What is the difference between libavcodec56 libavcodec57 libavcodec58?

Question

linux

Explain what is the difference between these libraries and which one should be installed?
My goal is to install audio/video decoders in Linux so that I can play local audio/video files of various formats, as well as any multimedia content on the Internet.
I can't figure out what I need. Is it necessary to install all three libraries, or is one enough? libavcodec58 is the latest version and libavcodec56 libavcodec57 are just used for legacy software or not?
In addition, ffmpeg has a bunch of libraries (perhaps the list is not complete):
libavdevice, libavformat, libavfilter, libavutil, libx264, libx265, libxvidcore,
and each is also represented by several options. Are they really needed or not?

Answer 1

58-57-56 - different versions of libraries.
Those libraries that are explicitly set as dependencies are needed for sure.
Those that are not in the dependencies can be useful for different formats - like libx264 for h264