Ah, square pixels, rectangular pixels, etc.... There are a ton of options. 720 x 480 is the MS DV size as well as the Sony Codec size. Certain products use 720 x 486. In Photoshop you can view the pixels as rectangular, even though Photoshop doesn't handle rectangular pixels. It helps keep things round. Carrara will render in rectangular pixels, too! I dont' have it open in front of me right now, but it's in the render settings. I think it's called "pixel aspect ratio." Set it to .9 for DV aspect ratio pixels. If you're rendering for DV Codec 16:9 widescreen, set it to 1.2. Hope that's helpful! - Dex