According to productioncounsel.com, the U.S. copyright law contains clauses for "fair use" of copyrighted work for research, comment, analysis, scholarship or criticism purposes. Rules regarding fair use depend on a number of factors, including type of work and manner used. If you include a song in a documentary, for example, that explores a type of music, this may constitute fair use. However, if a narrative film uses a song that a character discusses, this may not be fair use.
Copyright law states that compulsory licensing fees exist for playing copyrighted music in certain venues, like motion pictures. It may cost up to $150,000 or more just to include 30 seconds of a well-known song in your production. Even if you know your budget will allow it, some music owners may still refuse licensing, regardless of dollar amount. Instead of writing a scene including a specific piece of popular music, get licensing first. This saves you the time and money involved in writing and perhaps even shooting and editing a scene that may have to be changed or cut if licensing falls through.
You also have the option of simply not writing copyrighted material into your script. This saves you thousands of dollars on the front end (before your script has even been sold) and actually allows for more artistic collaboration. If you write your script with only general music references, once your script is optioned or sold, you and your production team can decide on music that complements the film's other elements and fits within your budget and resources.
Typically, you must secure two types of licenses to include a copyrighted recording in your film. A synchronization license allows you to sync the recording with your visual image. You secure this through the publisher. Consult ASCAP or the National Music Publishers' Association for information on a song's publisher.
You must also obtain a master use license, which allows you to use a particular recording of a song in your film. You must contact the song's record label for this license. Check the album liner notes or consult ASCAP for a label contact. Soundtrack use must also be negotiated during the sync and master licensing process.
Generally, music more than seventy-five years old falls into the public domain category. This means there are no licensing fees or permissions required to include it in your script. However, note that a particular performance or recording of that piece may be subject to copyright law, unless the recording itself is also over seventy-five years old. Be sure to perform research on any recording you'd like to use before including it. You might also choose to record a version of such a song yourself. This may be simpler and far cheaper than paying licensing fees.