Rapid Evolution contains many features, and therefore can be complicated for new users. One of the more popular features is automatic key and BPM detection. This section is for users who don't want to spend time to learn Rapid Evolution, but merely want to add key and BPM information to their existing song tags.
The simplest way to add songs is to drag and drop the folder/directory containing your music onto Rapid Evolution's search window. This will bring up the “add song(s)” dialog. Here, select “add all” and wait until all the songs have been processed (a dialog summarizing the results will be displayed at the end). You can also import songs directly from a variety of sources.
In the search table, highlight all of your songs (either via CTRL-A or by holding SHIFT), then right/option click and select detect→all (or you could select detect→bpm or detect→key specifically). Wait for this process to finish.
Before writing tags, go under options→song→tag writing and select the fields you wish to be written to the tag (such as just key or BPM). Rapid Evolution supports writing the key to the following fields:
You can write the key info to any other field by first copying the key info into that desired field using right/option click fields→copy.
Finally, to write the key or BPM information to your song tags, highlight all of your songs in the search table, then right/option click and select tags→write. It is safe practice to test this on a few files before processing all of them. If you find that tag writing is incompatible with your setup, you can try one of the other tag libraries provided under options→song→tag writing.