An encoder (100) includes circuitry and memory coupled to the circuitry. In operation, the circuitry determines whether or not a current video to be processed is a progressive video (S201). When it is determined that the current video is a progressive video (Yes in S201), the encoder (100) encodes, into a bitstream, one syntax element indicating a chroma location type which is information indicating locations of chroma samples relative to luma samples for a frame included in the current video (S202). When it is determined that the current video is not a progressive video (No in S201), the encoder (100) encodes two syntax elements into the bitstream, each of which indicates the chroma location type for a different one of fields of two types included in the current video (S203).