Inside Macintosh: Sound

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;

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.