Serrated edge artifacts

osiase wrote on 3/13/2002, 10:15 PM

I ran into a problem with my latest project that I have not encountered before. The problem is a large amount of what I call "serrated edge artifacts". The edges of moving (and non-moving panned objects) objects have ghosts that are "serrated". The artifacts appear most on objects that are contrasted against the background (white against dark as well as dark against white). This problem appeared on my footage of students in a Martial Arts school; however I reviewed my footage of an indoor skating rink the week prior and saw no artifacts on the skaters. The lightening was similiar in both places. I use a Sony DCR-TRV30 mini-DV. The problem appears when I capture in both in VV3 (DV codec) and Premiere 6.0 over a IEEE-1394 firewire; so I assume the source of the problem is in the filming and not the firewire capture process. The problem does show up in the captured footage when viewing in the preview window at both PREVIEW and BEST setting including PROJECT and non-PROJECT size; as well as the rendered video (DV, .wmv and MPEG-1).

My question is, what causes this artifacting? how can I avoid it during filming? and more pertinent to this forum, is there any track FX in VV3 that I can use to compensate for this problem? if laying the cash for a 3CCD camera is the answer, please let me know.

Comments

Cheesehole wrote on 3/14/2002, 6:21 PM

sounds like you are seeing interlace lines to me. when you view an interlaced source on a non-interlaced device, such as a computer monitor, you can see the interlaced lines, especially on fast moving objects with a high contrast background color. you shouldn't notice this on a TV though. when you view the footage on a television is the problem there?

if your camera has the capability you can shoot in progressive mode to eliminate the problem. 3CCD isn't going to help, but a progressive scan CCD will. not the kind that are in most consumer Sony's, because they only do 15fps in progressive mode, but the kind in Canon GL-1/XL-1 and some others... which does 30fps progressive. it's great for those high-action scenes especially if you do any freezes or grab any stills from your video.

otherwise there are some settings and filters in VV to help with that and maybe someone else can chime in for that?

also, if they are really bad, then it may be that your fields are switched somehow. try changing the field order of your source clip properties and see if that helps. if they are switched the wrong way, things will be real screwy.

- ben (cheesehole!)