Patent ID: 8451375
Filing Date: 2013-05-28
Classification: H04N

Abstract:
1. An extra delay time calculating method for calculating an extra delay time for which an audio signal is additionally delayed when a sink device reproduces the audio signal in a Lip-sync correction system that transmits a video signal from a source device to the sink device through a first transmission path, transmits the audio signal from the source device to the sink device through a second transmission path different from the first transmission path, and reproduces the video signal and the audio signal in synchronous with each other on the sink device, wherein a communication from the source device to the sink device is defined as a downstream communication, and a communication from the source device to the sink device is defined as a upstream communication, at least one device is connected on the first transmission path, and at least one device is connected on the second transmission path, the extra delay time calculating method comprises: transmitting sequentially an inquiry command from the source device to the sink device in an order of the connection of the at least one device through the downstream communication on the first transmission path; receiving a first total delay time as a signal in response to the inquiry command by the source device, the first total delay time being a total delay time of the video signal resulting from the transmission of the video signal from the source device to the sink device through the downstream communication on the first transmission path; outputting the first total delay time through the downstream communication on the second transmission path by the source device; obtaining the first total delay time output from the source device and a second total delay time by a controller in a reproducing system, the second total delay time being a total delay time of the audio signal resulting from the transmission of the audio signal from the source device to the sink device through the downstream communication on the second transmission path; and calculating a difference value between the obtained first total delay time and second total delay time as the extra delay time, by the controller.