I have the same problem with xhamster. Jdownloader grabs some videos ok, but it also grabs some videos as .m3u8 file, which is a playlist format, not a video format. When I try to download that file m3u8 it always download a file that doesn't contain anything.
Here's the screenshot:
http://www.imagevenue.com/MENX2YG
Example link (this one has the problem): **External links are only visible to Support Staff****External links are only visible to Support Staff**
Here's the log: 19.04.20 12.59.29 <--> 19.04.20 18.38.43 jdlog://7558815302851/
I hope you can fix it. Thank you.