A display signal processing system according to the embodiment includes: a processing device configured to generate transmission data; an interface unit configured to transmit the transmission data; and a display unit configured to generate a display signal based on the transmission data. The processing device includes a SDR conversion unit configured to generate low-bit video data by decimating gradations of the video signal; an additional data calculation unit configured to generate additional data on the basis of information of the decimated gradations; and a mapping unit configured to generate the transmission signal including the low-bit video data and the additional data. The display unit includes a processor configured to restore at least a part of the decimated gradations in the low-bit video data on the basis of the transmission signal to thereby generate a display signal.