Short answer – filmstrip (.flm) or image sequence in a folder (and run an action on a the folder PS)
If you can do it best or you’re more comfortable in Photoshop, then export the video into a form Photoshop can use.
In AE, with footage in the timeline, Ctrl M, brings up the Render Que.
Output Module > Custom (Brings up the Output Module Settings Box)
Format : Select – Filmstrip (my favorite, because it’s a single file and the effect goes on all frames in one shot)
or select one of the pic sequences (more people use Picture sequences for several good reasons (say a render crashes, you don’t have to start from the beginning, but I’m a bit overwhelmed by all those files generated and running a batch process on them, but that’s just me)
Import those into Photoshop, filter away, then re-import into AE. Filmstrips re-imported into AE come in as frames
in the timeline. It’s easier than it sounds.
The only draw back is that you can’t change the filter setting in PS (like keyframes in AE) unless you break the filmstrip of Image sequence into smaller bits.