In video engineering, field dominance refers to the choice of which field

Field (video)

In video, a field is one of the many still images which are displayed sequentially to create the impression of motion on the screen. Two fields comprise one video frame...

 of an interlaced video signal

Composite video

Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level 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

480i

480i is the shorthand name for a video mode, namely the US NTSC television system or digital television systems with the same characteristics. The i, which is sometimes uppercase, stands for interlaced, the 480 for a vertical frame resolution of 480 lines containing picture information; while NTSC...

 – often referred to as NTSC

NTSC

NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...

) or 1/50 of a second under the 625-line system (or 576i

576i

576i is a standard-definition video mode used in PAL and SECAM countries. In digital applications it is usually referred to as "576i", in analogue contexts it is often quoted as "625 lines"...

 – often incorrectly referred to as the PAL

PAL

PAL, short for Phase Alternating Line, is an analogue television colour encoding system used in broadcast television systems in many countries. Other common analogue television systems are NTSC and SECAM. This page primarily discusses the PAL colour encoding system...

 system) . Proper field dominance selection in linear editing systems will maintain color framing

Color framing

In video engineering, color framing refers to the color frame sequence of fields in a composite video signal through which the video frame timing and chrominance subcarrier signal timing—in particular, that of the color burst -- cycle through all possible phase relationships.The exact nature of the...

 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

DVD

A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

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.

External links

• http://www.lurkertech.com/lg/dominance.html
• http://lurkertech.com/lg/dominanceorigin.html
• http://www.mir.com/DMG/interl.html