DV compression
 

Recording in the DV format automatically compresses the video 5X...so if you build a DV sequence in After Effects and then lay it off to DV tape and re-import into your editing project, you're incuring another 5x compression, yes?

So it's better to export from AE to an .avi file and re-import? This doesn't involve another round of compression?

No, it is not necessarily compressed again. If it is already in DV format then it is copied from the tape to the hard drive. If you copy a jpeg photo from a zip to your hard drive is it expanded then compressed again. No. The data is moved, intact from one location to another. If changes are made to the file, add filter, title, effects etc. and rendering occurs then it is compressed again.

Jeff

Jeff is correct... There is no recompression. The only thing might
be that you get dropped frames or errors in your files due to the
nature of tape (unlikely, but could be).