I create MP3 output from Cubase, and indirectly from Ableton Live, too (by exporting WAV, then letting LANDR process that into a mastered MP3 file). Any chance the BPM value is stored in the MP3 metadata; does anyone know? If it is, can MP3Tag parse the metadata and populate its BPM field with the info?
The BPm is stored in the field BPM.
MP3tag does not do anything with the audio part. It only helps you to enter the value for BPM if you know it.
There was once a program called BPMAnalyzer ... perhaps you find that with an internet search.
Found it for you, it used to be freeware but it's now payware $3.99. Maybe the old version is still somewhere to be found