What synthesis method does Structured Audio use for music synthesis?
MPEG-4 does not standardize a synthesis method, but a signal-processing language for describing synthesis methods. Using this language, any current or future synthesis method may be described by a content provider and included in the bitstream. This language is entirely normative and standardized, so that every piece of synthetic music will sound exactly the same on every compliant MPEG-4 decoder, which is an improvement over the great variety in MIDI-based synthesis systems.
