Data transmission system, and its transmission side apparatus and reception side apparatus

A transmission side apparatus for use in a data transmission system, selectively transmitting information data in addition to video stream data between apparatuses which employ an SDI (serial digital interface) system or an HD (high definition)-SDI system to transmit the video stream data via a transmission path, comprising:

• a data insertion unit to insert selectively the information data into a video storage area to store video stream' data in a frame structure of the SDI system or HD-SDI system therein to generate SDI data;
• and
• a transmission unit to transmit the SDI data to the transmission path,
• wherein the data insertion unit generates identification information indicating whether the data to be transmitted is the video stream data or the information data other than the video data and, when storing the data to be transmitted in the video storage area, stores the identification information in an auxiliary data area prepared independently from the video storage area,
• wherein the data transmission system comprises the transmission side apparatus and a reception side apparatus provided with a reception unit to receive the SDI data transmitted via the transmission path and with a data extraction unit to extract data to be transmitted from the video storage area of the SDI data and to determine whether the data to be transmitted is the video stream data or the information data to selectively switch and output it,
• wherein the data extraction unit determines a type of the data to be transmitted from the identification information in the auxiliary data area when extracting the data to be transmitted from the video storage area of the auxiliary data area.