Hello. I imported a 1440x1080 Pro Res video file into AE and then dragged that file onto the new comp button to create a new composition for it. The resulting composition (1440x1080) however is not widescreen and plays back poorly. The same file displays properly and plays back fine in Premiere Pro, FCPX and Motion. Is there a setting for non square pixels that needs to be set in AE? Would that cause the comp to stutter and not playback audio?
I apologize for the basic question. After posting this I found out that I needed to toggle on Pixel Aspect Ratio Correction. Now the comp looks right. Playback is still slow however for parts of the comp not in RAM preview. I eventually want to use the rotobrush tool to create a mask. Since increasing the amount of RAM in this machine is not an option would a good workflow be to create a proxy or playback at lower resolutions? Does the lower resolution of a proxy file hamper the rotobrush tool's ability to properly detect edges?