I have some RED footage shot 2.40:1. I brought it into After Effects, created a composition from selection and exported it. When I bring the exported quicktime back into After Effects it is the correct frame size, 2048x854. But when I view it in Quicktime Player or Avid the file opens 1920x1080 and looks stretch. When I view the quicktime properties in Avid, the source footage's Image Aspect Ratio is 2.40:1, but the After Effects Export says the Image Aspect Ratio is 16:9.
Can someone please help, I want to export from After Effects at 2.40:1, why isn't it maintaining this ratio?
What codec are you using when you render?
DNxHD 1080 220 10-bit. I switched it to ProRes and it worked!