A communication device configured to transmit or receive, respectively, encoded data that is obtained through scalable coding to or from, respectively, at least one other communication device, decode the received encoded data, and reproduce and output the data, the communication device comprising: a notification unit configured to notify the at least one other communication device from which data being reproduced and output is transmitted, of reproduction quality information representing quality of the data being reproduced and output; characterized by an encoding setting control unit configured to control a setting for encoding the encoded data to be transmitted to the at least one other communication device from which reproduction quality information is notified, based on the reproduction quality information that is notified from the at least one other communication device, wherein the reproduction quality information contains items of a communication device being a transmission source, a display type, a resolution, and a frame rate, wherein, the encoding setting control unit is configured to, in a case where the at least one other communication device includes a plurality of other communication devices and the encoded data that is common among the plurality of other communication devices is transmitted to the plurality of other communication devices, and if highest quality among qualities represented by a plurality of sets of reproduction quality information that are notified from the plurality of other communication devices is lower than quality of the common encoded data that is transmitted to the plurality of other communication devices, change the setting for encoding the common encoded data to be transmitted to the plurality of other communication devices such that quality exceeding the highest quality is not contained, wherein the communication device is configured to transmit or receive, respectively, the encoded data via a relay server. a notification unit configured to notify the at least one other communication device from which data being reproduced and output is transmitted, of reproduction quality information representing quality of the data being reproduced and output; characterized by an encoding setting control unit configured to control a setting for encoding the encoded data to be transmitted to the at least one other communication device from which reproduction quality information is notified, based on the reproduction quality information that is notified from the at least one other communication device, wherein the reproduction quality information contains items of a communication device being a transmission source, a display type, a resolution, and a frame rate, wherein, the encoding setting control unit is configured to, in a case where the at least one other communication device includes a plurality of other communication devices and the encoded data that is common among the plurality of other communication devices is transmitted to the plurality of other communication devices, and if highest quality among qualities represented by a plurality of sets of reproduction quality information that are notified from the plurality of other communication devices is lower than quality of the common encoded data that is transmitted to the plurality of other communication devices, change the setting for encoding the common encoded data to be transmitted to the plurality of other communication devices such that quality exceeding the highest quality is not contained, wherein the communication device is configured to transmit or receive, respectively, the encoded data via a relay server.