does it make any difference in terms of quality which source I use to airplay the material on my tv?
if the shows are downloaded ...
From the iTunes store, no it doesn't
... make a differnece
if you've downloaded from the iTunes store, then your computer or you ipad is only acting as a file server. If everything is
set up correctly, then your ipad and your computer should have the same file
if you...
1. play a move on your ipad, and airplay it to the aTV
2. play a movie on iTunes on you computer, and airplay it to the aTV
3. using the computers section on your aTV to browse the iTunes library on you computer.
it's all playing the exact same file so the quality would be the same.
examples of things not being set up correctly...
*not set to download HD videos (or an older device that can't)
*using airplay mirroring (if you see the movie on your iPad/computer screen, you're doing it wrong)
the only difference you might see is network related, if your computer is wireless and at the other end of you house with a poor wi-fi signal, you could see stuttering or longer buffer times.