AE added support for .swf files awhile back, these are imported as raster graphics, which is ok, but it is possible to import Flash movies into AE as vector objects, and this To prepare a movie in Flash for use in an AE comp, you will want to set the movie dimensions to match your project in AE. When the Flash files are imported into AE the positioning of all elements will then be correct in relation to the comp (same function as crop marks in Illustrator). Flash is frame based, so the frame rate you set is not important, but you do want to use the frame rate of your comp as a guide in creating the animation. Flash will export one file for each frame. It may be helpful to save an image of the comp from AE as a jpeg, and import this into Flash to use as a background guide for positioning elements. Use all the regular Flash animation tools, motion and shape tweening, transformations, etc. will save the movie as x.fla, save as many copies of the movie as needed under different names. To export the movie as separate layers, delete the unwanted layers from each copy, and export each .fla version individually. The movie is not exported as a .swf file, but as a sequence of EPS files. Go to file>,export movie, select save as type, EPS 3.0. Give the file a name that does not end in a number, as this will cause problems for AE. When you save the movie, Flash will create a sequence of images numbered from the first frame, x0001.eps, x0002.eps, etc. In AE file>,import>,file, navigate to the folder, select the first file in the sequence, import as footage, and click the check box ‘generic eps sequence.’ With the file selected in the project select antialiasing>,more accurate. Now drag the file into the comp, and scale, set transparency, adjustment layers, etc. as needed. To apply filters, the vector layers must first be precomposed. change hue and saturation (does not require precomposing), or creating a solid layer the color you want, and setting the vector layer as a track matt. When the .eps files are imported, AE creates an alpha channel for them, making the background transparent. Also some fonts used in Flash might not be recognized by AE. The solution is to break apart the text symbol in Flash, and in will import into AE correctly as a vector object. Everything here relates to my use of a PC. The possibilites here are tremendous, both Flash and AE are great programs, and being able to add the strengths of one to the other is pretty exciting. I’m just getting started with this, so interested to learn more. Source.