I have heard that PNG is the best option when using videoclips with alpha channels. However, on my system ProRes 4444 seems to work better. I uploaded an example. All the clips where made in Apple Motion 4 and 5.
Do you also see the jerky motion with PNG, and the smooth motion with ProRes? My clips dont freeze, but they are very jerky with PNG. However, with ProRes I have to turn the resolution a little bit down, and sometimes it hangs up a little bit, especially when bpm is syncronized with the scratch button.
What do you make of all this?
http://dl.dropbox.com/u/443091/Test%201.zip
http://dl.dropbox.com/u/443091/Test%202.zip
http://dl.dropbox.com/u/443091/Test%203.zip