Jaggies

newUzer wrote on 6/6/2005, 6:55 PM
Hello,

I've started to experiment with green-screening and it looks pretty good in the preview panel after brightness/contrast and threshold/blurring are adjusted. When I render it using default DVDA3 settings and then use DVDA3 to create a test DVD, however, I notice a lot of jaggies (more like blocks) around the content on the keyed track. The project is widescreen and the chroma-keyed track is derived from a sony handycam in 16:9 mode. Any thoughts on how to get rid of the artifacts?

Comments

PeterWright wrote on 6/6/2005, 7:31 PM
When you say "DVDA default settings" do you mean the "Default Template" in the Template settings? If so, this is probably the cause - the bit rate is set at a video quality of 15 on a scale of 31.

The DVDA settings are much better. If you are already using these, it's something else .....
Spot|DSE wrote on 6/6/2005, 7:34 PM
First, since it's a HandyCam in wide mode, you're really only seeing 75% of resolution based on the way widescreen is derived in those smaller format cams. So the resolution is already less than ideal. Also, it's DV, which can be challenging unless the screen is properly lit and subject away from background.
You might try using the Chromablur in Vegas to help. You can see a good tutorial on Chromablurring at
http://www.vasst.com/resource.aspx?id=4fd2419c-8ed5-4cb0-8abe-9bb656287c31

This will help during the encode to MPEG, even though you're working with a few different colorspaces in the process. Can you preview this externally before rendering to MPEG? That'll help you better see if the key is aliasing or not.
newUzer wrote on 6/7/2005, 1:03 PM
Although I'm not in front of the app right now, I believe I chose mpeg2, widescreen DVDA video stream, and made no custom changes. Does this explain the outcome?
Spot|DSE wrote on 6/7/2005, 1:46 PM
It likely isn't a product of the mpeg encode, but more likely a product of your chromakey and monitoring tools/workflow.
If you don't view this externally first, and are only looking at the computer screen, then viewing in a player or on a TV from a DVD, you'll never have a real clue in the authoring/editing process as to what you're creating.
Keying on a computer only is very challenging.