Choosing the right media

Before you start importing footage items into your project, decide which media you'll use for your finished movies. Then determine the best settings for your compositions and source material. For example, if you will be rendering your project to videotape, create footage at an image size, color bit-depth, and frame rate that will produce the best image quality on videotape. Likewise, if your project is intended for streaming video on the Web, the image size, color bit-depth, and frame rate may need to be reduced to work with the data-rate limits of streaming video on the Web. However, any footage item that can be imported can be used in any composition.

If you will be rendering a project to more than one media format, always match the resolution setting for your composition to the highest resolution setting used for your output. Then set up the Render Queue window to render a separate version of the project for each format.

For film and video, try to match import and composition settings with settings in the output module used to render a movie. For example, to ensure smooth playback, the footage frame rate selected in the Interpret Footage dialog box should match the setting in the Composition Settings dialog box and the output module in the Render Queue window. Also, the composition-frame size should be determined by the image size in the playback medium. However, any footage item that can be imported can be used in any composition. See Preparing motion-footage frame rates for final output, Understanding basic composition settings, and Changing output module settings.

If you will be mixing source footage with different pixel aspect ratios, correctly specify this ratio for each footage item in the Interpret Footage dialog box. See About D1, DV, and various pixel aspect ratio footage.

The suggestions that follow will help you select composition settings. However, the best way to ensure that your project is suitable for a specific medium is to make a test composition and view it using the same type of equipment your audience will use to view it.

Film

If you will be rendering for film, consider both the aspect ratio of the frame size you select for your composition and the frame rate of your source footage. For footage that was transferred from film to video using the 3:2 pulldown telecine method, you must remove 3:2 pulldown before adding effects. See Removing 3:2 pulldown from video transferred from film.

CD-ROM

When you create a movie that you plan to render for playback from a CD-ROM, you may need to specify import and composition settings that take into account the wide range of hardware that your audience may be using, possibly including older single- or double-speed CD-ROM drives.

To make your final output compatible with older CD-ROM drives, try to reduce the data-transfer rate of your final output by specifying certain settings for footage items:

• Lower the frame rate as far as you can in the Composition Settings dialog box without making motion seem too jerky. Start at 15 frames per second (fps).
• When rendering your final composition, choose a file type and compressor/decompressor (codec) appropriate for the final media. For example, for a cross-platform CD-ROM, you might specify a QuickTime codec or a codec designed for low data rates, such as Indeo, Cinepak, or Sorenson Video. Regardless of which codec you select, however, it must be available on the system used by your intended audience to ensure successful playback. Also consider the key frame rate of the codec you have selected. See the Adobe Web site for more information on QuickTime compressors and codec key frame rates.

Videotape

If your final output will be videotape, set up your composition with a specific video format in mind, such as NTSC or PAL. Using broadcast-safe colors and maintaining frame size and compression ratios are also important considerations. These guidelines will help in setting up a composition intended for videotape:

• Select a frame size in the Composition Settings dialog box that matches the frame size of the destination video format.
• Use only NTSC-safe colors when adding or changing color in a project.
• If you will be using an MJPEG codec, keep in mind that the frame sizes and resolutions available for rendering are determined by the specific MJPEG board you are using. Refer to the specifications for your MJPEG board.

Animated GIF

When you render an animated GIF, colors are dithered to an 8-bit palette. Before rendering your final project, render a test composition so that you can adjust colors if the results are not what you expected. If any source footage includes an alpha channel, be sure that you know how it will affect your final project before you start rendering.

Streaming video over the World Wide Web

Streaming video resembles a conventional television signal in that video is sent to the viewer frame by frame, instead of by downloading a large file to the hard disk. Streaming video on the Web is constrained by the limited bandwidth (56 Kbps or less) of most consumer modems, which is even lower than those used for CD-ROM playback. Use the same techniques that are listed for CD-ROM playback, but adapt them for further reduction in file size and data-transfer rate. You can export QuickTime streaming directly from After Effects. See Exporting footage using QuickTime components.

Downloading video over the World Wide Web

If your final output will be downloaded as a file from the World Wide Web, the main concern is the size of the file, which directly affects how long it takes to download the file. QuickTime and Microsoft Video for Windows are formats often used when rendering final output that will be downloaded. When you render a QuickTime movie, After Effects automatically creates a movie that can play on both Windows and Mac OS without modification.

Intranet playback

An intranet is an in-house or private network that uses Internet network protocols. Intranets generally use higher-quality communications lines than standard telephone lines, so they are usually much faster than the Internet. The data-transfer rate for playback can be 100K per second or faster, depending on the speed of your intranet.

Flash (.swf) files

When you export compositions as Flash (.swf) movies, After Effects maintains vectors as much as possible. However, some items cannot be represented as vectors in the Flash file. See Exporting to Macromedia Flash (SWF) format.