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Filed under: Editing •Motion Graphics •Post Production •

Open Wide: Creating That Widescreen Look

In an ideal world, our applications would handle the stretching and squishing for us automatically - after all, most video software today can deal with the slight anamorphic stretch required to handle DV and D1 video frames, which has more pixels across (720) than we need to describe a 4:3 aspect image that’s only 480 or 486 lines high. Indeed, most DV systems now tag and properly decode footage that was recorded widescreen. However, some older software doesn’t know how to deal with widescreen, and even when new software does, it doesn’t always display it on the computer monitor stretched back out to the width it would be seen during playback - it just shows it in its squished format. Things get even more confusing when you want to combine non-squished elements such as 4:3 video, still images, or vector art with your anamorphic video.

One working practice is to use a normal D1/DV size composition or workspace, but to make sure its pixel aspect ratio is tagged as being widescreen. When you add widescreen footage in, it should still look squished. When you drag in type or other square-pixel elements, they should look squished in this composition - this is the result of the anamorphic squeeze being applied to them. Do not try to out-smart your software by setting the pixel aspect ratio of your normal, square-pixel elements to be widescreen; your software will not know it has to treat them different than your widescreen footage.

This distortion can be a bit odd to work with. As a result, when working in a compositing or graphic program such as Adobe After Effects many prefer to work at what would be a square pixel widescreen size, rather than the squeezed anamorphic size. To do this, create a composition that is 486 lines x 16 units ÷ 9 = 864 pixels wide. Your software should allow you to tag your widescreen video as such (for example, use the Interpret Footage dialog in After Effects, and set the Pixel Aspect Ratio option accordingly), and as a result automatically stretch it out to this width for you in your 864-wide comp so it looks normal on your computer screen. If it doesn’t, you can stretch to fit manually (technically, by 121.2%, although most will use 864 ÷ 720 = 120% based on the common misperception that all 720 pixels are supposed to contain visible image).

Make sure this composition is set to use a square pixel aspect ratio, not D1/DV or widescreen. Treat all of your other elements as you did before, and mix them to your heart’s content - they should look normal. When it comes time to output back to widescreen, you need to squeeze the width of your composited image back down to 720 pixels wide. In After Effects, you can do this in a second composition, or using the Stretch option in its rendering Output Module. This chain is shown in Figure 2. The rendered movie will look squished horizontally, but a widescreen display will stretch it back out to its proper width.

When creating anamorphic widescreen imagery for a standard-definition DVD, plasma screen playback, and the such, we often work at the corresponding square pixel size. Workflow ideas are discussed in more detail in our more recent column Non-Square Strategies.

sidebar: More Anamorphic Math

If you want to work at a natural square-pixel widescreen size for NTSC video, the math works out to 486 pixels high x 16 units wide ÷ 9 units high = 864 pixels wide. If you are working in 480 pixel high DV, the width should still be 864 pixels. DV should be thought of as D1 video with six lines missing - the pixel and image aspect ratios are otherwise the same. For PAL, the math is similar, merely with different numbers plugged in: 576 lines x 16 ÷ 9 = 1024 pixels wide.

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