./transcoding myH264testMovie_original.mp4 myH264testMovie.mkv
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'myH264testMovie_original.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf54.59.106
  Duration: 00:37:21.38, start: 0.023220, bitrate: 4590 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1280x720, 4489 kb/s, 29.97 fps, 29.97 tbr, 11988 tbn, 59.94 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 96 kb/s (default)
    Metadata:
      handler_name    : SoundHandler
[libx264 @ 0x2232480] broken ffmpeg default settings detected
[libx264 @ 0x2232480] use an encoding preset (e.g. -vpre medium)
[libx264 @ 0x2232480] preset usage: -vpre <speed> -vpre <profile>
[libx264 @ 0x2232480] speed presets are listed in x264 --help
[libx264 @ 0x2232480] profile is optional; x264 defaults to high
Cannot open video encoder for stream #0
Error occurred: Operation not permitted