Modify PHP Script

I need some modifications on this script [login to view URL] Modification shoube be on Import-video page , in this page i can import videos from youtube and other sites but the script support only thumbnail upload or it gets fetched automaticly from the source (youtube or other) but i want other option than that .. a field to place a direct image link from exernal site, so i wanna be able to put custom thumbnail link (image should not be downloaded to the server) second thing i need on the same page there is video description , i want other field like that for posting some extra info , this info will include some text and html tags and it should be displayed under the titel (in the video page when you click it to watch it), this field will need new row in the database for storing this info the new field should be safe from XSS does'nt accept unsafe tags like <script> .. you should write files name/location that got modified. please try to follow author style for coding the script ! thats all i wille provide you the script . you need a good knowldege in php, jquery, json !