# SeparateFields / SeparateColumns / SeparateRows

`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 half height 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.

See also: Weave.

`SeparateColumns` (clip, “interval”)
`SeparateRows` (clip, “interval”)

`SeparateColumns` separates the columns of each frame into interval frames. The number of frames of the new clip is interval times the number of frames of the old clip. The width of the frame must be a multiple of interval, otherwise an error is thrown. SeparateColumns is a relatively slow filter due to the sparse pixel picking required by the algorithm. In some applications it may be faster to use TurnLeft/Right with SeparateRows.

`SeparateRows` separates the rows of each frame into interval frames. The number of frames of the new clip is interval times the number of frames of the old clip. The height of the frame must be a multiple of interval, otherwise an error is thrown. SeparateRows like SeparateFields is very fast as it uses zero cost subframing to perform it’s magic.

`SeparateRows(2)` is the same as `SeparateFields()` except the output is frame-based instead of field-based.

Examples:

    # returns the original clip:
    AviSource("c:\file.avi")
    SeparateColumns(1)

    # returns a clip where the columns are separated:
    # frame 0 consists of the columns 0,3,6,... of the original frame 0
    # frame 1 consists of the columns 1,4,7,... of the original frame 0
    # frame 2 consists of the columns 2,5,8,... of the original frame 0
    # frame 3 consists of the columns 0,3,6,... of the original frame 1
    # etc ...
    AviSource("c:\file.avi")
    SeparateColumns(3)

    # returns a clip where the rows are separated:
    # frame 0 consists of the rows 0,2,4,... of the original frame 0
    # frame 1 consists of the rows 1,3,5,... of the original frame 0
    # frame 2 consists of the rows 0,2,4,... of the original frame 1
    # frame 3 consists of the rows 1,3,5,... of the original frame 1
    # etc ...
    AviSource("c:\file.avi")
    SeparateRows(2)

Changes |
--- | ---
v2.60 | Added SeparateColumns and SeparateRows.

$Date: 2012/04/15 14:59:41 $