Recording medium having video data stored therein which is capable of forcibly reproducing sub-picture in accordance with state of reproduction and system for the same

A recording medium (10) is provided in which video data capable of forcibly reproducing a sub-picture in accordance with a state of reproduction is stored. A sub-picture pack sequence (85) for forming a sub-picture data unit (230) stores a unit header, run-length-compressed sub-picture pixel data (232) and a display sequence table (233). The display sequence table (233) stores a plurality of display sequences (234) and having, described therein, a command for forcibly outputting sub-picture pixel data as the display sequence (234).