Method for data distribution

Abstract

Stream data is transmitted from a distribution server to a client without any loss of data. The capacity of a reception buffer to be prepared at the client can be made small and the network bandwidth necessary for data redistribution can be narrowed. A relay server interposed between the distribution server and client buffers stream data in an auxiliary storage device. When the relay server or client detects a loss of stream data, a redistribution request is transmitted to the distribution server or another relay server at the preceding stage.

1 - 10 . (canceled) 
     
     
         11 . A relay server for relaying data transmitted between a distribution server and a client apparatus via a network comprising:
 a storage device that stores stream data transmitted from the distribution server to the client apparatus;   a distribution request processing module that receives a distribution request sent from the client apparatus to obtain the stream data from the distribution server, the distribution request including information of requesting the quality of the stream data to be distributed from the distribution server;   a quality request module that reads the requested quality of the stream data out of the distribution request, reads the stream data requested by the distribution request from the storage device, thins the stream data according to the requested quality to send the thinned stream data to the client apparatus;   a redistribution processing module that receives a redistribution request from the client apparatus of which includes time information indicating time to send the stream data to the client apparatus;   a transmission processing module that reads the stream data out of the storage device when time comes to time included in the data stream and distributes the stream data to the client apparatus; and   a quality request processing module that receives a quality change request sent from the client terminal and changes a thinning rate of the stream data according to the quality request.   
     
     
         12 . The relay server according to  claim 11 , wherein said quality request processing module changes a frame rate according to said quality request. 
     
     
         13 . The relay server according to  claim 11 , wherein said quality request processing module changes a frame rate of the stream data according to said quality request. 
     
     
         14 . The relay server according to  claim 11 , wherein said quality request processing module changes to increase the thinning rate of the stream data according to said quality request for lowering the quality when the network is in an overload state. 
     
     
         15 . The relay server according to  claim 11 , wherein the relay server stores IP addresses of its own server to data to be relayed;
 if the relay server detects a loss of data stored in the second information storage device, it reads out an IP address of the distribution server or another relay server placed at a preceding stage stored in the data and transmits a redistribution request of data to another relay server at a preceding stage.   
     
     
         16 . A data transmission method between a distribution server and a client apparatus via a network comprising:
 storing stream data transmitted from the distribution server to the client apparatus;   receiving a distribution request sent from the client apparatus to obtain the stream data from the distribution server, the distribution request including information of requesting the quality of the stream data to be distributed from the distribution server;   reading the requested quality of the stream data out of the distribution request, reading the stream data requested by the distribution request from the storage device and thinning the stream data according to the requested quality to send the thinned stream data to the client apparatus;   receiving a redistribution request from the client apparatus of which includes time information indicating time to send the stream data to the client apparatus;   reading the stream data out of the storage device when time comes to time included in the data stream and distributing the stream data to the client apparatus; and   receiving a quality change request sent from the client terminal and changing a thinning rate of the stream data according to the quality request.   
     
     
         17 . The data transmission method according to  claim 16 , wherein said changing the thinning rate comprises changing a frame rate according to said quality request. 
     
     
         18 . The data transmission method according to  claim 16 , wherein said changing the thinning rate comprises changing a frame rate of the stream data according to said quality request. 
     
     
         19 . The data transmission method according to  claim 16 , wherein said changing the thinning rate comprises changing to increase the thinning rate of the stream data according to said quality request for lowering the quality when the network is in an overload state. 
     
     
         20 . The data transmission method according to  claim 16 , wherein the relay server stores IP addresses of its own server to data to be relayed;
 if the relay server detects a loss of data stored in the second information storage device, it reads out an IP address of the distribution server or another relay server placed at a preceding stage stored in the data and transmits a redistribution request of data to another relay server at a preceding stage.