exec() with SuPHP and SafeMode Off (php.ini local) show wrong path and fail execution

Question

Try this

<?php
     if (exec('/usr/bin/ffmpeg -i 47.mp4 -acodec aac -ab 128kb -vcodec mpeg4 -b 1220kb -mbd 1 -s 320x180 final_video.mov"'))
         { echo "Success"; }
     else { echo "No good"; }
?>

But on shell see-->

sh: /usr/local/php/bin/ffmpeg: No such file or directory

Server it's Apache+SuPHP with a local php.ini file for disable SafeMode

I don't understand why show sh: /usr/local/php/bin/ffmpeg: No such file or directory instead real path put on php script.