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Inside Macintosh: QuickTime /

Chapter 3 - Image Compression Manager

This chapter describes the Image Compression Manager. The Image Compression Manager provides image-compression and image-decompression services to applications and other managers. If you are developing an application that works
with images, you should read this chapter to familiarize yourself with the features of the Image Compression Manager. If you want to develop a compressor or decompressor for use on the Macintosh computer, see Inside Macintosh: QuickTime Components for information about the software interfaces that your component must support in order to work with the Image Compression Manager.

Image compression benefits you by decreasing the amount of storage required for image data, decreasing the time required to exchange image data across networks, and decreasing the time required to read data from disks and CD-ROM volumes.

This chapter is divided into the following major sections:

Chapter Contents
Introduction to the Image Compression Manager
Data That Is Suitable for Compression
Storing Images
About Image Compression
Image-Compression Characteristics
Compression Ratio
Compression Speed
Image Quality
Compressors Supplied by Apple
The Photo Compressor
The Video Compressor
The Compact Video Compressor
The Animation Compressor
The Graphics Compressor
The Raw Compressor
Types of Images Suitable for Different Compressors
Using the Image Compression Manager
Getting Information About Compressors and Compressed Data
Working With Pictures
Compressing Images
Decompressing Images
Compressing Sequences
Decompressing Sequences
Decompressing Still Images From a Sequence
Using Screen Buffers and Image Buffers
A Sample Program for Compressing and Decompressing a Sequence of Images
A Sample Function for Saving a Sequence of Images to a Disk File
A Sample Function for Creating, Compressing, and Drawing a Sequence of Images
A Sample Function for Decompressing and Playing Back a Sequence From a Disk File
Spooling Compressed Data
Banding and Extending Images
Defining Key Frame Rates
Fast Dithering
Understanding Compressor Components
Image Compression Manager Reference
Data Types
The Image Description Structure
The Compressor Information Structure
The Compressor Name Structure
The Compressor Name List Structure
Compression Quality Constants
Image Compression Manager Function Control Flags
Image Compression Manager Functions
Getting Information About Compressor Components
Getting Information About Compressed Data
Working With Images
Working With Pictures and PICT Files
Making Thumbnail Pictures
Working With Sequences
Changing Sequence-Compression Parameters
Constraining Compressed Data
Changing Sequence-Decompression Parameters
Working With the StdPix Function
Aligning Windows
Working With Graphics Devices and Graphics Worlds
Application-Defined Functions
Data-Loading Functions
Data-Unloading Functions
Progress Functions
Completion Functions
Alignment Functions
Summary of the Image Compression Manager
C Summary
Data Types
Image Compression Manager Functions
Application-Defined Functions
Pascal Summary
Data Types
Image Compression Manager Routines
Application-Defined Routines
Result Codes

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© Apple Computer, Inc.
6 JUL 1996