Patent ID: 7814515

Claim:
A transmission server for digitally delivering a data packet to a receiver through a transmission channel, comprising: a generating section that generates (1) a video data packet including digital data of video information of a content and digital data of video reproduction timing information on a timing at which the digital data of video information is reproduced, (2) a video synchronization signal packet including a video synchronization signal which includes a video data reproducing base time value that correlates the video reproduction timing information with a first time on a predetermined reference time axis, (3) an audio data packet including digital data of audio information of the same content and digital data of audio reproduction timing information on a timing at which the digital data of audio information is reproduced, and (4) an audio synchronization signal packet including an audio synchronization signal which includes an audio data reproducing base time value that correlates the audio reproduction timing information with a second time on the predetermined reference time axis; and a delivering section that delivers the video data packet and the video synchronization signal packet to a first receiver and delivers the audio data packet and the audio synchronization signal packet to a second receiver without synchronizing a timing of delivering the video data packet and a timing of delivering the audio data packet with each other.