SeparateFields (clip)

NTSC and PAL video signals are sequences of fields, but all capture cards that I'm aware of capture two fields at a time and interlace (or "weave") them into frames. So frame 0 in the capture file contains fields 0 and 1; frame 1 contains fields 2 and 3; and so on. SeparateFields takes a frame-based clip and splits each frame into its component fields, producing a new clip with twice the frame rate and twice the frame count. This is useful if you would like to use Trim and similar filters with single-field accuracy.

SeparateFields uses the field-dominance information in the source clip to decide which of each pair of fields to place first in the output. If it gets it wrong, use ComplementParity, AssumeTFF or AssumeBFF before SeparateFields.

From version 2.5.6 this filter raises an exception if the clip is already field-based. You may want to use AssumeFrameBased to force separate a second time. Prior versions did a no-op for materials that was already field-based.

$Date: 2006/12/14 22:55:04 $