AfterEffects

Test field-rendering order

When you render a composition containing separated footage, set the Field Rendering option to the same field order as your video equipment. If you field-render with the incorrect settings, the final movie may appear too soft, jerky, or distorted. A simple test can determine the order in which your video equipment requires fields.

Note: The field order might get altered if you change the hardware or software of your production setup. For example, changing your device control software or VCR after setting the field order can reverse your fields. Therefore, any time you make a change to your setup, test the field-rendering order.

The test takes about 15 to 20 minutes and involves creating two movie versions of the same composition (one rendered with Upper Field First and one with Lower Field First), and then playing the movies to see which choice looks right.

  1. Create a simple composition with the correct frame size and frame rate. Choose an NTSC or PAL preset in the Composition Settings dialog box, and make the composition at least 3 seconds long.
  2. Within the composition, make a layer that is a small rectangular solid. The layer can be any color as long as it contrasts sharply with the composition background. You may want to add a title (such as “Upper Field First”) to the solid to make identification of the movie easier.
  3. Apply some fast movement to the solid using keyframes in its Position property. Set keyframes from the upper left of the Composition panel to the lower right for 1 second.
  4. Save the project, and then drag the composition to the Render Queue panel.
  5. Click the underlined Render Settings name, and then choose Upper Field First from the Field Render menu.
  6. Click OK, and then click Render to make the movie.
  7. In the composition, change the color of the solid in the Composition panel, and add a new title, such as “Lower Field First,” to identify it.
  8. Render the composition again, choosing Lower Field First from the Field Render menu in the Render Settings dialog box.
  9. Record both movies to the same device.
  10. Play both movies.

    One movie will look distorted and have jumpy horizontal motion or shape distortion during vertical motion. The other movie will play back smoothly, with sharply defined edges. Use the field order for the smooth-playing movie whenever you render movies with that particular hardware configuration.