afGetChannels(3dm)                                          afGetChannels(3dm)


NAME
     afGetChannels, afGetVirtualChannels - get the number of interleaved track
     / virtual channels from an AFfilehandle structure for an audio track

SYNOPSIS
     #include <dmedia/audiofile.h>

     int afGetChannels(AFfilehandle file, int track)

     int afGetVirtualChannels(AFfilehandle file, int track)

PARAMETER
     file    is an AFfilehandle structure, previously created by a call to
             afOpenFile(3dm).

     track   is an integer which identifies the audio track in the file.
             Since all currently supported file formats allow at most one
             audio track per file, the constant value AF_DEFAULT_TRACK should
             always be used for this argument.

RETURN VALUE
     afGetChannels() and afGetVirtualChannels() return a nonnegative integer
     value if successful, or -1 on failure.

DESCRIPTION
     afGetChannels() returns the number of interleaved channels in the
     specified audio track in the file represented by the AFfilehandle
     argument.

     For example, the audio track in a stereo AIFF-C file contains 2
     interleaved channels.  The audio track in a mono AIFF-C file contains 1
     channel.

     afGetVirtualChannels() returns the number of virtual interleaved channels
     in the specified audio track represented by the AFfilehandle argument, as
     set by the most recent call to afSetVirtualChannels(3dm).  The default
     value is the number of channels in the track's underlying file.  See
     afIntro(3dm) for an explanation of virtual format.

CAVEATS
     afGetChannels() may return any number of channels, even for AIFF/AIFF-C
     files.  Be sure to check the number of channels of any file opened for
     reading and make sure your program can handle that number.  See
     afSetVirtualChannels(3dm) for a technique for dealing with files with
     unexpected numbers of channels in a simple and clean way.

SEE ALSO
     afOpenFile(3dm), afReadFrames(3dm), afInitChannels(3dm),
     afSetVirtualChannels(3dm)


                                                                        Page 1