Rendering is the creation of the finished frames of a movie from a composition. The rendering of a frame is the creation of a composited two-dimensional image from all of the layers, settings, and other information in a composition that make up the model for that image. The rendering of a movie is the frame-by-frame rendering of each of the frames that make up the movie. For more information on how each frame is rendered, see Render order and collapsing transformations.

After a composition is rendered for final output, it is processed by one or more output modules that encode the rendered frames into one or more output files.

A movie can be made into a single output file (such as a Flash Video movie) that contains all of the rendered frames, or it can be made into a sequence of still images (as you would do when creating output for a film recorder).

Though it is common to speak of rendering as if this term only applies to final output, the processes of creating previews to show in the Footage, Layer, and Composition panels are also kinds of rendering. In fact, it is possible to save a RAM preview as a movie and use that as your final output. (See Preview video and audio.)

To see a video tutorial on rendering and exporting, visit the Adobe website at www.adobe.com/go/vid0262.

After Effects provides a variety of formats and compression options for output. Which format and compression options you choose depends on how your output will be used. For example, if the movie that you render from After Effects is the final product that will be played directly to an audience, then you need to consider the medium from which you’ll play the movie and what limitations you have on file size and data rate. By contrast, if the movie that you create from After Effects is an intermediate product that will be used as input to a video editing system, then you should output without compression to a format compatible with the video editing system.

In the Render Queue panel, you can manage several render items at once, each with its own render settings and output module settings. Render settings determine such characteristics as output frame rate, duration, resolution, and layer quality. Output module settings—which are applied after render settings—determine such post-rendering characteristics as output format, compression options, cropping, and whether to embed a link to the project in the output file. You can create templates that contain commonly used render settings and output module settings. Using the Render Queue panel, you can render the same composition to different formats or with different settings, all with one click of the Render button:

• You can output to a sequence of still images, such as a Cineon sequence, which you can then transfer to film for cinema projection.

• You can output using lossless compression (or no compression) to a QuickTime container for transfer to a non-linear editing (NLE) system for video editing.

• You can output to H.264 or another highly compressed format for playback on mobile devices such as cellular phones or the Apple iPod.

• You can output to MPEG-2 for playback from DVD.

If you output your movie in the H.264 format for mobile devices, then you can use Adobe Device Central to view your movie as it will appear on any of a large number of mobile devices. Adobe Device Central emulates cellular phones, portable media players (such as the Apple iPod), and many other common viewing devices. (See Preview a movie on a virtual mobile device using After Effects.)

Rendering a composition into a movie can take a few seconds or many hours, depending on the composition’s frame size, quality, complexity, and compression method. As After Effects renders the item, you are unable to work in the program. An audio alert indicates when rendering is complete.