cat input_test.mp4 | ffmpeg -i input_test.mp4 -i - -filter_complex "[0:v] [0:a] [1:v] [1:a] concat=n=2:v=1:a=1 [v] [a]" -map "[v]" -map "[a]" output_test.mp4
ffmpeg version 3.2.12-1~deb9u1 Copyright (c) 2000-2018 the FFmpeg developers
  built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
  configuration: --prefix=/usr --extra-version='1~deb9u1' --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --disable-stripping --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libebur128 --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmp3lame --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-omx --enable-openal --enable-opengl --enable-sdl2 --enable-libdc1394 --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libopencv --enable-libx264 --enable-shared
  libavutil      55. 34.101 / 55. 34.101
  libavcodec     57. 64.101 / 57. 64.101
  libavformat    57. 56.101 / 57. 56.101
  libavdevice    57.  1.100 / 57.  1.100
  libavfilter     6. 65.100 /  6. 65.100
  libavresample   3.  1.  0 /  3.  1.  0
  libswscale      4.  2.100 /  4.  2.100
  libswresample   2.  3.100 /  2.  3.100
  libpostproc    54.  1.100 / 54.  1.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input_test.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: mp42avc1
    creation_time   : 2011-03-16T10:41:51.000000Z
  Duration: 00:01:00.08, start: 0.000000, bitrate: 699 kb/s
    Stream #0:0(eng): Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709), 640x360, 633 kb/s, 24.04 fps, 24.04 tbr, 2500 tbn, 5k tbc (default)
    Metadata:
      creation_time   : 2011-03-16T10:41:52.000000Z
      handler_name    : Apple Video Media Handler
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 62 kb/s (default)
    Metadata:
      creation_time   : 2011-03-16T10:41:53.000000Z
      handler_name    : Apple Sound Media Handler
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55fc3c8410c0] stream 0, offset 0x28: partial file
[mov,mp4,m4a,3gp,3g2,mj2 @ 0x55fc3c8410c0] Could not find codec parameters for stream 0 (Video: h264 (avc1 / 0x31637661), none, 640x360, 633 kb/s): unspecified pixel format
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'pipe:':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: mp42avc1
    creation_time   : 2011-03-16T10:41:51.000000Z
  Duration: 00:01:00.08, bitrate: N/A
    Stream #1:0(eng): Video: h264 (avc1 / 0x31637661), none, 640x360, 633 kb/s, 24.04 fps, 24.04 tbr, 2500 tbn, 5k tbc (default)
    Metadata:
      creation_time   : 2011-03-16T10:41:52.000000Z
      handler_name    : Apple Video Media Handler
    Stream #1:1(eng): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 62 kb/s (default)
    Metadata:
      creation_time   : 2011-03-16T10:41:53.000000Z
      handler_name    : Apple Sound Media Handler
[buffer @ 0x55fc3c907f80] Unable to parse option value "-1" as pixel format
    Last message repeated 1 times
[buffer @ 0x55fc3c907f80] Error setting option pix_fmt to value -1.
[graph 0 input from stream 1:0 @ 0x55fc3c907e80] Error applying options to the filter.
Error configuring complex filters.
Invalid argument