A method for encoding a video signal with both interlaced and progressive content using lookahead is disclosed. The method may include steps (A) to (C). Step (A) may calculate a cost of being interlaced within each of a plurality of windows in the video signal. The video signal generally has a plurality of interlaced fields and a plurality of progressive frames. Step (B) may determine a plurality of points in the video signal. Step (C) may encode the video signal with switching between a field mode and a frame mode at one or more of the points based on the costs. The encoding may be a high efficiency video coding.