To generate an IG stream when converting a format.

A pre-conversion data acquisition part 101 acquires the data of a first format, and a first thumbnail extracting part 102 acquires or generates a thumbnail. A mark extracting part 103 acquires the information of a mark and a second thumbnail extracting part 104 extracts frame image data, corresponding to the mark. An IG generation part 105 generates the IG stream for displaying a menu image, on the basis of the supplied thumbnail and an IG stream registration processing part 106 registers the IG stream to the data of a second format. A command processing part 107 embeds a command for reproducing contents from a prescribed position in the thumbnail. A play list generating part 108 generates a play list for reproducing a title for which IG is registered. A post-conversion data output part 109 outputs the converted data of the second format. The present invention is applicable to a video processor.