Inside Macintosh: Sound /

Chapter 6 - Audio Components / Audio Components Reference

Data Structures

Audio Information Records

You return information about the capabilities of your audio component in the info parameter passed to your AudioGetInfo function. The info parameter contains a pointer to an audio information record. An audio information record is defined by the AudioInfo data type.

typedef struct {
   long           capabilitiesFlags;   /*device capabilities*/
   long           reserved;            /*reserved*/
   unsigned short numVolumeSteps;      /*number of volume steps*/
} AudioInfo, *AudioInfoPtr;

Field Description

capabilitiesFlags

A set of bit flags specifying the capabilities of the audio component. You can use constants to set some of these bits:

#define audioDoesMono                  (1L<<0)  /*supports mono output*/
#define audioDoesStereo                (1L<<1)  /*supports stereo output*/
#define audioDoesIndependentChannels   (1L<<2)  /*supports independent 
                                          software control of each channel*/

reserved

Reserved for use by Apple Computer, Inc.

numVolumeSteps

The number of volume steps your audio component supports.