Fixed in Vuo version: 

How severely does this bug affect you?: 

●●○○ — It's annoying but I can work around it.

Steps causing the bug to occur: 

  1. Load prores media into decode movie image
  2. Playback composition with generator protocol
  3. Regardless of HDD speed (I am using fast SSD) playback is very jerky and not realtime
  4. Using large media makes situation worse (such as 4K)
  5. Same media plays back easily in FCPX or other media player