After Effects v22.3.0 DNxHD Alpha render broken.
When rendering to DNxHD on 22.2.0 with an alpha channel, under format the options are None or Uncompressed. Both options work. On the latest release, the options are None or Compressed, if you choose compressed, no alpha channel is created, making it useless for creating titles for Avid. This needs to be3 fixed immediately.
Please see the following article for information about changes to DNxHD in After Effects 22.3: https://community.adobe.com/t5/premiere-pro-discussions/announcement-changes-to-quicktime-dnxhd-support-in-premiere-pro-22-3/m-p/12905939#M408114
John Cuevas commented
Sorry for the time to get back, been very busy. Attached is a AE project where I exported a two DNxHD with compressed alpha channels. When I import them into Avid, Avid says it's importing an alpha channel, but all I get is the fill channel, no alpha information. If I link the file, the alpha information is there.
Bringing the files into AE, I get the correct alpha channel. I'm working with the newest Avid release: Version: 2022.4.56108
I've attached the AE project and my first render. Please feel free to contact me for more information.
We did indeed do some work on the Avid DNxHD output options and that is why you see "Compressed" now - the way alpha is now written to the file, per Avid's guidance, is compressed so we updated the UI. That said, if you aren't seeing alpha in your output that is most concerning and I would like to help you get to the bottom of it. When you say the resulting file has no alpha are you checking the file in Avid, After Effects, or both? Also would it be possible for you to share your output settings and possibly a sample export that doesn't have alpha?