When do the MP3 patents expire?

Why exactly is MP3 still popular? It’s not as efficient as more recent compression methods, and it’s encumbered by patents. People keep using what’s familiar. In a few years, it may become patent-free.

A Tunequest piece from 2007 lists several expiration dates that are still in the future:

• Patent 5,579,430: November 20, 2016
• Patent 5,579,430: November 20, 2016
• Patent 6,185,539: February 19, 2017
• Patent 6,009,399: April 16, 2017
• Patent 5,924,060: August 29, 2017
• Patent 5,703,999: December 30, 2017

The term MP3 covers several related specifications, under MPEG-1 Audio Layer 3 and MPEG-2 Audio Layer III. The MPEG-2 Layer III standard was published in 1995, and US patents don’t last longer than 20 years, so you’d think all patents would have expired by now. However, Patent 5,703,999 was issued on December 30, 1997. Patent terms are sometimes counted from the date of filing and sometimes from the date of issue; either one can be later than the date that the invention or process they describe was first made public.

Licenses to implement MP3 are expensive. Creating a codec costs $2.50 per unit. There’s no minimum distribution for fees to kick in and no exemption for free software. If you implement MP3 in a game, it costs $2,500.

Fraunhofer, which holds the MP3 patents, isn’t saying when they expire; uncertainty works to its advantage. It could assert that other patents, issued later, apply to MP3 in an effort to stretch its control. It may take a court battle to determine for sure when it has fallen into the public domain.