[Most of the Information on this page has been taken from the Revision website, which took most of it from the Breakpoint website. This info has aged well!]
On this page we compiled some important information concerning copyright. If you're unsure whether you're violating our rules or not, please read on; the document will first describe the general rules (as dictated by copyright), then describe some exceptions to these rules as allowed by German law. These rules are not only important to us as distributors/hosters of productions released at Revision, they are also meant to ensure that competition is fair (specifically, if productions rely on third-party work, this should be clearly visible to the visitors that do the voting). If this page doesn't answer your questions, feel free to contact us at firstname.lastname@example.org.
THIRD PARTY CONTENT
All content that is used in your production and that wasn't produced by you or anyone else involved in it qualifies as third-party content (content includes not only graphics and sound, but also code). You may use third-party content in your production if its license allows you to - this is the case with several of the creative commons licenses as well as most open source licenses. Some of these licenses may impose additional restrictions (for example, if you use GPLed code, you are required to provide the source code to your production). You may also use third-party content that is not under such a license if (and only if) you have a signed permit by the copyright holder.
You are required to credit all third-party content properly (a note in an info-file and in the "info" field of the entry submission sheet is fine) unless its license explicitly states that you do not have to.
RIGHT TO CITE (ZITATRECHT)
Several important exceptions to German copyright law are granted by the right to cite (Zitatrecht, §51 UrhG). You may not only quote texts, but also music, images and videos/films. The main points are:
The quoted material has to be sourced properly (as mentioned previously, a note in the readme and on the submission form is enough).
Your work has to be copyrightable. This is the case as soon as your production contains a substantial amount of original work; if it doesn't, you're not allowed to submit it as per the general compo rules anyway, so this shouldn't be a problem.
Quotes have to be verbatim and clearly recognizable (though they may be shortened as long as the original message isn't distorted).
The amount of material quoted must be "appropriate for the purpose of the quote" - in general, quoting single phrases (say, 2-3 lines for text/vocals, a few bars for music, <10 seconds for films/movies) should be OK, while quoting whole sections of a longer text (or a complete short text), a whole theme or the complete vocals from a piece of music, or a whole scene from a film/movie generally isn't.
As a part of free speech legislation, satire and parody enjoy substantial freedom in the EU. As long as your work is clearly recognizable as such, you are allowed to use third-party content (including things such as trademarked logos) to a far larger extent than permitted by the previously mentioned Zitatrecht: satire is not required to quote verbatimly (or in a way that preserves the original message), nor are there specific restrictions on the amount of material quoted. In fact, satiric works are nearly unrestricted; the main limitation is that they may not seriously infringe another person's basic rights.
Please consider using one of the creative commons licenses for your works released at onScene, to encourage sharing and remixing.