What software can massively reduce MP3 bitrate?

Question

MP3

Good afternoon, please advise a simple and free software for converting MP3, more precisely,
there is a folder of different hierarchy inside which there are MP3 files of different bitrates, you just need to
lower the bitrate for all files, for example, to 128kbps with the replacement of the original files.
Those. run once and everything has changed everywhere The
software is preferably with an interface, in order to roughly speaking open, select a folder, select a bitrate - press Start

Answer 1

Try JetAudio. I do not remember what about the folder hierarchy, but within the same folder 100% works.

Answer 2

easy CDDA