This chapter will show you how we can come up with a decent classifier in a domain that is outside our comfort zone. For one, we will have to use sound-based features, which are much more complex than the text-based ones we've used so far. And then we will learn how to deal with more classes than we have tackled before. In addition, we will get to know new ways of measuring classification performance.

Let's assume a scenario where, for some reason, we find a bunch of randomly-named MP3 files on our hard disk, which are assumed to contain music. Our task, to sort them according to music genre into different folders, such as jazz, classical, country, pop, rock, and metal.