A conversion apparatus and method is disclosed by which a file including data multiplexed therein can be edited or handled readily while maintaining the compatibility. A standard/independent conversion section converts a file of a standard AV multiplex format wherein video data and audio data are placed in a multiplexed state in a body into a file of an AV independent format wherein video data or audio data are placed collectively in a body. Meanwhile, an independent/standard conversion section converts a file of the AV independent formation into a file of the standard AV multiplex format.