---
https://yunyinyue.iiilab.com/

ffmpeg -i input-video.avi -vn -acodec copy output-audio.aac
or
ffmpeg -i input-video.avi -ss 00:03:05 -t 00:00:45.0 -q:a 0 -map a output-audio.aac.mp3

<?php

chdir('/home/silas/Videos');

$files = glob('*.mp4');
foreach ($files as $file) {
$name = str_replace('.mp4',
'', $file);
$ad = $name. '.aac';
if (!file_exists($ad)) {
echo shell_exec('ffmpeg -i "'. $file .'" -vn -acodec copy "'. $name .'.aac"');
}
}
---