Interlacing vs progressive
Also known as: interlaced video, progressive scan, 1080i vs 1080p, deinterlacing
Interlaced video draws each frame as two alternating fields of odd and even lines, while progressive video draws every line in order as a full frame. The "i" and "p" in formats like 1080i and 1080p mark the difference — modern screens and files are almost all progressive.
- Interlaced = alternating odd/even line fields
- Progressive = full frame drawn in one pass
- Modern video is almost all progressive (p)
Two ways to draw a frame
Interlacing is a legacy broadcast technique: each frame is split into two fields, one holding the odd horizontal lines and one the even, displayed in quick succession. It saved bandwidth on old TV systems by sending half the lines at a time.
Progressive scanning draws all lines of each frame top to bottom in a single pass, the way phones, computers, and modern displays work. It produces a cleaner image with no combing artifacts on motion.
Why progressive won and deinterlacing
On fast motion, interlaced footage can show comb-like lines where the two fields no longer align, so playing it on a progressive screen often needs deinterlacing to reconstruct full frames. That conversion can soften the image or introduce artifacts.
Today nearly all capture, editing, and delivery is progressive (the "p" formats). You mainly meet interlacing when working with old TV recordings, DVD content, or some camcorder footage.