Inside Macintosh: Sound /

Chapter 5 - Sound Components / Sound Components Reference

Data Structures

Compression Information Records

When the Sound Manager calls your SoundComponentGetInfo routine with the siCompressionFactor selector, you need to return a pointer to a compression information record, which is defined by the CompressionInfo data type.

typedef struct {
   long           recordSize;
   OSType         format;
   short          compressionID;
   short          samplesPerPacket;
   short          bytesPerPacket;
   short          bytesPerFrame;
   short          bytesPerSample;
   short          futureUse1;
} CompressionInfo, *CompressionInfoPtr, **CompressionInfoHandle;

Field Description

recordSize

The size of this compression information record.

format

The compression format.

compressionID

The compression ID.

samplesPerPacket

The number of samples in each packet.

bytesPerPacket

The number of bytes in each packet.

bytesPerFrame

The number of bytes in each frame.

bytesPerSample

The number of bytes in each sample.

futureUse1

Reserved for use by Apple Computer, Inc. You should set this field to 0.