что такое booty mix? это типо mash-up?

одно и то же

http://www.lastfm.ru/tag/bootleg
http://www.lastfm.ru/tag/mashup

Мэшап (иначе «мэш-ап» , от англ. mash-up — «смешивать» ) — неоригинальное музыкальное произведение, состоящее, как правило, из двух (реже нескольких) исходных произведений, записанное в студийных условиях путем наложения вокальной партии одного исходного произведения (акапелла) на музыку другого. [1]
http://ru.wikipedia.org/wiki/Мэшап_(музыка)

A mashup (also mesh, mash up, mash-up, blend, bootleg[1] and bastard pop/rock) is a song or composition created by blending two or more pre-recorded songs, usually by overlaying the vocal track of one song seamlessly over the instrumental track of another.[2] To the extent that such works are "transformative" of original content, they may find protection from copyright claims under the "fair use" doctrine of copyright law.[3]

Synonyms

Mashups are known by a number of different names:
Bootlegs (mostly in Europe)
Boots (but not Booty which is a branch of Electro)
Mash-ups
Mashed hits
Smashups (or Smash-Ups)
Bastard pop (as in the combined songs are unofficial; this term is rarely used any more)
Blends
Cutups (or cut ups, a term originally coined by William S. Burroughs to describe some of his literary experiments that involved literally "cutting up" different texts and rearranging the pieces to create a new piece.)
Powermixing (usually the pace has to be speeded up to allow for more song to be played and thus cannot play any single blend for the full length of the song)
Crossovers, but it is in a form of mashup, or version vs. version.

In addition, more traditional terms such as "edits" or (unauthorized) "remixes" are favored by many "bootleggers" (also known as 'leggers).[citation needed]
http://en.wikipedia.org/wiki/Mashup_(music)