An information processing apparatus/method allows a user to interactively combine a plurality of sound chips into music data, edit music data, and play it back, by inputting data or commands via a keyboard or a mouse. A chip such as a sound pattern, a one-shot patter, or an effect to be applied to a sound pattern or a one-shot pattern is assigned to each key of a keyboard. If a user presses a key, a chip corresponding to a pressed key is executed. When a plurality of keys are simultaneously pressed, corresponding chips are played in a superimposed fashion. A piece of music can be composed by sequentially pressing various keys thereby sequentially combining corresponding chips.