Under the cover :

So, when is the Beatlock performed?

When you load new songs, these are immediately analysed in the background. It could be a good idea, though, on a small machine (for example a Pentium 200 Mhz) NOT to start playing those songs immediately. You may wait until Beatlocking is completed.

Experience teaches that Beatlock analysis lasts about same time as playing on a P200 computer. (i.e. in case of a successful analysis, otherwise it is much longer. )

You may turn off the Beatlocking if you think you do not need it. You may go to the Action->Stop Beatlocking menu to stop the current Beatlocking. You may also turn the 'Do beatlock analysis on songs' off in the global options dialog before you actually load songs.

DJ Mix Lite does not cache the Beatlocking results in files.
But DJ Mix Pro does it, so that it does not need to carry out any further, repetitive computing in the future. This is a nice feature, all the more that such files are really small (about 4K per song) while Beatlocking is CPU heavy.

You may actually see details about the Beatlocking process in the song list. Column 2 shows the BPMs when Beatlock is completed. There are other symbols for other Beatlock statuses :

...	doing Beatlock analysis
---	song does not use Beatlock analysis
BAD	song failed to be Beatlock analysed
???	song not analysed yet

Also, in the song properties dialog, in the Beatlock status field, you may see the song Beatlock status.