| 摘要 |
<p>Transitioning between an audio only circuit switched call and a video call. A client device, which is currently connected to one or more other client devices through an established audio only circuit switched call, receives input from a user to transition from the audio only circuit switched call to the video call. A video call invitation message is transmitted to the other client devices. The client device receives a video call accept message from the other client devices and begins transmitting video captured by its front facing camera to the other client devices. Responsive to receiving at least a video frame from each of the one or more other client devices, the client device transitions from the audio only circuit switched call to the video call. After transitioning to the video call, the circuit switched call is dropped.</p> |
