afGetChannels(3dm)					    afGetChannels(3dm)

NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/audiofile.h>

     int afGetChannels(AFfilehandle file, int track)

     int afGetVirtualChannels(AFfilehandle file, int track)

PARAMETER    [Toc]    [Back]

     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    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

     afOpenFile(3dm), afReadFrames(3dm), afInitChannels(3dm),
     afSetVirtualChannels(3dm)
afGetChannels(3dm)					    afGetChannels(3dm)

NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/audiofile.h>

     int afGetChannels(AFfilehandle file, int track)

     int afGetVirtualChannels(AFfilehandle file, int track)

PARAMETER    [Toc]    [Back]

     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    [Toc]    [Back]

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

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]

     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    [Toc]    [Back]

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


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