> It's something I'd have to think about further and would surely require a case-by-case analysis.

The courts agree with you completely. The Supreme Court ruling Campbell v. Acuff-Rose Music says that any such analysis must include four factors: if it's commercial/non-commercial, the nature of the copied work, the amount copied, and the effect of the copy on the market for the original work.

Parody requires that the original music be somehow recognizable, so the courts disagree with your "do I recognize the sample" test.

The "catchy tune" example you gave may be a violation of copyright, or it may be fair use. For example, if the original song was from the 1970s, with a current market of 20 iTunes+Amazon+whatever sales per year, and the new song comes out making 1 million sales, then it's fair to say that the new song did not greatly affect the primary market. A full analysis would need to cover at least those three other factors as well.

I don't know anything about the Kanye West / Daft Punk / Edwin Birdsong example. I follow so little of modern music. I've certainly read more copyright cases than I've heard songs from all three of those composers combined.

More classically, consider Ella Fitzgerald's famous and lovely scat version of the song "How High the Moon", in which she quotes from other popular songs, including "The Peanut Vendor", "Heat Wave", "A-Tisket, A-Tasket", and "Smoke Gets in Your Eyes". These are music samples, which include the catchy hook from those songs, but where I think anyone would agree there was no market confusion.

I do not know how copyright issues were settled for that recording, nor in live performances (in jazz improvisation, the artist make things up on the spot; how then would all the original artists get paid?). However, it was before Grand Upright Music, Ltd. v. Warner Bros. Records Inc. , which is the court case that established that samples were under copyright law. During Fitzgerald's time her use was likely "accepted practice and such copyright considerations as these were viewed as largely irrelevant." (Quoting http://en.wikipedia.org/wiki/Fair_use )

We had a very vibrant music industry before Grand Upright Music v. Warner Bros, and it allowed genres like scat which incorporated snippets of other copyrighted material. However, do note that that Fitzgerald wasn't "sampling." There are different copyrights for the lyrics, the music, and the musicians, and sampling covers recordings. This is why some hip hop artists use "interpolation" - replaying the music but with different instruments, and only paying the songwriter and not the artist or label. It may sound very similar, but it's not the same and so not covered by the "sound recording" definition used in Bridgeport Music, Inc. v. Dimension Films.

I am not so versed in music copyright at software and written works, and didn't learn about interpolation until just now. When you say "sampling", do you also mean to include interpolation?

BTW, I see you use the term "stolen." The better term is "infringed." Copyright is a limited monopoly protection which expires, and so far copyright violations are part of civil law rather than criminal. While "stolen" has connotations of property rights and criminal law. Using the concept "stolen" may lead to incorrect assumptions when some concepts are incorrectly transferred.