I'm doing a key in HD 1280 in AE CS3. When I am keying it I get stair edges for some reason. I've tried to interpret the footage but i can't seem to find any solution to it?
anyone?
Re: stair edges when keying? by Kevin Camp on May 28, 2008 at 2:04:22 am
what are the dimensions of your hd footage... 1280x1080, 1440x1080 or 1920x1080...?
if it is anything other than 1920x1080, try creating a new comp that is 1920x1080, square pixels and the frame rate of your footage. then drag your footage into that comp... do the jaggies go away?
if so then the problem was ae's pixel aspect ratio correction preview that caused the jaggies. those artifacts will not show in your final render, they are just a quick way for ae to stretch the image on a square pixel computer monitor. you can toggle the pixel aspect ratio correction on and off for previews (it's the icon that looks like a rectangle with and arrow above it).
Re: stair edges when keying? by Kevin Camp on May 28, 2008 at 5:22:30 am
ok, the pixel aspect ratio correction may still be part of your problem... 960x720 hd footage has a pixel aspect ratio of 1.33 (meaning that it is one third taller than it is wide) and will looked squished with the pixel aspect ratio correction turned off.
try creating a comp that is 1280x720, square pixel and the same frame rate as you footage. drop you footage into that comp. do things look smooth in the square pixel comp?
if so, great, you can continue to work in the square pixel hd comp, or if you wanted you can work in the native footage comp size (960x720, 1.33 p.a.r.) just know that the jaggy preview is just the preview, your render will look nomal back in your nle.
if not, then it may be another problem, like incorrect field settings for the footage. to fix that you'd like to know if the footage you have was shot progressive or interlaced, then, with the footage selected in the prject window, choose file>interpret footage>main. find the separate fields option and make sure it is set to the correct settings (off, lower or upper).
