After 2 days searching, applying and claiming my money back from several hosters I finally found one with ffmpeg and PHP 5.3
It is HostForWeb
http://www.hostforweb.com/1873.html
It will cost you $6.36 for 1 month when you use promotional code "autumn"
I think it is a good choice for those who want to test their scripts first before applying for more serious hosting.
Script is working properly.