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'\" t
.\" Title: afGetFrameSize
.\" Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.75.2 <http://docbook.sf.net/>
.\" Date: 04/30/2012
.\" Manual: \ \&
.\" Source: Audio File Library 0.3.4
.\" Language: English
.\"
.TH "AFGETFRAMESIZE" "3" "04/30/2012" "Audio File Library 0\&.3\&.4" "\ \&"
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.SH "NAME"
afGetFrameSize \- calculate the frame size in bytes for an audio track
.SH "SYNOPSIS"
.sp
.nf
#include <audiofile\&.h>
.fi
.sp
.nf
float afGetFrameSize (AFfilehandle file, int track, int expand3to4);
.fi
.SH "PARAMETERS"
.sp
\fIfile\fR is a valid AFfilehandle\&.
.sp
\fItrack\fR is an integer which refers to a specific audio track in the file\&. At present no supported audio file format allows for more than one audio track within a file, so track should always be AF_DEFAULT_TRACK\&.
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\fIexpand3to4\fR is a boolean\-valued integer indicating whether frame size calculation will treat 24\-bit data as having a size of 3 bytes or 4 bytes\&.
.SH "DESCRIPTION"
.sp
afGetFrameSize returns the number of bytes in a frame in a given audio track\&.
.sp
A sample frame consists of one or more samples\&. For a monaural track, a sample frame will always contain one sample\&. For a stereophonic track, a sample frame will always contain two samples, one for the left channel and one for the right channel\&.
.sp
A non\-zero value of \fIexpand3to4\fR should be used when calculating the frame size for storage in memory (since 24\-bit audio data is presented in memory as a 4\-byte sign\-extended integer), while a value of zero should be used for calculating storage on disk where no padding is added\&. The parameter \fIexpand3to4\fR is ignored unless the specified audio track contains 24\-bit audio data\&.
.SH "AUTHOR"
.sp
Michael Pruett <michael@68k\&.org>
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