ffmpeg -i intro_640x960.mp4 -i 2J0L1PArsqV.mp4 \
-filter_complex '[0:0] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a]' \
-map '[v]' -map '[a]' output.mp4




ffmpeg version 2.1.3 Copyright (c) 2000-2013 the FFmpeg developers
  built on Feb  3 2014 17:50:43 with Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/2.1.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-nonfree --enable-hardcoded-tables --enable-avresample --enable-vda --cc=clang --host-cflags= --host-ldflags= --enable-libx264 --enable-libfaac --enable-libmp3lame --enable-libxvid --enable-libfdk-aac
  libavutil      52. 48.101 / 52. 48.101
  libavcodec     55. 39.101 / 55. 39.101
  libavformat    55. 19.104 / 55. 19.104
  libavdevice    55.  5.100 / 55.  5.100
  libavfilter     3. 90.100 /  3. 90.100
  libavresample   1.  1.  0 /  1.  1.  0
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
  libpostproc    52.  3.100 / 52.  3.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'intro_640x960.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: mp42avc1
    creation_time   : 2014-01-28 20:04:42
  Duration: 00:00:02.00, start: 0.000000, bitrate: 2171 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m), 640x960, 2165 kb/s, 24 fps, 24 tbr, 600 tbn, 1200 tbc (default)
    Metadata:
      creation_time   : 2014-01-28 20:04:42
      handler_name    : Apple Video Media Handler
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from '2J0L1PArsqV.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: mp41mp42isom
    creation_time   : 2013-12-03 18:25:27
  Duration: 00:01:11.43, start: 0.000000, bitrate: 1354 kb/s
    Stream #1:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 640x960, 1287 kb/s, 28.48 fps, 60 tbr, 600 tbn, 1200 tbc (default)
    Metadata:
      creation_time   : 2013-12-03 18:25:27
      handler_name    : Core Media Video
    Stream #1:1(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 62 kb/s (default)
    Metadata:
      creation_time   : 2013-12-03 18:25:27
      handler_name    : Core Media Audio
Stream specifier ':0' in filtergraph description [0:0] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a] matches no streams.