Video Compression...

[Eberlini]

In my Director project, I have some 640x480, 30fps Quicktime videos embeded.
I've tried adjusting many of the Sorenson compression settings...I get this
annoying problem everytime. The video will look like it's having refresh
problems (lines that separate frames of action.) It's quite bizarre
really...I've tried insanely small bitrates and the problem still persists. It
only happens during some quick camera pans. I'm quite familiar with the whole
interlacing /de-interlaceing thing...that doesn't seem to be the problem.

I was just wondering if there was anyone else out there that had simliar
problems occur, and what they did to correct them. Since it only occurs during
quick camera motions, is it unavoidable?

[Doug Golenski]

Try compressing it at 320X240. Then open the file in QT Pro and choose
"Double Size" for playback then save the file. Quick pans don't do well in
digital video (unless you use MPEG 2...DVD), the best you can hope for is to
minimize the artifacts. BTW, using too low of a bit rate won't help
things...try 360 kilobits per second (not Kilobytes per second).

hth,
Doug
"Eberlini" <webforumsuser@macromedia.com> wrote in message
news:c6p7cb$hj6$1@forums.macromedia.com...

> In my Director project, I have some 640x480, 30fps Quicktime videos

embeded.

> I've tried adjusting many of the Sorenson compression settings...I get

this

> annoying problem everytime. The video will look like it's having refresh
> problems (lines that separate frames of action.) It's quite bizarre
> really...I've tried insanely small bitrates and the problem still

persists. It

> only happens during some quick camera pans. I'm quite familiar with the

whole

> interlacing /de-interlaceing thing...that doesn't seem to be the problem.
>
> I was just wondering if there was anyone else out there that had simliar
> problems occur, and what they did to correct them. Since it only occurs

during

> quick camera motions, is it unavoidable?
>

[JB]

Different codecs have different artifacs, the more advanced squeezers
like sorenson rely heavily on temporal ( frame differenc) compression,
scene changes and fast motion cause a spike in data rate, or a drop in
quality depending on compression settings. I thnnk variable data rate
compression (like sorenson pro?) will up te data rate, throwing in more
key frames as neededto preserve quality. Another stragety to consider
to get a smaller fle size and data rate is to output the video at 15
fps, effectlvely halving the data requirement.

Speaking of wierd artifacs, DIVX can really go wrong when things get out
of sync.