Patent ID: 7907594

Claim:
A method for marking a keyframe of a media stream in a communication system, comprising: performing, by each entry media switch of one or more entry media switches, the following: facilitating communication of a plurality of packets in a plurality of media streams from a plurality of endpoints, each endpoint configured to support communication of packets, each packet having an endpoint sequence number assigned by the endpoint; selecting an endpoint of the plurality of endpoints as an active speaker of a conference session, an active media stream of the active speaker to be sent to the other endpoints; receiving the active media stream from the selected endpoint, the active media stream comprising a keyframe operable to be decoded independently of any other frame, the keyframe indicating a switch to the active speaker; assigning, by the each entry media switch, an upstream sequence number to each packet of the active media stream such that each packet has an upstream sequence number and an endpoint sequence number, the upstream sequence number used to establish the order of the packets; and notifying a downstream media switch of the keyframe by marking the keyframe with a keyframe indicator and sending the active media stream to the downstream media switch in an output media stream to allow the down stream media switch configured to receive a combined stream comprising the one or more output media streams and the one or more keyframe indicators of the one or more output media streams, the down stream media switch configured to apply a reordering scheme to establish the order of the packets of the combined stream in accordance with the one or more keyframe indicators by calculating a corrected downstream sequence number from a difference between an upstream sequence number and a correction factor, the correction factor determined from a function of an upstream sequence number of a switching packet of the media stream of the active speaker, a downstream sequence number of the switching packet, and a header extension sequence number of the switching packet.