Patent ID: 7522819

Claim:
A method of recording data on a storage medium comprising: recording main data in a bitstream on the storage medium, the main data comprising audio data and/or video data; recording sub data, corresponding to the main data, in a bitstream on the storage medium, the bitstream of the sub data being separate from the bitstream of the main data; and recording navigation information on the storage medium, the navigation information defining a relation between the main data and the sub data that enables the sub data to be reproduced in synchronization with the main data; wherein: the navigation information is used to control reproduction of the main data and the sub data; the navigation information comprises: an identifier to identify the bitstream of the main data that corresponds to the sub data and is to be reproduced in synchronization with the sub data; and playback time information for the sub data corresponding to the bitstream of the main data; and the main data, the sub data, and the navigation information are asynchronously recorded.