1. An apparatus for classifying an input audio signal into audio contents of a first class and of a second class, the apparatus comprising: an audio segmentation module adapted to segment said input audio signal into one or more of segments of a predetermined length; a feature computation module adapted to calculate for each of said one or more segments one or more features characterizing said audio input signal; a threshold comparison module adapted to generate a feature vector for each of said one or more segments by comparing the one or more features in each segment with a plurality of predetermined thresholds, the plurality of predetermined thresholds including for each of the audio contents of the first class and of the second class a substantially near certainty threshold, a substantially high certainty threshold, and a substantially low certainty threshold, wherein each threshold of the plurality of thresholds represents a statistical measure relating to the one or more features; and a classification module adapted to analyze the feature vector and classify each one of said one or more segments as audio contents of the first class, of the second class, or as non-decisive audio contents; wherein a segment is classified as audio contents of the first class when the feature vector includes at least one feature surpassing the substantially near certainty threshold of the first class and no features surpassing the substantially near certainty threshold and the substantially high certainty threshold of the second class; wherein the classification module is further adapted to, at one or more subsequent intermediate classifications stages, to classify a non-decisive segment as audio contents of the first class when a majority of features in the feature vector surpass the substantially high certainty threshold of the first class and no features surpass the substantially high certainty threshold of the second threshold; and wherein the classification module is further adapted to, at a subsequent separation classifications stage, classify segments of non-decisive audio contents into audio contents of the first class or of the second class.