View Full Version : Problem with After Effects Alpha Channel


John Rich
August 28th, 2008, 04:08 PM
I am using Aspect HD5.2.5.109 build from March 4,2008.

I have AE CS3 and trying to make a lower third type graphic, by masking out the background image and moving mask etc. but when I do this, there is no alpha channel.

When I render it Video Windows for Movie using the Cineform HDCodec V3.6.2, and setting Channels to RGB + alpha, the clip renders, but includes the background of the comp, ie there is no alpha channel.

I repeated this a couple of times and it still happens. The comp is using a HDV 1080 29.97.

I hope this is something simple I'm doing wrong. Thanks in advance for the help.
John Rich

David Newman
August 28th, 2008, 04:57 PM
Most compressed codecs don't support alpha channels. Aspect HD codec doesn't. However the Prospect 4K or NEO 4K version of the CineForm codecs does support alpha channels and 4:4:4:4 encoding. You can download a 15-day try of either product to see if you like it.

Steps
1) Uninstall Aspect HD (do not deactivate)
2) Install Prosect 4K
3) have fun for 15-days to see if you want to upgrade.
4) Either purchase an upgrade, or uninstall P4K and reinstall AHD (there are no licensing issues doing this.)

John Rich
August 28th, 2008, 06:10 PM
Thanks David,

I read that after I posted, on another thread. That's kind of disappointing. I really don't want to up grade.

I guess I need some kind of work around. I was using the Cineform Premiere Pro CS3 preset, for my Premiere Pro Project and I rendered the graphic out of AE as a quicktime mov, but I got an error message when I dropped it onto my Premiere timeline.

I tried using the Premiere HDV 1080 30p project and imported the Cineform clips I had downloaded with HDLink and used the quicktime .mov lower third which worked ok in Premiere. Then I exported this using Export - Movie - and used the Cineform HD codec as 720x480 1.2 Aspect ratio and Progressive, and it looks good on Windows Media Player.

My original footage was HDV captured from a HV20. If there is a better way to do this, I would appreciate any help. Thanks,
John Rich