Originally Posted by kolak
For that you just encode with interlace flagging. There is no need to make content really interlaced.
Sure. I just remember cases from the early days of DVD where "pseudo-interlaced" was created by phase shifting fields, means taking the top field from the current frame and the bottom field from the next frame of a progressive source. It didn't look nice when throwing a deinterlacer at such footage instead of matching the fields to restore the original progressive frames. Interestingly, such material was even proposed for testing deinterlacers.