[FFmpeg-devel] Problem with "-f concat" and mixed path types on Windows.

[Steinar Apalnes]

Hi,
It looks like the -f concat options has a problem when mixingUNC paths in
the concat file and local concat file path in command line:


Concat file:

ffconcat version 1.0
file '\\server\CanonXF\CONTENTS\CLIPS001\AA4002\AA400201.MXF'
file '\\server\CanonXF\CONTENTS\CLIPS001\AA4002\AA400202.MXF'
file '\\server\CanonXF\CONTENTS\CLIPS001\AA4002\AA400203.MXF'
file '\\server\CanonXF\CONTENTS\CLIPS001\AA4002\AA400204.MXF'
file '\\server\CanonXF\CONTENTS\CLIPS001\AA4002\AA400205.MXF'


Full command:

"D:\FFMpeg\x64\ffmpeg.exe" -f concat -safe 0 -i "d:\temp\AA4002.mxf.concat"
-map 0 -c copy -y "d:\temp\AA4002.mxf"


Full ffmpeg output:

ffmpeg version N-99922-g8b819bcb9e Copyright (c) 2000-2020 the FFmpeg
developers
  built with gcc 10.2.0 (Rev5, Built by MSYS2 project)
  configuration:  --disable-static --enable-shared --cc='ccache gcc'
--cxx='ccache g++' --disable-autodetect --enable-amf --enable-bzlib
--enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-iconv
--enable-lzma --enable-nvenc --enable-zlib --enable-sdl2 --enable-ffnvcodec
--enable-nvdec --enable-cuda-llvm --enable-libmp3lame --enable-libopus
--enable-libvorbis --enable-libx264 --enable-libx265 --enable-libdav1d
--enable-libaom --disable-debug --enable-fontconfig --enable-libass
--enable-libbluray --enable-libfreetype --enable-libmfx --enable-libmysofa
--enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg
--enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora
--enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc
--enable-libwebp --enable-libxml2 --enable-libzimg --enable-libshine
--enable-gpl --enable-avisynth --enable-libxvid --enable-libopenmpt
--enable-version3 --enable-librav1e --enable-libsrt --enable-libgsm
--enable-libvmaf --enable-libsvtav1 --enable-mbedtls
--extra-cflags=-DLIBTWOLAME_STATIC --extra-libs=-lstdc++
--extra-cflags=-DLIBXML_STATIC --extra-libs=-liconv --disable-w32threads
--shlibdir=/local64/bin-video
  libavutil      56. 60.100 / 56. 60.100
  libavcodec     58.112.103 / 58.112.103
  libavformat    58. 64.100 / 58. 64.100
  libavdevice    58. 11.102 / 58. 11.102
  libavfilter     7. 89.100 /  7. 89.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
[concat @ 000001fa3b087f80] Impossible to open
'd:\\server\CanonXF\CONTENTS\CLIPS001\AA4002\AA400201.MXF'
d:\temp\AA4002.mxf.concat: No such file or directory


As you see, it seems for some strange reason that it adds a local "d:"
before the UNC path "\\server\....", which of course will not work. There's
nothing else wrong with the command or concat files cause if I change the
content of the concat file to the local representation of the
\\server\CanonXF share E: it works just fine. Same if the concat file is on
the \\server share. So it seems that concat wants the files in the list to
have the same path type as the concat file itself.

Steinar Apalnes