Support KLFS files

[cehoyos]

A user has uploaded a sample file that contains jpeg frames and starts with a short header starting with "KLFS".

$ ffmpeg -f mjpeg -i Video
ffmpeg version N-49518-g911e270 Copyright (c) 2000-2013 the FFmpeg developers
  built on Feb  1 2013 16:26:12 with gcc 4.7 (SUSE Linux)
  configuration: --enable-gpl --disable-indev=jack
  libavutil      52. 17.100 / 52. 17.100
  libavcodec     54. 91.100 / 54. 91.100
  libavformat    54. 61.104 / 54. 61.104
  libavdevice    54.  3.103 / 54.  3.103
  libavfilter     3. 35.100 /  3. 35.100
  libswscale      2.  2.100 /  2.  2.100
  libswresample   0. 17.102 /  0. 17.102
  libpostproc    52.  2.100 / 52.  2.100
[mjpeg @ 0x30eb560] Estimating duration from bitrate, this may be inaccurate
Input #0, mjpeg, from 'Video':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: mjpeg, yuvj422p, 926x520 [SAR 1:1 DAR 463:260], 25 fps, 25 tbr, 1200k tbn, 25 tbc
At least one output file must be specified

[cehoyos]

Sample uploaded to  http://samples.ffmpeg.org/ffmpeg-bugs/trac/ticket2222/

[compn]

whats ffmpeg output say when you try encoding it?