15 seconds of copyrighted music is allowed but adding music
and or sound effects tends to mess with a seamless loop causing
a jerk or a stop and go again.
Non copyrighted music is allowed with no time limits if permission to use is linked
It can be done though , I've done a few.
Posting a link/links in your description when uploading a dream is
easy just copy and paste the URL and it will show up once uploaded
as the word LINK.
Actual dreams loop cleaner than youtube video loops.
Using youtube video in a dream is not allowed on WC but it is OK to use youtube
for your video preview.
One other thing a dream file is best when formatting it to an AVI file
when you can vs. a WMV file ... AVI uses 1/2 the CPU usage then a WMV file.
You can PM me with a private message if you have other dream questions.