So, update:
I have not yet had a chance to troubleshoot by connecting my MBP to the Samsung and playing the same movie (need to locate some cables).
However, in the meantime -- I received a Roku XS for Christmas. The same movie, played on the Roku (over a G network no less, where the ATV was on N), is noticeably smoother than when played through the ATV. So, I'm pretty much convinced it's not the way I'm ripping these, and the TVs seem to be capable. Guess maybe I just need to wait until Apple has a 1080p native AppleTV, or something.
I have not yet had a chance to troubleshoot by connecting my MBP to the Samsung and playing the same movie (need to locate some cables).
However, in the meantime -- I received a Roku XS for Christmas. The same movie, played on the Roku (over a G network no less, where the ATV was on N), is noticeably smoother than when played through the ATV. So, I'm pretty much convinced it's not the way I'm ripping these, and the TVs seem to be capable. Guess maybe I just need to wait until Apple has a 1080p native AppleTV, or something.