DCP-o-matic is erroring when trying to open a particular MP4 file.

In the GUI, it says: Error: Could not open /path/to/file.mp4. Logfile includes:

Sat  7 Dec 21:24:53 2019: FFmpeg: error reading header
Sat  7 Dec 21:24:53 2019: ERROR: Error in job: Could not open /path/to/file.mp4 (DCP-o-matic could not open the file /path/to/file.mp4 (could not open file /path/to/file.mp4 for reading (-1)).  Perhaps it does not exist or is in an unexpected format.)

If I run the file through FFMPEG in stream copy mode ffmpeg -i file.mp4 -c:v copy -c:a copy out.mp4, the file created by FFMPEG does open in DCP-o-matic correctly. So I guess it's something in the file headers which is causing the problem.

ffprobe output for the file:

ffprobe version 4.2.1 Copyright (c) 2007-2019 the FFmpeg developers
  built with Apple clang version 11.0.0 (clang-1100.0.33.8)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.1_2 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags='-I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include -I/Library/Java/JavaVirtualMachines/adoptopenjdk-13.jdk/Contents/Home/include/darwin -fno-stack-check' --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/path/to/file.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 0
    compatible_brands: mp42mp41
    creation_time   : 2019-04-26T08:28:01.000000Z
  Duration: 00:15:43.08, start: 0.000000, bitrate: 30354 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 2048x1228, 30032 kb/s, 24 fps, 24 tbr, 24k tbn, 48 tbc (default)
    Metadata:
      creation_time   : 2019-04-26T08:28:01.000000Z
      handler_name    : ?Mainconcept Video Media Handler
      encoder         : AVC Coding
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 317 kb/s (default)
    Metadata:
      creation_time   : 2019-04-26T08:28:01.000000Z
      handler_name    : #Mainconcept MP4 Sound Media Handler

Carl, I'll email you the offending file and the DOM project.