Quick links to procedures on this page:
The AVI format supports several compression schemes. The following descriptions should help you choose one; however, you’ll probably want to experiment with different compressors and settings to identify the best settings for your work. You may also have different compression methods available.
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The Cinepak method produces acceptable motion and image quality at remarkably small file sizes. It is the preferred format for CD delivery and transfer across the Internet. Cinepak takes a long time to compress, and it can be difficult to find the best compression settings for certain image types and frame rates. |
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The Microsoft Video 1 method is designed for recording and playing back digitized video at high rates. |
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The Full Frames (Uncompressed) method uses no compression, so the images retain all of their quality. With a large frame size, some computers might not be fast enough to play at a high frame rate. This is the preferred format for transferring Corel Painter movies to AVI-editing applications. |
The compression ratio is inversely proportional to image quality. In the Video Compression dialog box, the Compression Quality slider allows you to set an optimum level between the amount of compression and image quality.
Key frames are used in temporal compression methods. Each key frame is stored in its entirety. The next set of frames, up to the next key, are saved only as changes. With some compression methods, you can specify the frequency of key frames with the Key Frame Every [Number] Frames option.
With some compression methods, you can also limit the speed of data transmission with the Data Rate option. The data rate limit overrides the Quality slider setting, if necessary, to keep the compressed movie within the set limit.
Understanding frame rate
Frame rate describes the number of image frames displayed per second (fps). The frame rate can determine not only how big a file your animation is, but also how smooth the motion appears.
When you save a movie as an AVI file, you can specify the rate of display. This doesn’t necessarily mean that what you specify is what you’ll experience. Factors like frame size, compression method, and computer speed can prevent some movies from achieving their set rate. If your animations will be viewed on the computer only, frame rates of 8, 10, and 12 fps are good choices. If your animations will be viewed elsewhere, you should consider the following frame rates:
These frame rates are sufficient to produce smooth, continuous motion with filmed or video-recorded subjects.
Animation drawings contain far less detail than live-action images. The difference in the level of detail allows animations to be produced at frame rates significantly lower than those designed for live action. Because of the smoothness of color fills and continuity between images, animations can look quite nice at rates between 10 and 15 fps.
You must consider frame rates to know how many drawings are needed to make actions smooth, natural, and consistent throughout the project.
The computer can display frames at any reasonable rate. The Frame Stacks panel provides control over frame display rates. You can preview an animation at a rate of 1 to 40 fps.
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In the Save Movie dialog box, enable the Save Movie As AVI option, and specify the number of frames per second. |
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In the Enter Movie Name dialog box, choose a location, enter a name for the file, and click Save. |
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In the Video Compression dialog box, choose a compression method from the Compressor list box. |
Save As.