Show existing BPM and option to update or not
The program is excellent for occasional use, but the workflow gets a bit messy if you want to analyse a big library. Note that if the file has an existing BPM value, it's not necessarily correct. And the BPM calculated by this program may be better or worse than the one that was there before. So you need to work carefully, comparing the results track by track.
I have a suggestion that would make this much easier. The analysis window could have an extra column to show the previous BPM in the file as well as the newly measured value. Plus a checkbox to say whether you want to update it or not. Then you could update only the ones you believed to be more accurate.
At present, if you analyse 50 songs you have to write all 50 results, even if some are obviously wrong. Hope this helps.
This would fit in nicely with some of the other suggestions. As always, pull requests are welcome.
I'd love to help, but I don't have the required coding skills. Good luck.