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Compression Settings: Video for Windows

Use the Select Compressor dialog to choose a codec and its related settings for an AVI movie. The default codec is Microsoft Video 1.

Note: If you click Process to begin rendering before setting these options, combustion will prompt you to do so before continuing.

To set the Video for Windows compression settings:
  1. On the Output Settings panel, select Video for Windows from the Format list.
  2. Click Options.
  3. The Select Compressor dialog appears.

  4. Select a codec from the Compressor list. For information on the options available, see Choosing a Video for Windows Compressor.
  5. Adjust the following options, if required.


    Compression Quality

    Increase or decrease the quality of the compression.

    Key Frame Every

    Add a complete frame at the specified interval. Most codecs add keyframes when necessary, usually when the difference between frames is greater than 90%.

    Data Rate

    Create a movie that "maxes out" at the specified data rate per frame. Use this option (if the selected codec supports it) to create movies optimized for CD-ROM or web playback.


    Set any additional parameters for the selected codec. For example, click Configure for the Microsoft Video 1 codec to adjust the Temporal Quality Ratio using a slider.

  6. Click OK.

Choosing a Video for Windows Compressor

Several compressors are built into AVI, and each has its advantages and disadvantages. AVI movies have much the same playback speed and compression issues as QuickTime movies. Unfortunately, none of the built-in codecs for Video for Windows support alpha channels embedded in the movie. Therefore, if you need to output 32-bit files, you should probably use a sequence of images (such as TARGA) instead.

The following options are typically available when standard Video for Windows software is present. However, they may vary depending on your installation.


Uses a special compression algorithm that allows for fast decompression at the expense of relatively slow compression. As such, it is well suited for playback on the computer via a CD-ROM or other media. Cinepak is a lossy method regardless of the quality setting; however, you can usually get real-time playback with a wide variety of processor speeds with this codec.

Intel Video 5.4

Indeo Video Interactive (IVI) is a high-quality, wavelet-based codec. It provides good image quality.

Microsoft Video 1

Uses a compression algorithm optimized for fast decompression. However, this codec supports up to 16-bit color depth only, so it may not be suitable for most projects created with combustion.

Full Frames (Uncompressed)

Uses no compression on the AVI movie. This codec is typically used for storage of a movie that needs to be identical (that is, with lossless compression) to the original. Using this codec can generate very large files and take up quite a bit of hard drive space because of the total lack of compression.

Note: These are not the only codecs you might encounter. If you have installed a Video for Windows-compatible video card, or additional Video for Windows software, there may be additional codecs available to you. For more information about these, consult the manual of your particular video card or software.

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