Timestamp of thumbnail in video

[dieterdanger]

Hello everyone, is it possible to set a default timestamp in seconds (or 0.5 * video length respectively) for preview generation of videos? I have multiple videos where there is either a black thumbnail or a logo with the default settings.

I've tried to configure Nextcloud to use a bash wrapper-script instead of the ffmpeg binary but I can't get it to work.

Any help highly appreciated :-)

Best regards Dennis