ffmpeg version 2.7.2 Copyright (c) 2000-2015 the FFmpeg developers
  built with FreeBSD clang version 3.4.1 (tags/RELEASE_34/dot1-final 208032) 20140512
  configuration: --disable-libaacplus --disable-libopencore-amrnb --disable-libopencore-amrwb --disable-libass --disable-libcdio --disable-libcelt --disable-libfaac --disable-libfdk-aac --enable-ffserver --enable-fontconfig --enable-libfreetype --enable-frei0r --disable-libgsm --enable-iconv --disable-indev=jack --enable-libmp3lame --disable-libbluray --enable-libv4l2 --disable-libmodplug --disable-openal --disable-indev=openal --enable-libopencv --disable-libopenjpeg --disable-libopus --enable-libpulse --disable-librtmp --enable-libschroedinger --disable-libspeex --enable-libtheora --disable-vaapi --enable-vdpau --enable-libvorbis --disable-libvo-aacenc --disable-libvo-amrwbenc --enable-libvpx --enable-libx264 --disable-libx265 --enable-libxvid --enable-gnutls --disable-openssl --prefix=/usr/local --mandir=/usr/local/man --datadir=/usr/local/share/ffmpeg --pkgconfigdir=/usr/local/libdata/pkgconfig --enable-shared --enable-gpl --enable-postproc --enable-avfilter --enable-avresample --enable-pthreads --disable-libstagefright-h264 --disable-libutvideo --disable-libsoxr --cc=cc --extra-cflags='-msse -I/usr/local/include/vorbis -I/usr/local/include' --extra-ldflags='-L/usr/local/lib ' --extra-libs=-lpthread --disable-debug --disable-ffplay --disable-outdev=sdl
  libavutil      54. 27.100 / 54. 27.100
  libavcodec     56. 41.100 / 56. 41.100
  libavformat    56. 36.100 / 56. 36.100
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 16.101 /  5. 16.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.100 /  1.  2.100
  libpostproc    53.  3.100 / 53.  3.100
Guessed Channel Layout for  Input Stream #0.0 : stereo
Input #0, oss, from '/dev/dsp3':
  Duration: N/A, start: 1439910895.059883, bitrate: 1536 kb/s
    Stream #0:0: Audio: pcm_s16le, 48000 Hz, 2 channels, s16, 1536 kb/s
Input #1, video4linux2,v4l2, from '/dev/video0':
  Duration: N/A, start: 1153.640602, bitrate: 147456 kb/s
    Stream #1:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 640x480, 147456 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc
File 'output.mkv' already exists. Overwrite ? [y/N]