I answered this once but see it is gone for some reason. maybe I didn't hold my mouth right. I don't really understand the question but I have been downloading since Napster and have an understanding of bitrate. I don't know a formula. And I haven't played Mp3s in years. But I believe 320mbps is 4-5 megs per minute, probably closer to 5. 256kbps in 3.5 megs Flac is 768 I believe. Its been a while and I don't remember the formulas. Hope this helps