Sun Apr 10, 2016 5:07 am by talanmawr
For what it's worth...here's a FFMPEG- -i of an MKV file that won't play:
ffmpeg version 2.4.git Copyright (c) 2000-2014 the FFmpeg developers
built on Nov 19 2014 22:12:09 with gcc 4.7.2 (GCC)
configuration: --enable-static --disable-shared --disable-ffplay --disable-ffserver --enable-memalign-hack --enable-libmp3lame --enable-libass --enable-librtmp --enable-fontconfig --enable-libfreetype --enable-zlib --enable-libx264 --enable-libspeex --extra-libs='-lrtmp -lpolarssl -lws2_32 -lwinmm -lexpat -lfreetype -lfribidi -lz' --arch=x86 --enable-runtime-cpudetect --enable-pthreads --target-os=mingw32 --cross-prefix=i686-w64-mingw32- --enable-gpl --pkg-config=pkg-config
libavutil 54. 14.100 / 54. 14.100
libavcodec 56. 12.101 / 56. 12.101
libavformat 56. 14.100 / 56. 14.100
libavdevice 56. 3.100 / 56. 3.100
libavfilter 5. 2.103 / 5. 2.103
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 1.100 / 1. 1.100
libpostproc 53. 3.100 / 53. 3.100
The device just complains that it's not a playable format.