320kbps is the highest bit rate of mp3. Of course, there is audio with higher bit rates. Many music platforms now call it "lossless", and the format wav or flac has a higher bit rate, which can reach 1200~1400kbps.

However, for ordinary people, it is actually difficult to hear the difference between 256kbps mp3 and lossless. The difference may be due to different hearing abilities of ordinary people, or it may be simply a psychological effect.