Patent ID: 8704863

Claim:
A method performed on a client device for transitioning between a circuit switched audio call established over a first network and an Internet Protocol (IP) video call over a second network, the client device including a camera to capture video for the video call, the method comprising: receiving input from a user of the client device to transition from the established circuit switched audio call to an IP video call, wherein the established circuit switched audio call has a plurality of participants including the user of the client device and a set of one or more remote participants at a set of one or more other client devices; causing an IP video call invitation message to be transmitted to the set of other client devices of the remote participants; receiving an IP video call accept message from the set of other client devices of the set of remote participants; transmitting video captured by the camera of the client device to the set of other client devices of the set of remote participants; and responsive to receiving at least a video frame from each of the set of other client devices of the set of remote participants, transitioning from the circuit switched audio call on the first network to the IP video call on the second network while maintaining the audio of the circuit switched audio call open for participant communication until the IP video call is established, wherein the maintaining audio of the circuit switched audio call includes transmitting live audio data to each of the set of other client devices of the set of remote participants over the circuit switched audio call until completing the transitioning to the IP video call.