Hi marcpurcell,
If you have a video file, use it as it is. The downside of complete files is only that it occupies recourses.
To change that, load your file into a Ae Comp. Then go to AeCs4>Composition>Add to Render Queue
In the Output Module Setting chose Main Options>Format. Check other settings, but for a Background only, normally RGB is fine.
Alternative: In the C4D Picture Viewer, load in your movie file. Then Go to File>Save As. Chose: Type>Animation, Format>Photoshop, etc
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From a C4D scene, just to be complete: A PSD image sequence is like all other image sequences, You just set up the format in C4D (Render Settings). Please note that PSD is an option, but you might find other formats more suitable. It doesn’t matter.
What you should care about, that you do not use “Muti-Layer-File” option in the Multi-ass section. This will cause trouble in Ae, as it can’t be read fully. Ae can’t read anything else than RGBA files Color + Alpha max four channels.
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In Ae CS4 (as in newer versions) double click into the “Project” pane, or File>Import>File (or Multiple Files…)
Then select Enable: All Acceptable files.
Select the first (or any single file of that sequence) and the “Photoshop Sequence” will be active to be checked (or not) Alphabetical is most of the time not needed)
Click: Open
The Sequence that you have just imported has not fps assigned to, but Ae Cs4 will use the default, which might be not preferable.
In the left lower corner of the project window, you will find an icon called “Interpret Footage”. While your sequence is selected, click on this icon and adjust accordingly.
I have tested this in Cs4 just now, so I know it works with R16 PSD footage. iF there is any question, let me know.
Perhaps you check other formats as well. ;o)
All the best