Ephemeral rule - no clue.

Synchronization licence is still needed and an example would be best: Chris writes a song; Chris assigns the copyrights to a publisher as part of a publishing deal; the publisher is zeroed out; you copy Chris's work; Chris sues you; You and Chris go to court; Chris proves that he is the original owner of the work (as there is no publisher to stand against him); Chris wins the case.

Song can generate income:

Record deal - monies paid by the record company to the artist/songwriter.

Mechanical copyrights - paid by the record company to the songwriter for the right to copy his/her work (ie, pressing albums)

Performance copyrights - paid by public bodies (Radio stations, pubs, or any body that plays music in public/ to the public) to the songwriter.

Performance copyrights - paid by the same public bodies to the performer (this, as far as I know does not happen in practice to some extent).

Other than that:
Synchronization fee
Printed music
DART monies
and few more...

Copyrights wise, a song has two components - composition (melody) and lyrics.

Hope this helps...

e·phem·er·al (ĭ-fĕm'ər-əl)
adj.
Lasting for a markedly brief time: “There remain some truths too ephemeral to be captured in the cold pages of a court transcript” (Irving R. Kaufman).
Living or lasting only for a day, as certain plants or insects do.
n.
A markedly short-lived thing.

[From Greek ephēmeros : ep-, epi-, epi- + hēmerā, day.]

e·phem'er·al'i·ty or e·phem'er·al·ness n.
e·phem'er·al·ly adv.

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The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2004, 2000 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

Technologyephemeral
Temporary. Fleeting. Transitory.

“Ephemeral electronic communication” refers to telephone conversations, text messages, chatroom sessions, streaming audio, streaming video, and other electronic forms of communication the evidence of which is not recorded or retained.

The Copyright Office of the Library of Congress is announcing
final regulations that set rates and terms for the public performance
of a sound recording made pursuant to a statutory license by means of
certain eligible nonsubscription transmissions and digital
transmissions made by a new type of subscription service. The final
rule also announces rates and terms for the making of related ephemeral
recordings. The rates and terms are for the 2003 and 2004 statutory
licensing period, except in the case of a new subscription service, in
which case the license period runs from 1998 through 2004.

More info at http://www.copyright.gov/fedreg/2004/69fr5693.html

-TOM-