After AVAssetExportSession has complete export video. I have plan to garb Video Path to upload via Youtube. but [GDataUtilities MIMETypeForFileAtPath:path def
AVAssetExportSession
[GDataUtilities MIMETypeForFileAtPath:path def
Use this. I think it will help you.
In Objective c
NSString *testString = testUrl.absoluteString;
In Swift
var testString : String = testUrl.absoluteString