A handheld communication device is used to capture video streams and generate a multiplexed video stream. The handheld communication device has at least two cameras facing in two opposite directions. The handheld communication device receives a first video stream and a second video stream simultaneously from the two cameras. The handheld communication device detects a speech activity of a person captured in the video streams. The speech activity may be detected from direction of sound or lip movement of the person. Based on the detection, the handheld communication device automatically switches between the first video stream and the second video stream to generate a multiplexed video stream. The multiplexed video stream interleaves segments of the first video stream and segments of the second video stream. Other embodiments are also described and claimed.