Video interface conversion device and method

The present disclosure discloses a video interface conversion device that includes a first and a second interface transmission circuit, a color conversion circuit and an image compression circuit. The first and the second interface transmission circuit are respectively electrically coupled to an image source and a display terminal. The second interface transmission circuit negotiates a maximum output bandwidth with the display terminal such that the first interface transmission circuit compares an input data bandwidth of a data signal received from the image source and the maximum output bandwidth. When the maximum output bandwidth is smaller than the input data bandwidth, an image compression and/or a color coding conversion is performed on the data signal, and the data signal having the processed input data bandwidth being smaller than or equal to the maximum output bandwidth is further transmitted by the second interface transmission circuit to the display terminal.