At 09:04 AM 10/31/2006, [EMAIL PROTECTED] wrote:
>But still, the basic principle of video is still displaying a
>sequence of images (motion picture) with audio sync. Even with GOP,
>it is still displaying a sequence of images with full frame of first
>image, then display what's different on the second picture and onwards.
It's absolutely true that in the end video is always presented as a
series of images on the screen in sync with one or more audio tracks.
The difference is how those images are stored in a file, which all
depends on the compression scheme used (or not used). Each frame
could be stored individually, but it typically takes way too much
storage space which is why some compressions schemes use techniques
such as GOPs that only store intermittent full-frame contents. In
fact, some animation video could be stored simply as a set of
directions describing each object and how it will move over time.
We can't view the contents of those files directly, which is why it's
important that a decompressor or decoder reads the file and generates
a full sequence of frames, each with a full complement of pixels, to
present to the viewer. So in the end, as you point out, no matter
what the storage method we see a sequence of fully filled-in images
that flash on the screen quickly enough to give us the illusion of motion.
Mike Boom
P.S. As a piece of trivia, the reason we see a bunch of still images
as a moving image is that the human eye doesn't reset its sensing
neurons quickly enough to notice a series of distinct images if
they're presented quickly enough: typically 24 frames per second and
up. Many insects, on the other hand, have very fast visual sensors
and aren't fooled. That fly on the wall sees our video as a very fast
slide show.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/Adobe-Premiere/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/Adobe-Premiere/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:[EMAIL PROTECTED]
mailto:[EMAIL PROTECTED]
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
