Selecting a Codec

When you choose to export an animation sequence as an AVI or a QuickTime movie, one more dialog box appears after you name the movie file in the File dialog box. The Video Compression dialog box, shown for AVI in Figure 35.3 and for QuickTime in Figure 35.4, lets you select, specify, and configure the codec that is used to compress the video.

Figure 35.4. QuickTime Compression Settings dialog box.

[View full size image]

A codec is a piece of code that is used to compress the unused bits of data in the video to make it a more reasonable size. Codec works in video just like the MP3 format works in music. Some codecs allow video frames to be compressed losslessly and others use a lossy method to compress the data. A lossless method of compression maintains the same quality as the original video frames whereas the lossy method works to reduce the size more aggressively by removing some of the original pixels.

The Compression Settings dialog box, whether you are using AVI or QuickTime, has a number of codec options available from a drop-down list. Some of these codecs are common among a large variety of software packages such as Cinepak, DV, Intel Indeo, MPEG, and Sorenson Video. Others are more specialized.

The Compression Settings dialog box also includes options to set keyframes every designated number of frames. These video keyframes record the entire screen data and nonkeyframed frames record only the changes between the keyframed frame and the new frame. This causes the keyframes to be rendered with minimal compression.

The Limit Data Rate setting specifies the size of the video file per second. The specified size is dependent on the size of the final video, its frame rate, the selected codec, and the complexity of the project. As a general rule of thumb, try using these settings if you intend to stream your video over a network or the Web:

• Full HD at 1920 by 1080: Use a data rate of 7,000 to 9,000 Kbyte/sec.

• NTSC-widescreen at 1280 by 720: Use a data rate of 5,000 to 6,000 Kbyte/sec.

• Standard resolution at 640 by 480: Use a data rate of 1,000 to 2,000 Kbyte/sec.

• Web resolution at 320 by 240: Use a data rate of 300 to 500 Kbyte/sec.

• Mobile resolution (3G) at 176 by 144: Use a data rate of 150 to 200 Kbyte/sec.

After a codec option is configured and selected, the exporting process begins, and the rendered project frames are displayed in the progress window, shown in Figure 35.5. When the video is complete, it is automatically opened and played in the default media player.

To export a project using the AVI format, follow these steps:

1.	Open the Spinning logo.anme file from the Chapter 35 folder on the CD. This file is taken from an earlier tutorial and features a spinning logo.
2.	Select the File, Export Animation menu command (Ctrl/Cmd+E). In the Export Animation dialog box, select the Antialiased edges, Apply Shape Effects, Apply Layer Effects, and the Render at Half Dimensions options. Then choose the AVI Movie option from the Output Format drop-down list and click the OK button.
3.	In the File dialog box that opens, give the export file a name with the .AVI extension and choose a location; then click the Save button.
4.	In the Video Compression dialog box, select the Cinepak Codec by Radius option from the Compressor drop-down list. Drag the Compression Quality slider to 75 and click the OK button.
5.	After the export process is completed, the video file opens and plays within a media player, as shown in Figure 35.6. Figure 35.6. Exported AVI file playing in a media player. [View full size image]

To export a project using the MOV format, follow these steps:

1.	Open the Maze.anme file from the Chapter 35 folder on the CD. This file is taken from an earlier tutorial and shows an arrow being animated moving through a maze.
2.	Select the File, Export Animation menu command (Ctrl/Cmd+E). In the Export Animation dialog box, select the Antialiased edges, Apply Shape Effects, Apply Layer Effects, and the Render at Half Dimensions options. Then choose the QuickTime Movie option from the Output Format dropdown list and click the OK button.
3.	In the File dialog box that opens, give the export file a name with the .MOV extension and choose a location; then click the Save button.
4.	In the Video Compression dialog box, select the Sorenson Video 3 option from the Compressor drop-down list. Set the Frames per Second to 24 and enable the Keyframe Every option with a value of 24. Then drag the Compression Quality slider to High and click the OK button.
5.	After the export process is completed, the video file opens and plays within the QuickTime player, as shown in Figure 35.7. Figure 35.7. Exported MOV file playing in the QuickTime player. [View full size image]