Using mp3 in the application as content. How about a license?

Question

Content

Guys, please explain who knows:
- there is an application on the network aimed at profit - how monetization will be carried out - it is not known. The "content" of the application is a picture + mp3 file uploaded by the user. In general, applications for listening to music.
- there is a law of the Russian Federation that allows you to use 30 seconds of music for free without the copyright holder being able to say: "Where is my share?"

It was then that I had some misunderstandings:
- explain under which license COUB or Zaitsev.net operates. On their portals you can listen to MP3
fragments in their entirety, do they really unfasten the rent to each copyright holder?
Or does it work somehow differently?

I would be glad if you throw links to the info or describe the situation as you know.
Thanks in advance!

Answer 1

elsi briefly - it is impossible to agree with the Four ; - and here they drove ... - but they did not see! ..