Mobile telephone device

A mobile telephone device provided with a video display mode displaying a video based on video data, and a telephone mode, comprising:

• a display screen;
• a speaker;
• a memory for storing first display setting information and first sound setting information in the video display mode and second display setting information and second sound setting information in the telephone mode, wherein the second display setting information is configured to be set by a user input to provide a luminance that is greater than zero;
• and
• a processor configured to control the display screen and the speaker based on the first display setting information and the first sound setting information during the video display mode, and configured to control the display screen and the speaker based on the second display setting information and the second sound setting information during the telephone mode,
• wherein the second display setting information comprises information for lowering a screen luminance of the display screen with passage of a first time period such that the image in the telephone mode continues to be displayed on the display screen with reduced luminance, and the first display setting information comprises information for not lowering the screen luminance of the display screen with passage of the first time period when the video in the video display mode is displayed on the display screen.