A videoconference system is provided. The videoconference system includes a plurality of clients. A server component configured to distribute media to the plurality of clients is included. The server component includes a media mixer enabling distribution of a composite audio/video data stream to the client component and a videoconference choreographer configured to assist the media mixer in mixing input streams to the server component based upon event data. A conference channel communication connection over which video and audio data streams are carried between the plurality of clients and the server component is provided. A back-channel communication connection over which the event data is communicated between the plurality of clients and the server component is also included. A method for controlling mixing of data streams for a videoconference session is also provided. A scheme for converting documents to be shared during a videoconference session to a common format is also provided.