Network data distribution system

A data distribution server used in a network data distribution system for distributing encoded data from a server side to clients via a network, the server comprising:

• packet data forming means for dividing data requested from a client into packets, and forming packet data by adding a time index relating to a process used for processing each divided packet to the packet;
• and
• sending means for sending the packet data to the client which requested the data, and for selecting the packet data to be next transmitted based on delay time information communicated by the client, the information relating to transmission or a decoding process with respect to the packet data;
• and sending the selected packet data.

A client apparatus used in a network data distribution system for distributing encoded data from a server side to clients via a network, the apparatus comprising:

• request means for requesting desired data from the server;
• receiving means for receiving the packet data sent from the server;
• transmission delay calculating means for calculating an amount of transmission delay based on a time index included in the packet data received by the receiving means, the time index relating to a process used for processing the packet data;
• process delay calculating means for calculating an amount of process delay relating to decoding of the received packet data, based on the time index included in the packet data received by the receiving means;
• and
• delay information communicating means for communicating delay time information based on the calculated amount of transmission or process delay to the server.

A client-side control method used in a network data distribution system for distributing encoded data from a server side to clients via a network, the method comprising the steps of:

• requesting desired data from the server;
• receiving the packet data sent from the server;
• calculating an amount of transmission delay based on a time index included in the received packet data, the time index relating to a process used for processing the packet data;
• calculating an amount of process delay relating to decoding of the received packet data, based on the time index included in the received packet data;
• and
• communicating delay time information based on the calculated amount of transmission or process delay to the server.