoyos]

The other users of the rawvideo encoder would be unhappy if rgb24 were auto-selected.

[ubitux]

Patch on the mailing list.

[ubitux]

Fixed in 635389c.