A method comprising: receiving a portion of an audio signal at a first classifier; classifying the portion of the audio signal at the first classifier as speech or as music; and processing the portion of the audio signal, wherein processing the portion of the audio signal comprises: if the portion is classified by the first classifier as speech, then encoding the speech using a first coding mode; or if the portion is classified by the first classifier as music, then: providing the portion to a second classifier; classifying the portion at the second classifier as speech or as music; and encoding the portion of the audio signal, wherein encoding the portion of the audio signal comprises: if the portion is classified at the second classifier as speech, then encoding the portion using a second coding mode; or if the portion is classified at the second classifier as music, then encoding the portion using a third coding mode. receiving a portion of an audio signal at a first classifier; classifying the portion of the audio signal at the first classifier as speech or as music; and processing the portion of the audio signal, wherein processing the portion of the audio signal comprises: if the portion is classified by the first classifier as speech, then encoding the speech using a first coding mode; or if the portion is classified by the first classifier as music, then: providing the portion to a second classifier; classifying the portion at the second classifier as speech or as music; and encoding the portion of the audio signal, wherein encoding the portion of the audio signal comprises: if the portion is classified at the second classifier as speech, then encoding the portion using a second coding mode; or if the portion is classified at the second classifier as music, then encoding the portion using a third coding mode. if the portion is classified by the first classifier as speech, then encoding the speech using a first coding mode; or if the portion is classified by the first classifier as music, then: providing the portion to a second classifier; classifying the portion at the second classifier as speech or as music; and encoding the portion of the audio signal, wherein encoding the portion of the audio signal comprises: if the portion is classified at the second classifier as speech, then encoding the portion using a second coding mode; or if the portion is classified at the second classifier as music, then encoding the portion using a third coding mode. providing the portion to a second classifier; classifying the portion at the second classifier as speech or as music; and encoding the portion of the audio signal, wherein encoding the portion of the audio signal comprises: if the portion is classified at the second classifier as speech, then encoding the portion using a second coding mode; or if the portion is classified at the second classifier as music, then encoding the portion using a third coding mode. if the portion is classified at the second classifier as speech, then encoding the portion using a second coding mode; or if the portion is classified at the second classifier as music, then encoding the portion using a third coding mode.