concat outputs only the first file

[xamarin]

Summary of the bug:
I try to concatenate 3 videos, but the resulting video is just the first one. The other 2 are missing.

How to reproduce: see the 4 attached files.

% .\ffmpeg.exe -y -i "concat:./part1.mp4|./part2.mp4|./part3.mp4|" -c copy out.mp4
ffmpeg version N-89395-g71421f382f Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 7.2.0 (GCC)
  configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
  libavutil      56.  5.100 / 56.  5.100
  libavcodec     58.  6.102 / 58.  6.102
  libavformat    58.  2.103 / 58.  2.103
  libavdevice    58.  0.100 / 58.  0.100
  libavfilter     7.  6.100 /  7.  6.100
  libswscale      5.  0.101 /  5.  0.101
  libswresample   3.  0.101 /  3.  0.101
  libpostproc    55.  0.100 / 55.  0.100
Hyper fast Audio and Video encoder
usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.

[Carl Eugen Hoyos]

It is not possible to concatenate mp4 files, this is not a limitation of FFmpeg. Use the concat demuxer or the concat filter.
For future tickets: Please remember to provide both the command line you tested and the complete, uncut console output.

[xamarin]

So it's not possible to use the concat protocol with MP4 files. That's the point.

[llogan]

It is not possible to simply physically concat MP4 on a file level such as by using the concat protocol and expect it to work.

From the FAQ regarding the concat protocol:

A few multimedia containers (MPEG-1, MPEG-2 PS, DV) allow one to concatenate video by merely concatenating the files containing them.

As Carl said, use the concat demuxer or concat filter instead for your MP4 inputs.