Patent ID: 7508760

Claim:
A distribution server comprising: an image data generating unit that generates a first image data fragment and a second image data fragment, which is a next fragment of said first image data fragment; a communication unit that transmits and receives data to and from a terminal through a communication path; and a bit rate switching control unit that controls said image data generating unit to change an image bit rate, wherein said image data generating unit inserts monitoring trigger information, which indicates a transmission start time of said second image data fragment, into said first image data fragment and inserts data size information, which indicates a data size of said second image data fragment, into said second image data fragment, for executing a receiving bit rate calculation in a receiving side by dividing said data size of said second image data fragment by an interval of time between the start time calculated based on said transmission start time and the end time detected based on said data size of said second image data fragment, and wherein when said communication unit receives an image bit rate switching request command from said terminal which is generated based on said receiving bit rate calculation, said bit rate switching control unit controls said image data generating unit to change an image bit rate.