Patent ID: 7893996

Claim:
A video switcher which transmits a video signal and a synchronization signal corresponding to the video signal to a video display unit, the transmitted video signal and synchronization signal are supplied from one video input unit selected from a plurality of video input units by a switching operation, the video switcher comprising: a video signal switching device which switches a video signal to be transmitted to the video display unit from the first video signal supplied from a first video input unit before a completion of the switching operation to a second video signal supplied from a second video input unit after the completion of the switching operation; a synchronization signal switching device which switches the synchronization signal to be transmitted to the video display unit from a first synchronization signal supplied from the first video input unit to a second synchronization signal supplied from the second video input unit, and a storage unit for storing a constant time period between a stop of transmission of the first synchronization signal to the video display unit and a start of transmission of the second synchronization signal to the video display unit, wherein the synchronization signal switching device starts to transmit the second synchronization signal to the video display unit after a lapse of the constant time period from the stop of transmission of the first synchronization signal, and the video signal switching device stops to transmit the first video signal before the stop of transmission of the first synchronization signal and starts to transmit the second video signal after the start of transmission of the second synchronization signal.