Video data transmission and reception method using high-speed interface, and apparatus therefor

A source device transmitting video data based on a high definition multimedia interface (HDMI), the source device comprising:

• the HDMI;
• and
• a processor,
• wherein the processor is configured to control the HDMI to:
• receive, from a sink device, capability information indicating whether the sink device supports image processing based on a predefined reference display model (RDM);
• perform image processing on a plurality of video data using the predefined RDM stored in the source device, based on the capability information and in absence of receiving display information from the sink device;
• transmit, to the sink device:
• (i) the plurality of video data processed based on the predefined RDM, and
• (ii) image processing information including at least one of RDM mean brightness, RDM luminance, RDM color, or RDM type, representing a result of the image processing based on the predefined RDM,
• wherein the image processing based on the predefined RDM comprises performing tone mapping on the plurality of video data based on a luminance characteristic value of one video data selected from among the plurality of video data having different HDR luminance ranges, wherein the one video data is video data having a smallest value of the HDR luminance range among the plurality of video data.