Embodiments of the present invention provide a method of identifying inconsistent field order flags for a sequence of video frames comprising: for each frame in the sequence of video frames analyzing the frame to make an initial determination of the field order for that frame; averaging the initial determination of the field order over a predefined number of most recently analyzed frames; and determining those frames for which the averaged field order does not match the field order identified by a respective field order metadata item associated with each frame by comparing the averaged field order for each frame to the respective field order metadata item.