Editing Interlaced video (section)

==Deinterlacing==
{{main|Deinterlacing}}
{{Unreferenced section|date=May 2023}}
ALiS plasma panels and the old CRTs can display interlaced video directly, but modern computer video displays and TV sets are mostly based on LCD technology, which mostly use progressive scanning.

Displaying interlaced video on a progressive scan display requires a process called [[deinterlacing]]. This is can be an imperfect technique, especially if the frame rate isn't doubled in the deinterlaced output. Providing the best picture quality for interlaced video signals without doubling the frame rate requires expensive and complex devices and algorithms, and can cause various artifacts. For television displays, deinterlacing systems are integrated into progressive scan TV sets that accept interlaced signal, such as broadcast SDTV signal.

Most modern computer monitors do not support interlaced video, besides some [[IBM 8514|legacy medium-resolution modes]] (and possibly 1080i as an adjunct to 1080p), and support for standard-definition video (480/576i or 240/288p) is particularly rare given its much lower line-scanning frequency vs typical "VGA"-or-higher analog computer video modes. Playing back interlaced video from a DVD, digital file or analog capture card on a computer display instead requires some form of [[deinterlacing]] in the player software and/or graphics hardware, which often uses very simple methods to deinterlace. This means that interlaced video often has visible artifacts on computer systems. Computer systems may be used to edit interlaced video, but the disparity between computer video display systems and interlaced television signal formats means that the video content being edited cannot be viewed properly without separate video display hardware.

Current manufacture TV sets employ a system of intelligently extrapolating the extra information that would be present in a progressive signal entirely from an interlaced original. In theory: this should simply be a problem of applying the appropriate algorithms to the interlaced signal, as all information should be present in that signal. In practice, results are currently variable, and depend on the quality of the input signal and amount of processing power applied to the conversion.  The biggest impediment, at present, is artifacts in the lower quality interlaced signals (generally broadcast video), as these are not consistent from field to field.  On the other hand, high bit rate interlaced signals such as from HD camcorders operating in their highest bit rate mode work well.

Deinterlacing algorithms temporarily store a few frames of interlaced images and then extrapolate extra frame data to make a smooth flicker-free image. This frame storage and processing results in a slight [[display lag]] that is visible in business showrooms with a large number of different models on display. Unlike the old unprocessed NTSC signal, the screens do not all follow motion in perfect synchrony. Some models appear to update slightly faster or slower than others. Similarly, the audio can have an echo effect due to different processing delays.