afGetTrackIDs(3dm)afGetTrackIDs(3dm)NAME
afGetTrackIDs - get the list of track descriptor id's for the given
AFfilehandle
SYNOPSIS
#include <dmedia/audiofile.h>
int afGetTrackIDs(AFfilehandle file, int trackids[])
PARAMETER
file expects an AFfilehandle structure, created when an audio file
was opened by a call to afOpenFile().
trackids expects an array of integer locations used to return a list of
(unique) positive track id's which can be used to reference
the audio tracks in a file.
If trackids is a null pointer, afGetTrackIDs() will simply
return the number of tracks in the file. This value can be
used to allocate a trackids array, which can in turn be passed
back to afGetTrackIDs().
RETURN VALUEafGetTrackIDs() returns a nonnegative integer count of the number of
audio tracks in the file, or -1 in case of error.
DESCRIPTION
You can call afGetTrackIDs()) with a null trackids pointer to obtain the
number of audio tracks contained in file.
You can use this count to allocate a trackids[] buffer, which you pass
back to afGetTrackIDs to obtain a list of unique track id's. You can then
use these id's to reference the various tracks in the file.
For the current release of the Audio File Library, this routine is a
placeholder, since all currently supported file formats always contain
one track which should be referenced using the constant ID
AF_DEFAULT_TRACK.
CAVEATS
This function may return more than one track. Future releases of the
Audio File Library may support formats which contain multiple tracks. An
application might want to reject such a file, or perhaps use the first
track. The library does define the correct behavior.
SEE ALSOafOpenFile(3dm), afReadFrames(3dm), afWriteFrames(3dm),
afInitTrackIDs(3dm)
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