Such adaptation requires additional copyright permission in most nations, even if someone already have permission to distribute the music unaltered.
It's a great comparison on a common sense basis, but could you be more specific? My impression is that in the US there still isn't any definitive "vidding" caselaw. Are you aware of some, or by "most nations" are you referring to the (primarily European) moral rights to the integrity of the work? [1]
Moral rights in EU is used to address a different problem, primarily about the association between the author and his work. For example, political advertisement would need to walk careful when using stock-photos or music repositories, since the integrity of the work could be seen as infringed on. It is normally seen as covered by defamation laws in the US, so its not part of US copyright.
What I am talking about is Synchronization rights[1]. If a musician has a deal with a publisher, they often want to be paid more if the song is played on a TV commercial then if its played on the radio or distributed on a CD. Most of this I just remember reading about years ago, but I remember that creative commons also address this concept[2]. An other example would be the agreement between NMPA and YouTube in 2011, where YouTube was granted the right to "reproduce, distribute and prepare derivative works (including synchronization rights)".
I have not memorized any specific cases where someone challenged this industry practice in court, and digging for one would take a bit more time that I have at the moment.
I see now what you are saying, although I'm not sure if the granularity of licensing affects the legality of the redistribution. But that might be because I've been thinking about it solely in the context of noncommercial areas, where "fair use" rather than licensing is the gauge. Once under "fair use", there is no special treatment of synchronization, and there even exists a specific DMCA exclusion for non-commercial video mashups: https://www.eff.org/files/2015/02/09/2014-07_eff_remix_comme...
It's a great comparison on a common sense basis, but could you be more specific? My impression is that in the US there still isn't any definitive "vidding" caselaw. Are you aware of some, or by "most nations" are you referring to the (primarily European) moral rights to the integrity of the work? [1]
[1] https://meta.wikimedia.org/wiki/Wikilegal/Moral_right_of_int...