Drop frame is only allowed with multiples of 30000/1001 FPS?

[marcorocchini]

Hi please can help a cat?

I try

ffmpeg.exe -threads 12 -y -i input.avi -c:v copy -an out.mxf

but

ffmpeg version 8.0-full_build-www.gyan.dev Copyright (c) 2000-2025 the FFmpeg developers
  built with gcc 15.2.0 (Rev8, Built by MSYS2 project)
  configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-lcms2 --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-libsnappy --enable-zlib --enable-librist --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-libbluray --enable-libcaca --enable-libdvdnav --enable-libdvdread --enable-sdl2 --enable-libaribb24 --enable-libaribcaption --enable-libdav1d --enable-libdavs2 --enable-libopenjpeg --enable-libquirc --enable-libuavs3d --enable-libxevd --enable-libzvbi --enable-liboapv --enable-libqrencode --enable-librav1e --enable-libsvtav1 --enable-libvvenc --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs2 --enable-libxeve --enable-libxvid --enable-libaom --enable-libjxl --enable-libvpx --enable-mediafoundation --enable-libass --enable-frei0r --enable-libfreetype --enable-libfribidi --enable-libharfbuzz --enable-liblensfun --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-dxva2 --enable-d3d11va --enable-d3d12va --enable-ffnvcodec --enable-libvpl --enable-nvdec --enable-nvenc --enable-vaapi --enable-libshaderc --enable-vulkan --enable-libplacebo --enable-opencl --enable-libcdio --enable-openal --enable-libgme --enable-libmodplug --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libshine --enable-libtheora --enable-libtwolame --enable-libvo-amrwbenc --enable-libcodec2 --enable-libilbc --enable-libgsm --enable-liblc3 --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-ladspa --enable-libbs2b --enable-libflite --enable-libmysofa --enable-librubberband --enable-libsoxr --enable-chromaprint --enable-whisper
  libavutil      60.  8.100 / 60.  8.100
  libavcodec     62. 11.100 / 62. 11.100
  libavformat    62.  3.100 / 62.  3.100
  libavdevice    62.  1.100 / 62.  1.100
  libavfilter    11.  4.100 / 11.  4.100
  libswscale      9.  1.100 /  9.  1.100
  libswresample   6.  1.100 /  6.  1.100
Input #0, avi, from 'input.avi':
  Metadata:
    timecode        : 21:57:57;01
  Duration: 00:00:39.20, start: 0.000000, bitrate: 12300 kb/s
  Stream #0:0: Video: h264 (High 4:2:2) (h264 / 0x34363268), yuv422p(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], 12295 kb/s, 50 fps, 50 tbr, 50 tbn
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
[mxf @ 0000024abf27ec40] Drop frame is only allowed with multiples of 30000/1001 FPS
[out#0/mxf @ 0000024abeca6e40] Could not write header (incorrect codec parameters ?): Invalid argument
Conversion failed!

why the error "Drop frame is only allowed with multiples of 30000/1001 FPS" ?

[hello_hello]

Input #0, avi, from 'input.avi':
  Metadata:
    timecode        : 21:57:57;01

It looks like drop frame timecode, and it shouldn't/can't be used for anything other than multiples of an NTSC frame rate, but I have no idea where it came from. Can AVIs store SMPTE timecode??
I assume ffmpeg is copying the timecodes along with the video and it's not happy because the frame rate is 50fps, but I'm kinda guessing.