Selecting previously unselected package libavcodec-ffmpeg56:amd64.
dpkg: regarding .../libavcodec-ffmpeg56_7%3a2.7.2-1build1_amd64.deb containing libavcodec-ffmpeg56:amd64:
 libavcodec-ffmpeg-extra56:amd64 conflicts with libavcodec-ffmpeg56
  libavcodec-ffmpeg56:amd64 (version 7:2.7.2-1build1) is to be installed.

dpkg: error processing archive /var/cache/apt/archives/libavcodec-ffmpeg56_7%3a2.7.2-1build1_amd64.deb (--unpack):
 conflicting packages - not installing libavcodec-ffmpeg56:amd64