A non-numeric value encountered

Thanks for reporting this and providing a patch.

Can you please confirm what are the values of these two variables (variable_get('video_transcode_timeout') and variable_get('video_ffmpeg_instances')) when you get that warning?

I understand that when you use the admin form on admin/config/media/video/scheduling and change the values, then these variables will be strings, but it is not causing any warnings/error on my PHP 8.1 testing enviroment. Only error I can get is when one of these variables is set to the empty string.

If that is the case, then I propose to change the patch and add '#required' => TRUE to each variable settings input field in video_scheduling_admin_settings(). These fields are currently protected via '#element_validate' => array('element_validate_integer_positive'), but this validator will allow an empty string.