./ffmpeg -i ../Screen/out.nut -c:v h264 out.mkv
ffmpeg version N-63766-gced5c9b Copyright (c) 2000-2014 the FFmpeg developers
  built on Sep 28 2014 13:34:43 with Apple LLVM version 5.1 (clang-503.0.40) (based on LLVM 3.4svn)
  configuration: --disable-everything --enable-gpl --enable-indev=avfoundation --enable-demuxer=nut --enable-muxer=matroska --enable-protocol=file --enable-encoder=flv --enable-encoder=libx264 --enable-encoder=aac --enable-encoder=libmp3lame --enable-protocol=pipe --enable-protocol=rtmp --enable-libx264 --enable-libmp3lame --extra-ldflags=-L/Users/void/temp/libs/install/lib --extra-cflags=-I/Users/void/temp/libs/install/include
  libavutil      52. 89.100 / 52. 89.100
  libavcodec     55. 66.100 / 55. 66.100
  libavformat    55. 42.101 / 55. 42.101
  libavdevice    55. 13.101 / 55. 13.101
  libavfilter     4.  5.100 /  4.  5.100
  libswscale      2.  6.100 /  2.  6.100
  libswresample   0. 19.100 /  0. 19.100
  libpostproc    52.  3.100 / 52.  3.100
Input #0, nut, from '../Screen/out.nut':
  Metadata:
    encoder         : Lavf56.1.100
  Duration: 00:00:10.15, start: 0.000000, bitrate: 238078 kb/s
    Stream #0:0: Video: rawvideo (UYVY / 0x59565955), 1440x900, 100 tbr, 51200 tbn, 51200 tbc
File 'out.mkv' already exists. Overwrite ? [y/N] y
[buffer @ 0x7f9fd9c10d80] Unable to parse option value "-1" as pixel format
    Last message repeated 1 times
[buffer @ 0x7f9fd9c10d80] Error setting option pix_fmt to value -1.
[graph 0 input from stream 0:0 @ 0x7f9fd9c10e40] Error applying options to the filter.
Error opening filters!