digital artifacting?

ditnoj wrote on 12/30/2004, 8:34 AM
Hello.
I am doing some searches on this site and on the dvdoctor site but I want to make sure that I am on the right track.

I am experiencing in my videos
1. color "bleeding" (I'm not sure of the video term, but since I'm audio-bred, I'll use that term) from one part of the frame to another. Such as a person with a red hat on and I see some red in other places in the frame where it shouldn't be.
2. an effect that looks like active "digital brushstrokes". It seems to be worse when there is movement but not always. In one particular shot of a woman talking, her face is fine (except for the red from her hat!) but her neck has the effect that I'm referring to. There is also another shot in a church with red carpet that has bleeding and "brushstrokes"

Is this second thing what is referred to as "digital artifacting"?

Now I believe that at least part of this is due to not the best equipment. All of what I am editing was shot on HI 8 and Digital 8 (relatively inexpensive samsungs). Also, most of the shooting was done by totally untrained folk. (I'm about 1 or 2 steps above that!)
The capture was done via Studio 8 through a Dazzle *80. Editing on Vegas 5 on a Sony Vaio lap (P4M, 512, external 7200 250G, XP pro).

What I'd like to know is
1. Are my conclusions relatively on point?
2. Are most of these issues equipment (camera, capture card) based.
3. Where do I start to correct (learn how, or search) some of this with my existing equipment (I am starting to twiddle with the adjusments on the encoder in Vegas. When I shoot I am trying to stay away from camera movement. Obviously as soon as possible I will get a decent camera...actually I don't even own one yet! like I said, I'm audio-bred)

Any constructive advice is appreciated!

Thanks in advance!

D out ITNOJ

Comments

Chienworks wrote on 12/30/2004, 9:28 AM
Problem 1 is most likely due to DV color sampling, which throws away color detail. You can end up with blocky edges on curves and diagonal lines. The effect is worse with reds. It shouldn't bleed more than a few pixels though if this is the problem. There isn't much you can do about it except shoot under good lighting and avoid strong color contrasts.

Problem 2 is probably interlacing. Analog video records two fields for each frame. Each field consists of every other horizontal line of the image and are delayed half a frame apart, timewise. If you have someone moving rapidly horizontally across the screen then the first field will capture them in one location and the next field will show them in a different spot. This is fine when playing back on standard TV type monitors because the fields will be played back the same way they were recorded. However, most computer monitors are non-interlaced and both fields are played back at exactly the same time. Because of the movement, the two fields contain substantially different images and you'll get the "comb" effect. This shouldn't be noticeable when played back on a television. If the problem is still visible on a TV or you need to play it back on a computer monitor you can "de-interlace" by several methods. A quick search in the help file for "de-interlace" should show you all you need to know.