Abstract: The Procedure executing unit 42 makes a judgment on which among three conditions are satisfied by each of a plurality of audio streams. The BD-ROM reproduction apparatus selects an audio stream to be reproduced in accordance with each combination of conditions that are satisfied by each audio stream. One of the conditions is that a channel attribute of an audio stream is surround and the reproduction apparatus is capable to output surround audio. If the audio stream to be reproduced conforms to an encoding method such as DTS-HD or DD/DD+ whose audio frames are composed of basic data and extended data, the judgment on whether the surround output is available is made by judging whether or not the reproduction apparatus has a capability to process the extended data.

Abstract: An Interactive Graphics Decoder 13 decodes a graphics stream, and overlays a Page including a plurality of Buttons on a moving picture. The Interactive Graphics Decoder 13 then executes a command corresponding to one of the plurality of Buttons on the Page, to thereby perform (1) a control of switching the Page to another Page and (2) a control of specifying a Button to be set in a selected state on the other Page. A judgment is made as to whether a button number of the specified Button is invalid. If the button number is invalid, an alternative value is written in a status register.