you fail to mention "why" you're wanting this bpm information...as further guidance may be given. 2 + 2 = 4....but not if you're a farmer looking for subsidies on a farm going broke. If you want the BPM info to auto-classify music genera, then it may be only 50% or 75% effective. give us more clues.
the hardest line to type correctly is: stty erase ^H