Intensity depends a lot on how the track was mastered. It's looking mainly at variations in volume. The idea is that intense music never lets up whereas less intense music has passages of loud intermingled with passages that are less loud.
Mastering seems to be the key. Here's an interesting article
http://www.prorec.com/prorec/articles.nsf/files/8A133F52D0FD71AB86256C2E005DAF1CNote how the waveforms get more bunched up between tracks of the same artist over the years. i would imagine this happens in a lot of music and could likely throw of the intensity measurements in MC. IN the sense that the dynamic range that MC uses to calculate intenisty is being reduced.
it seems that the more recent music might not give accurate intensity values since there is a trend to make everything sound as loud as possible. So i would expect the differences in volume to be smaller.
However older stuff maybe early 90' - mid 90s and before should work. An intersting note to his is that the loudness trend started off in the US quite a few yrs before europe, it seems europe caught on to this only in the late nineties and then could not avoid it despite the opinion of many mastering engineers that this was a bad idea in general.( wont get into that as its hotly debated)
The idea to calculate intenisty is interesting depending on the transisitons in volume, but i think another method to determine intensity might need to be found.
For instance, given the loudness trend.
- any music that is sufficiently loud will get tagged with a lower intensity as it has small diff in loudness but, to a listener would certainly be considered more intense.
- any relatively chilled out music will still have small transitions and will similarly be tagged intense whereas it really isnt.
i personally use genre as well in smartlists to help with this. But the promise of MC to me is to be able to detect these sorts of things automatically rather than manually.
BPMs detection is a good start and hope there will be more ideas thrown into MC to help with this.
comments anyone ?