No video previews generated

When I'm running occ preview:generate-all -vvv only previews of images and documents are generated, but the mp4 video files are completely ignored.

Generating previews for /user/files/Photos/Birdie.jpg
Generating previews for /user/files/Photos/Frog.jpg
Generating previews for /user/files/Photos/Gorilla.jpg
Generating previews for /user/files/Photos/Library.jpg
Generating previews for /user/files/Photos/Nextcloud community.jpg
Generating previews for /user/files/Photos/Readme.md
Generating previews for /user/files/Photos/Steps.jpg
Generating previews for /user/files/Photos/Toucan.jpg
Generating previews for /user/files/Photos/Vineyard.jpg

My nextcloud config.php looks like this:

  'enabledPreviewProviders' =>
  array (
    0 => 'OC\\Preview\\Movie',
    1 => 'OC\\Preview\\GIF',
    2 => 'OC\\Preview\\JPEG',
    3 => 'OC\\Preview\\MarkDown',
    4 => 'OC\\Preview\\MP3',
    5 => 'OC\\Preview\\PNG',
    6 => 'OC\\Preview\\TXT',
    7 => 'OC\\Preview\\XBitmap',
    8 => 'OC\\Preview\\BMP',
    9 => 'OC\\Preview\\OpenDocument',
    10 => 'OC\\Preview\\Krita',
    11 => 'OC\\Preview\\HEIC',
    12 => 'OC\\Preview\\PDF',
    13 => 'OC\\Preview\\MP4',
    14 => 'OC\\Preview\\MKV',
    15 => 'OC\\Preview\\AVI',
  ),

ffmpeg is installed:

user@host:~$ which ffmpeg
/usr/bin/ffmpeg

user@host:~$ ffmpeg -version
ffmpeg version 4.3.5-0+deb11u1 Copyright (c) 2000-2022 the FFmpeg developers
built with gcc 10 (Debian 10.2.1-6)
configuration: --prefix=/usr --extra-version=0+deb11u1 --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --arch=amd64 --enable-gpl --disable-stripping --enable-avresample --disable-filter=resample --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libcodec2 --enable-libdav1d --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libjack --enable-libmp3lame --enable-libmysofa --enable-libopenjpeg --enable-libopenmpt --enable-libopus --enable-libpulse --enable-librabbitmq --enable-librsvg --enable-librubberband --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxml2 --enable-libxvid --enable-libzmq --enable-libzvbi --enable-lv2 --enable-omx --enable-openal --enable-opencl --enable-opengl --enable-sdl2 --enable-pocketsphinx --enable-libmfx --enable-libdc1394 --enable-libdrm --enable-libiec61883 --enable-chromaprint --enable-frei0r --enable-libx264 --enable-shared
libavutil      56. 51.100 / 56. 51.100
libavcodec     58. 91.100 / 58. 91.100
libavformat    58. 45.100 / 58. 45.100
libavdevice    58. 10.100 / 58. 10.100
libavfilter     7. 85.100 /  7. 85.100
libavresample   4.  0.  0 /  4.  0.  0
libswscale      5.  7.100 /  5.  7.100
libswresample   3.  7.100 /  3.  7.100
libpostproc    55.  7.100 / 55.  7.100

user@host:~$ which ffprobe
/usr/bin/ffprobe

occ memories:index tells me:

MIME Type support:
  image/png: supported
  image/jpeg: supported
  image/heic: supported
  image/png: supported
  image/tiff: not supported
  image/gif: supported
  image/bmp: supported
  image/x-dcraw: not supported
  video/mpeg: not supported
  video/webm: not supported
  video/mp4: not supported
  video/quicktime: not supported
  video/x-matroska: not supported

Nextcloud is installed on a Debian 11 VM with Apache and PHP-FPM 8.1.

What am I missing here?

nextcloud / previewgenerator

No video previews generated #359