A multiple ROI setting method and apparatus in scalable video coding and an ROI reconstructing method and apparatus are provided. A transmitter transmits a preamble or a pilot to a receiver. The second dichroic mirror is configured to reflect the first and the second light beams transmitted from the first dichroic mirror and to transmit the third light beam. When a phase shift mask is manufactured from the blank, the substrate is less prone to overetching, providing good controllability and in-plane uniformity of the phase shift in patterned areas.