Synchronization Method for Stereoscopic 3D Video Broadcasting through Heterogeneous Network

This paper proposes a method to provide the frame synchronization for the high quality 3D broadcasting service in a mobile broadcasting system. In this method, left and right video frames are delivered through a heterogeneous network which consists of a mobile network and a broadcasting network, to overcome the limited bandwidth of the broadcasting network. Then it is more difficult to synchronize the left and right video frames coming through different types of networks. In the beginning, the proposed method uses only the offset from the initial timestamp of RTP (Real Time Protocol) to determine the order of frames and to find the pair of a left and a right frame that must be played at the same time. However, the method using the initial timestamp only may not resolve the PCR (Program Reference Clock) discontinuity problem of the broadcasting system. Thus the proposed method is enhanced to periodically send RTCP (Real Time Control Protocol) which includes current timestamps of a pair of frames on mobile and broadcasting networks. Additionally, a new signaling method is introduced for a mobile device to request a 3D service and to get the initial RTP timestamp.