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Alpha Channel not recognized

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John WhiteheadAlpha Channel not recognized
by on Jan 20, 2011 at 12:05:01 pm

Hi There

I have a bunch of Quicktimes that are Millions + PNG with straight alpha channel. I have checked the transparency in FCP - no problem there.

When I bring them in to AE the interpret footage dialogue box recognizes the alpha channel but when placed in a comp, or in a viewer they appear with a white background.

The comp background is set to black and I have tried the toggle transparency button - no luck there.

When exported out a test from the comp (RGB plus alpha) the result has a burned in white background.

I have run out of ideas and would greatly appreciate some help.

Many thanks in advance

John


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Dave LaRondeRe: Alpha Channel not recognized
by on Jan 20, 2011 at 5:51:54 pm

The only thing that comes to mind is that you don't have the free update to AE 10.0.1.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA


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Kevin CampRe: Alpha Channel not recognized
by on Jan 20, 2011 at 6:48:40 pm

if it's not the update, and there are no other effects on the footage or blending modes in the comp, or anything like that...

the only other thing i can think of is to try a different codec, or export just the alpha... if fcp can read the alpha, try exporting a lossless animation quicktime or image sequence that supports alpha, like tiff. or use fcp to export just the alpha. and see how any of those look in ae.

if they look as expected, then at least you've found the issue is specific to quicktime png and ae.

form a troubleshooting stand point it becomes easier, also you can submit a bug report.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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John WhiteheadRe: Alpha Channel not recognized
by on Jan 21, 2011 at 10:27:53 am

HI Kevin

I have done a bit of testing and discovered that if I export the supplied clip (PNG) from FCP, at it's current settings (PNG) THEN AE does recognize the alpha channel.

I find this a bit baffling as the clip has not been transcoded and the data rate remains the same the result seems to show no loss of quality so I guess it is a valid work around.

Incidentally my updater has taken my to 9.0.3.8 (CS4) is 10.0.1 CS5? If so presumably I would have to pay for that upgrade?

Many thanks

John


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Kevin CampRe: Alpha Channel not recognized
by on Jan 21, 2011 at 4:28:22 pm

[John Whitehead] "if I export the supplied clip (PNG) from FCP, at it's current settings (PNG) THEN AE does recognize the alpha channel."

yeah, that is a bit baffling... the only thing i can think of is that the original quicktime png file was created by a different version of quicktime (or at least it had a different version of that png component) and it doesn't play nice with ae for whatever reason...

re-exporting as png should not show any loss, png is lossless, so the extra step isn't hurting quality, just workflow.

as far as the 10.0.1 update, that is for cs5 and would be a paid upgrade. dave took a guess that you were on cs5, and that first update fixed a lot of issues with the original release.

Kevin Camp
Senior Designer
KCPQ, KMYQ & KRCW


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John WhiteheadRe: Alpha Channel not recognized
by on Jan 21, 2011 at 10:02:45 am

Thanks Dave

I am currently on 9.0.3 so I will try the upgrade

John


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