A method of detecting a change in a sequence of video data fields
generated from a progressive scan source includes receiving first and
second interlaced fields of a corresponding progressive scan frame from a
sequence of interlaced fields generated from progressive scan source.
Pixel values corresponding to pixel positions of pixel lines of a first
parity of the first field are weaved with pixel values corresponding to
pixel positions of pixel lines of a second parity of the second field.
For each pixel value corresponding to each pixel position of each pixel
line of the second field after weaving, a check is performed for the
corresponding pixel position for feathering due to motion. A number of
detected pixel positions with feathering due to motion is counted and
compared against a threshold. A determination is made that the sequence
of fields generated from the progressive scan source has not changed when
the number of counted pixel positions due to motion is below the
threshold and a determining that the sequence of fields generated from
the progressive scan source has changed when the number of counted pixel
positions due to motion is above the threshold.