MP3 finally goes public domain

Perhaps many did not think about it, but the mp3 standard, so well known to everyone, had problems with patent clearance. On April 23, 2017, the latest patents expired and the format became finally free. Technicolor has officially stopped licensing fees from software manufacturers and embedded solutions.

Licensing

Despite the fact that mp3 hardware decoding is built into every second coffee maker, until recently its use in commercial projects required license fees in favor of the developer - Fraunhofer Society. Only in 2005, the amount of deductions amounted to one hundred million euros. Most patents lost their power in the European Union back in 2012. However, some of them still continued to operate in the United States due to the peculiarities of local legislation. What does this news give to the community? At least now it will be possible to compile Gentoo and listen to music simultaneously at once in the base distribution. Many distributions will be able to transfer support for the standard to the main repository. Now, for example, the same Ubuntu requires the installation of non-free components from a separate ubuntu-restricted-extras meta package to support mp3.

Bourbon Vanilla vs. Vanillin

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How does this standard work, which has been major in this field for 24 years, despite the many more advanced free options? mp3 is very similar in its principles with its fellow from the world of photos - JPEG. Due to the imperfection of our hearing aid and the peculiarities of psychoacoustics, it is possible to “throw out” those parts of the audio spectrum that do not make a significant contribution to the musical pattern. In particular, in the illustration above you can see how the amount of coded information increases in the high-frequency region.

Often, high frequencies are sacrificed for the sake of maintaining detail in a lower region — vocals, most of the instruments (thanks for the comment by KorDen32 ). The standard values ​​of the cutoff frequency at the lame encoder:

CBR 096 kbps: 14000 - 15000 Hz;
CBR 112 kbps: 15000 - 15600 Hz;
CBR 128 kbps: 16000 - 16500 Hz;
CBR 160 kbps: 16500 - 17500 Hz;
CBR 192 kbps: 18000 - 18700 Hz;
CBR 224 kbps: 19000 - 19400 Hz;
CBR 256 kbps: 19500 - 19700 Hz;
CBR 320 kbps: 20000 - 21000 Hz.



The method can be compared with the work of flavor chemists. You probably noticed that strawberry chewing gum is very conditionally strawberry, and in synthetic lemon tea there is not enough citricity. In any natural flavor composition there are dozens and even hundreds of chemical compounds. But the main core usually creates only a very limited amount. So, for example, vanillin determines most of the aroma of natural vanilla, and if you don’t appreciate the subtle nuances too much, the remaining components can be neglected. mp3 uses the same principles, cutting out little significant parts of the spectrum. Most people are not able to distinguish lossless formats by hearing from a normally encoded 320 kbps mp3, which saves a lot of space when storing their music library.