afGetFrameCount(3dm)					  afGetFrameCount(3dm)

NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/audiofile.h>

     AFframecount afGetFrameCount(AFfilehandle file, int track)

     AFfileoffset afGetTrackBytes(AFfilehandle file, int track)

     int afGetDataOffset(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 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    [Toc]    [Back]

     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    [Toc]    [Back]

     afGetFrameCount(3dm) returns the current total number of sample frames in
     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.






									Page 1






afGetFrameCount(3dm)					  afGetFrameCount(3dm)

CAVEATS    [Toc]    [Back]

     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    [Toc]    [Back]

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


									PPPPaaaaggggeeee 2222