I worked in VFX - so we were delivered the edited scenes and the artists would render on top of them ... theres very little post-processing done, what comes off

I worked in VFX - so we were delivered the edited scenes and the artists would render on top of them ... theres very little post-processing done, what comes off the farm is fit for the client. Although the farm schedules individual frames, they are combined into scenes (short clips from 2 - 30 seconds) and the artists get the scenes back. The scene file format is proprietary (and viewed with proprietary software), but I had a sneaky look inside and it seems to be losslessly compressed TGA frames. Scenes are usually short 2-6 seconds, and filesize would be 2-3 GB