APPENDIX B
352
Compressing Video and Audio
Bit depth
The bit depth determines the number of colors that will be used to export the movie.
Higher bit depths create larger files. When you specify lower bit depths, you may be able to
retain some control over color quality by specifying a custom color palette (see “Video settings”
on page 61 and “Exporting video files” on page 304). If the option is not available, you’ve
chosen a codec that doesn’t support custom palettes or 8-bit color.
Frame size
For best picture quality, the frame size of the project should match the frame size
of the final video file. Where file size or data rate are more important than picture quality,
such as for Internet delivery, reducing the frame size may help compression by reducing the
initial amount of data to compress. For information about setting the frame size, see “Video
settings” on page 61 and “About output settings” on page 297.
Frame rate
For best motion quality, the frame rate of the project should match the frame
rate of the final video file. Where file size or data rate are more important than the quality
of motion, such as for Internet delivery, specifying a lower frame rate may help compression
by reducing the amount of data to compress. For information about setting the frame rate,
see “Video settings” on page 61 and “About output settings” on page 297.
Finding an appropriate codec
When editing, the Editing Mode you select in the Project Settings dialog box determines the
codecs available to you. When exporting, available codecs are determined by the File Type you
select in the Export Movie Settings dialog box. You can evaluate codecs by their intended uses,
compression methods, and how they handle different kinds of pictures or sound. Video for
Windows and QuickTime software are used for a wide range of video-related tasks, such as
videoconferencing, so they include many codecs which are not appropriate for video editing.
Codecs intended for purposes other than video editing are identified in this section so that you
can avoid them. If your video card provides hardware compression and its software is properly
installed, its codec will appear in the Compressor menu in the Video Settings panel of the
Project Settings dialog box. You can also access the codec in the dialog box for your video-
capture hardware, which you can open by clicking the Video button in the Capture Settings
panel of the Project Settings dialog box. See “Preparing for video capture” on page 93 and
“Setting up a video codec” on page 298.
c00.book for PS Page 352 Tuesday, March 31, 1998 1:28 PM
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