Field dominance

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In video engineering, field dominance refers to the choice of which field of an interlaced video signal is chosen as the point at which video edits occur. There are only two choices for field dominance in normal interlaced video: odd or even. Interlacing divides the frame into two fields, scanning alternately the odd-numbered lines and even-numbered lines. Each field is scanned in 1/60 second under the 525-line NTSC system (or 480i – often referred to as NTSC) or 1/50 of a second under the 625-line system (or 576i – often incorrectly referred to as the PAL system) . Proper field dominance selection in linear editing systems will maintain color framing synchronization.

A complete video frame in the 525-line system consists of an even-line field followed by an odd-line field. In the 625-line system, a complete video frame consists of an odd line field followed by an even line field. Most digital video formats (including the DVD format) store the even field of the complete frame first regardless of the field order of the actual material.

Re-editing old video material already edited with a different field dominance convention can be problematic, as it can lead to "flash fields" when old and new edits are made too close together.

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