afGetFrameCount(3dm)                                      afGetFrameCount(3dm)


NAME
     afGetFrameCount, AFgetframecnt, afGetTrackBytes, afGetDataOffset - get
     the total sample frame count / data bytes / data offset for a specified
     audio track from an AFfilehandle structure

SYNOPSIS
     #include <dmedia/audiofile.h>

     AFframecount afGetFrameCount(AFfilehandle file, int track)

     AFfileoffset afGetTrackBytes(AFfilehandle file, int track)

     int afGetDataOffset(AFfilehandle file, int track)

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

     track   is an integer which identifies an audio track in file.

             Since all currently supported file formats contain exactly one
             audio track per file, the constant AF_DEFAULT_TRACK should always
             be used here.

RETURN VALUE
     afGetFrameCount() returns the total number of sample frames in track.
     afGetTrackBytes() returns the total number of bytes of audio data in
     track.  afGetDataOffset() returns the offset in bytes to the beginning of
     the audio data in track.

     In case of error, -1 is returned by all of these routines.

DESCRIPTION
     an audio track in the file represented by the AFfilehandle argument.

     In general, each sample frame in a given track consists of n samples,
     where n is the value returned by afGetChannels(3dm) for track.  For
     monaural data, a sample frame consists of a single audio sample.  For
     stereo data, a sample frame consists of a <left, right> stereo sample
     pair.

     afGetTrackBytes() returns the total number of bytes of raw audio data
     (i.e., prior to decompression) in track.  This is useful for determining
     raw file seek points, etc.

     The return types AFframecount and AFfileoffset are large enough to hold
     the maximum possible frame count value  and maximum possible byte size,
     respectively, for the current file system.


CAVEATS
     This routine may not function correctly if the user changes the file
     position on the file descriptor for the AFfilehandle being manipulated.
     See the section CAVEATS FOR USING THE HANDLE'S FILE DESCRIPTOR in
     afIntro(3dm) for some important information about how to deal with this
     situation.

SEE ALSO
     afOpenFile(3dm), afWriteFrames(3dm), afReadFrames(3dm),
     afGetChannels(3dm).  afGetVirtualChannels(3dm), afSetVirtualChannels(3dm)


                                                                        Page 2