There is no denying that the interlaced format is the
earliest known form of video compression. As a matter of fact, it is developed
in order to address early TV technology challenges and broadcast bandwidth
constraints. However, interlaced video was not perfect enough to satisfy people’s
various requirements. Therefore, the progressive video was developed as a newer
technology which can help meet people’s requirements under specific conditions.
As for interlaced video, each field of a video image displays
every other horizontal line of the complete image. For instance, in the first
field of the interlaced video, the even-numbered lines will be displayed, and
then the odd-numbered lines of the same image will be shown with the second
field of the same interlaced video. If this even/odd sequence is repeated frequently
enough, for example, 25 to 30 times per second, then the viewer will be able to
see the complete moving image with the help of the persistence of human vision.
It is well known that the interlaced video allows more
detailed images to be created than would otherwise be possible within a given
amount bandwidth, which is its main benefit. As a matter of fact, a doubling of
image resolution is also allowed in interlaced video. However, there are also some
problems which cannot be ignored. In the first place, interlaced video comes
with real-world downside. On the other hand, image softening will take place
during fast-motion sequences. In addition, moiré or strobing artifacts are
likely to occur in the process of showing striped shirts, plaid jackets, bricks
in a building or similar types of objects.
In comparison with interlaced video, progressive video
has greatly gotten rid of such problems and thus enjoy more popularity among
people. It is possible that progressive video will play a more important role
than interlaced video in the future.
