A signal processing apparatus may include a decoder that decodes a compressed audio stream encoded by a predetermined codec, a signal processing unit that applies predetermined signal processing to an audio stream obtained by decoding the compressed audio stream with the decoder, a first acquisition unit that acquires at least one of information described in a header of the compressed audio stream and management information for contents including the compressed audio stream, a setting unit that discriminates, on the basis of the information, a type of the codec used for the encode of the compressed audio stream and sets a codec used for encode of the audio stream, and an encoder that encodes, in accordance with the setting by the setting unit, the audio stream subjected to the signal processing by the signal processing unit and outputs the audio stream to an external apparatus that has a decoder.