We have just upgraded all our kit to work in full HD and i have just tried exporting an animation of a countdown clock from AE CS5 to Avid as a TGA sequence with an alpha channel. This is the way which i always used to get footage with an alpha channel across to the editors when we worked in SD and the file size was never that large nor did i have to wait an excessive amount of time for it to render. However the 2 1/2 minuet clip took nearly an hour to render on my new machine and ended up being nearly 30GB in size.
Anyone have any tips on the format they use to export alpha channels to avivd without taking up too much room, and a little bit faster than this. Any tips for non aplha channel exporting wont go a miss either.