Reproducing device

A reproducing device for playing back data from a recording medium, including: play back circuits for reading first stream data, which includes first video data, first audio data, and first subpicture data, from a recording medium; download data storage circuits for storing second stream data, which includes at least one of second video data, second audio data and second subpicture data downloaded via a network; and selection circuits for conducting at least one of: switching from said first video data to said second video data; switching from said first audio data to said second audio data, and switching from said first subpicture data to said second subpicture data; wherein data which is newly switched by said selection circuits and data which is not switched by said selection circuits are synchronously superimposed and outputted.