F:\>c:ffmpeg -i e:\test.264 -vcodec copy e:\test.mkv
ffmpeg version N-78843-g1c7e2cf Copyright (c) 2000-2016 the FFmpeg developers
  built with gcc 5.3.0 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnu
tls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libdcadec --enable-libfreetype --enable-libgme --enab
le-libgsm --enable-libilbc --enable-libmodplug --enable-libmfx --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libo
penjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-
libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-
libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  libavutil      55. 19.100 / 55. 19.100
  libavcodec     57. 27.101 / 57. 27.101
  libavformat    57. 27.100 / 57. 27.100
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 37.100 /  6. 37.100
  libswscale      4.  0.100 /  4.  0.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, h264, from 'e:\test.264':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: h264 (High), yuv420p, 1280x720, 50 fps, 50 tbr, 1200k tbn, 100 tbc
File 'e:\test.mkv' already exists. Overwrite ? [y/N] y
Output #0, matroska, to 'e:\test.mkv':
  Metadata:
    encoder         : Lavf57.27.100
    Stream #0:0: Video: h264 (H264 / 0x34363248), yuv420p, 1280x720, q=2-31, 50 fps, 50 tbr, 1k tbn, 1200k tbc
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
[matroska @ 0000001e1e4a3200] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to
set the timestamps properly
[matroska @ 0000001e1e4a3200] Can't write packet with unknown timestamp
av_interleaved_write_frame(): Invalid argument
frame=    1 fps=0.0 q=-1.0 Lsize=       1kB time=-00:00:00.04 bitrate=N/A speed=N/A
video:225kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown
Conversion failed!