Editing NTSC (section)

=== Field order ===
An NTSC ''frame'' consists of two ''fields,'' F1 (field one) and F2 (field two). The [[field dominance]] depends on a combination of factors, including decisions by various equipment manufacturers as well as historical conventions. As a result, most professional equipment has the option to switch between a dominant upper or dominant lower field. It is not advisable to use the terms ''even'' or ''odd'' when speaking of fields, due to substantial ambiguity. For instance if the line numbering for a particular system starts at zero, while another system starts its line numbering at one. As such the same field could be even or odd.<ref name=":0" /><ref>{{cite web |title=Programmer's Guide to Video Systems - Lurker's Guide - lurkertech.com |url=https://lurkertech.com/lg/video-systems/#f1f2 |access-date=January 25, 2023 |website=lurkertech.com}}</ref>

While an analog television set does not care about field dominance per se, field dominance is important when editing NTSC video. Incorrect interpretation of field order can cause a shuddering effect as moving objects jump forward and behind on each successive field.

This is of particular importance when interlaced NTSC is transcoded to a format with a different field dominance and vice versa. Field order is also important when transcoding progressive video to interlaced NTSC, as any place there is a cut between two scenes in the progressive video, there could be a flash field in the interlaced video if the field dominance is incorrect. The film telecine process where a [[three-two pull down]] is utilized to convert 24 frames to 30, will also provide unacceptable results if the field order is incorrect.

Because each field is temporally unique for material captured with an interlaced camera, converting interlaced to a digital progressive-frame medium is difficult, as each progressive frame will have artifacts of motion on every alternating line. This can be observed in PC-based video-playing utilities and is frequently solved simply by transcoding the video at half resolution and only using one of the two available fields.