Unable to upload video file size >=500MB. using PHP-ffmpeg

Unable to upload video file size more than 500MB. using FFmpeg file conversion, The file Uploading procedure works fine, but when it comes to calling a POST request FFmpeg, The conversion doesn't work

I got the error log is like
PHP Fatal error: Uncaught Exception: Movie file not found in /home/wwwquakb/public_html/qb_classes/FFmpeg-php/provider/FFmpegOutputProvider.php:39

If you are good at PHP video file conversion system (FFmpeg) Please bid here
See the video here what happens when I try to upload 1GB file
https://www.loom.com/share/baad97502bc7468c833bf5dcb73a543e?sharedAppSource=personal_library