Editing Video > Editing clips > Processing interlaced video fields
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Processing interlaced video fields


In some video sources, such as NTSC, PAL, or SECAM, each video frame consists of two interlaced fields, each one representing a particular point in time. One field contains the odd-numbered lines in the frame, and the other contains the even-numbered lines. The two fields display in sequence to create a frame, but the field dominance, or the field displayed first, can vary depending on the video format and the equipment used to capture and play it. If the field dominance is reversed, motion may flicker or appear jerky because the fields no longer display chronologically. Fields can become reversed in the following situations:
  • The field dominance of the original videotape was the opposite of the field dominance of the video-capture card used to capture the clip.
  • The field dominance of the original videotape was the opposite of the field dominance of the video-editing or animation software that last rendered the clip.
  • You have set an interlaced clip to play backward in Premiere.

    • Premiere can process fields for an interlaced clip in the Timeline so that the clip's picture and motion quality are preserved in situations such as changing the clip speed, exporting a filmstrip, playing a clip backwards, or freezing a video frame. The following settings operate on individual clips; final results are affected by the project settings in the Keyframe and Rendering Options (see the description of the Field Settings option in Keyframe and rendering options and Exporting a video).

    To specify field processing options for a clip:

    1 Select a clip in the Timeline.

    2 Choose Clip > Video Options > Field Options.

    3 Select Reverse Field Dominance if the field dominance of the selected clip is the opposite of the field dominance used by your video-capture card. This option is also useful when your project contains clips captured using different video-capture cards or when you play a clip backward.

    4 Click one of the following Processing Options:
  • Select None if you don't want to process source clip fields.
  • Select Interlace Consecutive Frames to convert pairs of progressive-scan (noninterlaced) frames into interlaced fields. This option is useful for converting 60-fps progressive-scan animations into 30-fps interlaced video, because many animation applications don't create interlaced frames.
  • Select Always Deinterlace if you want to convert interlaced fields into whole progressive-scan frames. Premiere deinterlaces by discarding one field and interpolating a new field based on the lines of the remaining field. It keeps the field specified in the Field Settings option (see Keyframe and rendering options and Exporting a video). If you specified No Fields, Premiere keeps the Upper Field unless you selected Reverse Field Dominance, in which case it keeps the lower field. This option is useful when freezing a frame in the clip.
  • Select Flicker Removal to stop a small object in a picture from flickering, such as a one-pixel horizontal line. This option is sometimes known as vertical convolution, and can be useful with still images. If an object is as thin as a single scan line, it may appear only in one of the two video fields. This causes flicker because the object is drawn only as every other field appears. When you select Flicker Removal, Premiere blurs the two fields together slightly so that thin objects appear at least partially in both fields. The full resolution of the frame is preserved.

    • 5 Select Deinterlace When Speed is Below 100% to automatically identify and retain fields that would best provide smooth-looking slow motion. Whether or not the upper or lower field in the successive frames is kept will depend on when that frame occurs. When you're done, click OK.

    Editing Video > Editing clips > Processing interlaced video fields