| 摘要 |
PROBLEM TO BE SOLVED: To let a user know whether an operation key is effective or ineffective and to improve usability by displaying the state that the operation that the user instructs with the operation key is limited by header information stored in a memory in such a case. SOLUTION: Header information, video information, and audio information transmitted from a drive part 33 are inputted to an AV decoder 34 and video and audio data are decoded and outputted; and limitation information included in the header information is analyzed by a CPU 35 and stored in the memory of a decoder 34. When key input information by user's key input is received through a user interface 38, the CPU 35 reads the limitation information out of the memory and compares it with bit position data of operation limitation information corresponding to the key input information. When the operation corresponding to the key is possible, a specific operation process is performed, but when not, specific figure information is mixed with video by an on-screen display generation part and the operation process is not performed. |
