VapourSynth R54 documentation

# SelectEvery

std.SelectEvery(clip clip, int cycle, int[] offsets[, bint modify_duration=True])

  Returns a clip with only some of the frames in every cycle selected. The offsets given must be between 0 and cycle - 1.

  Below are some examples of useful operations.

  Return even numbered frames, starting with 0:

      SelectEvery(clip=clip, cycle=2, offsets=0)

  Return odd numbered frames, starting with 1:

      SelectEvery(clip=clip, cycle=2, offsets=1)

  Fixed pattern 1 in 5 decimation, first frame in every cycle removed:

      SelectEvery(clip=clip, cycle=5, offsets=[1, 2, 3, 4])

  Duplicate every fourth frame:

      SelectEvery(clip=clip, cycle=4, offsets=[0, 1, 2, 3, 3])

  In Python, std.SelectEvery can also be invoked by slicing a clip.

  If modify_duration is set the clip’s frame rate is multiplied by the number of offsets and divided by cycle. The frame durations are adjusted in the same manner.