aliasing on text : Adobe After Effects

hi there,

sometimes when i have a few effects like roughen edges on text i get a terrible aliasing like effect on the vertical edges. really noticeable steps.

is there anything i can do to get rid of this? or do you know what causes it?

cheers

Do you have Pixel Aspect Ratio Correction turned on? It can create horrible horizontal aliasing (which manifests as vertical lines), but these artifacts will only be present in the preview, not the final render. Disabling PARC will make these artifacts go away, but at the cost of the preview pixels being forced from their correct aspect ratio to square, which leads to the preview image being squashed or stretched.

thankyou. that makes it a lot better.

it's still there a bit but i think that's just down to resolution.

cheers

ok. further to this, i've just had a job sent back because of the jagged edges.

the text is a bold italic font and it's over a bright pink bgnd (nice!)

the text slightly moves forward using scale.

the edges are really breaking up. it looks like aliasing but on the off-vertical edges.

it's better on black but as soon as you put it on pink it looks dreadful.

my comp is D1/DV PAL widescreen. it looks bad on the mac monitor and on an lcd tv and a pal broadcast monitor. these 2 are being fed by a black magic card.

then render it out as a uncompressed quicktime and import into a smoke. it's then output to digibeta tape.

at all stages it looks equally crap.

can anyone help with this? i'm at a lose.

cheers

Having the extreme contrast of black on pink won't help the issue in any video format. Are you actually applying roughen edges? What other effects do you have on the text? If you disable them, does the text look sharp as expected?
And when you scale, are you scaling live type/vector type as opposed to a raster imported layer?

Can you post a still of the problem frame?

I'm not sure if this is really an aliasing issue. There are a few questions here:

- What kind of pink? If it's a pure red pink, naturally it will span the largest possible range in YUV space, meaning the contrast is probably going out of spec.

- What kind of text, how do you transform it what effect order (as laid out by the others)?

- Is the bold nature of the font created from a proper font contour, using faux bold or even worse, by applying layer styles/ effects to make it fatter?

Any of the above or combinations of them could cause the problems you are seeing. Also check for correct field order on rendering and any potential unmultiplied vs. premultiplied Alpha issues your application of effects may introduce.

Mylenium

thanks for the help guys.

I recreated the text in smoke with anti aliasing on and a bit of softness and then imported them into AE as 720x576 white on black stills.

I then put all the same effects on them and they looked so much better.

could you tell me how to post a picture here? and i'll stick one up.

the text is actually white on pink. the pink is RGB = 242,0,126.

the effects i'm using are sapphire glow, blur and lens flare. but the edges are just as bad with these turned off.

the text did look better on black and worse when the pink was introduced.

was using scale on the text layer. so it wasn't rasterised.

the text was a natural bold font, no faux bold etc.

also don't think it's a rendering thing as it looks bad while i'm working on it, looking at it on a PAL monitor.

thanks for the help. i'll post a pic when i find out how.

cheers

Sounds very weird. For pictures to appear, you'll have to host them externally, unfortunately, and post a link. Try photobucket or flickr. we sure would like to find out what's going on here.

Mylenium

the edges are really breaking up. it looks like aliasing but on the off-vertical
edges.





it's better on black but as soon as you put it on pink it looks dreadful.




You could be running into quite a number of things. Most likely it's the high contrast edge between the text and background (pink?) with the slow crawl that's making it sizzle (aka mosquito noise). Is it anything like this: <http://www.highdefinitionblog.com/?page_id=101>

A whole image blur may make it passable post quantization and compression.

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