MP3 is a lossy format, meaning it discards some audio data to reduce file size. At 128 kbps, the file is about 90% smaller than its uncompressed WAV counterpart.
If you need to generate or change a file to this specific bitrate, you can use several methods: How to Save a File in Audacity as an MP3 - Swell AI 128kbps mp3(2.77 MB)
An MP3 file encoded at (kilobits per second) with a file size of 2.77 MB contains approximately 3 minutes and 1 second of audio. MP3 is a lossy format, meaning it discards