afSetTrackPCMMapping(3dm)			     afSetTrackPCMMapping(3dm)

NAME    [Toc]    [Back]

     afSetTrackPCMMapping - override the current PCM mapping values associated
     with a given track	in an AFfilehandle

SYNOPSIS    [Toc]    [Back]

     #include <dmedia/audiofile.h>

     int afSetTrackPCMMapping(AFfilehandle file, int track,
				 double	slope, double intercept,
				 double	minclip, double	maxclip)

PARAMETER    [Toc]    [Back]

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

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

		 Since all currently supported file formats contain only one
		 audio track, the value	AF_DEFAULT_TRACK should	always be used
		 here for now.

     slope	 is a double precision floating	point value which specifies an
		 amplitude scaling factor for the waveform to be associated
		 with track.

     intercept	 is a double precision floating	point value indicating the
		 audio waveform	vertical midpoint ( zero-crossing) value for
		 the audio data	associated with	track

     minclip	 is a double precision floating	point value indicating the
		 minimum or most negative audio	data sample value to be	read.
		 Any value less	than this will be set to minclip

     maxclip	 is a double precision floating	point value indicating the
		 maximum or most positive audio	data sample value to be	read.
		 Any value greater than	this will be set to maxclip

DESCRIPTION    [Toc]    [Back]

     afSetTrackPCMMapping() allows an application to override the default PCM
     mapping values associated with a track.  This causes the Audio File
     Library to	reinterpret the	sample data loaded by afReadFrames(3dm)
     according the the new mapping.

CAVEATS    [Toc]    [Back]

     PCM mapping is only useful	for modifying frames as	they are read into or
     written out from a	buffer via afReadFramesintercept will be 0.0 and minclip and maxclip will be negative



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afSetTrackPCMMapping(3dm)			     afSetTrackPCMMapping(3dm)



     and positive N, where N is	some non-zero positive value.

SEE ALSO    [Toc]    [Back]

     afInitPCMMapping(3dm), afSetVirtualPCMMapping(3dm),
     afGetVirtualPCMMapping(3dm), afReadFrames(3dm)


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