Patent ID: 8488066

Claim:
A system for changing digital channel, the system comprising: an auxiliary channel generating unit, configured to generate one or more auxiliary channels carrying cached video data that is identical to video data carried by a target channel, and to simultaneously send the video data of the target channel and the cached video data of the one or more auxiliary channels to a client device, wherein the target channel and the auxiliary channel are both multicast channels addressed to a multicast group of client devices and not to individual client devices; the client device, configured to receive the video data carried by the target channel and the cached video data carried from the one or more auxiliary channels at the same time when the client device changes to the target channel; and a video data receiving controller, configured to detect the video data received by the client device from the target channel or from the one or more auxiliary channels, and to send a message of terminating receiving the video data from one of the target channel or the one or more auxiliary channels to the client device upon either detecting that a first video data package received over the target channel concatenates in sequence with a last video data package received over the one or more auxiliary channels or detecting that an I-frame is received over the target channel or the one or more auxiliary channels.