How to extend video formats from ffmpeg library?

Question

PHP

There is a web application that converts video to gif animation using the ffmpeg library, but the functionality of this application is limited to only one format of the uploaded avi video file. I would like to know how to expand the video formats of this application?
There is an array with data:
static private $ext = array('avi', 'jpg', 'jpeg', 'png', 'gif', 'doc', 'docx', 'xls', 'xlsx', 'rar ', 'zip', 'pdf', 'txt', 'rtf');
If you add formats, it will download videos of a certain format, but no conversion will take place.
$log = shell_exec("C:/ffmpeg/bin/ffmpeg.exe -i $inPath $outPath 2>&1");

Answer 1

First - how are you going to convert at least something other than avi to gif from those formats that you specified in the array ???
Second, ffmpeg itself is only limited by the codecs that are installed on the system.