1 ) Conference system of the type that comprises a bridge ( 10 ) to which a plurality of terminals ( 1 to 4 ) can be connected to participate in a conference, said bridge ( 10 ) being equipped to receive audio and/or video and/or data flows from each terminal ( 1 to 4 ) and retransmit them to the other terminals, wherein the flows transmitted by said terminals ( 1 to 4 ) are coded by means of hierarchical coders and wherein said bridge ( 10 ) is equipped with means ( 21 to 24 , 210 to 243 ) for processing the audio/video/data flows coming from the terminals (j) so that they have a hierarchical level (q) in the flow intended for the terminal (i) and means ( 20 ) for determining said hierarchical level (q) based on decision-making criteria related to the status of said conference system.