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Move library tree where it belongs
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lib-src/libsamplerate/doc/api_simple.html
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lib-src/libsamplerate/doc/api_simple.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
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<HTML>
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<HEAD>
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<TITLE>
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Secret Rabbit Code (aka libsamplerate)
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</TITLE>
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<META NAME="Author" CONTENT="Erik de Castro Lopo (erikd AT mega-nerd DOT com)">
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<META NAME="Version" CONTENT="libsamplerate-0.1.7">
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<META NAME="Description" CONTENT="The Secret Rabbit Code Home Page">
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<META NAME="Keywords" CONTENT="libsamplerate sound resample audio dsp Linux">
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<LINK REL=StyleSheet HREF="SRC.css" TYPE="text/css" MEDIA="all">
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</HEAD>
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<BODY TEXT="#FFFFFF" BGCOLOR="#000000" LINK="#FB1465" VLINK="#FB1465" ALINK="#FB1465">
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<!-- pepper -->
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<CENTER>
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<IMG SRC="SRC.png" HEIGHT=100 WIDTH=760 ALT="SRC.png">
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</CENTER>
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<!-- pepper -->
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<BR>
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<!-- pepper -->
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<TABLE ALIGN="center" WIDTH="98%">
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<TR>
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<TD VALIGN="top">
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<BR>
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<DIV CLASS="nav">
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<BR>
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<A HREF="index.html">Home</A><BR>
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<BR>
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<A HREF="api_simple.html">Simple API</A><BR>
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<A HREF="api_full.html">Full API</A><BR>
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<A HREF="api_callback.html">Callback API</A><BR>
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<A HREF="api_misc.html">Miscellaneous</A><BR>
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<A HREF="api_misc.html#ErrorReporting">Error Handling</A><BR>
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<BR>
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<DIV CLASS="block">
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Author :<BR>Erik de Castro Lopo
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<BR><BR>
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<!-- pepper -->
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</DIV>
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<IMG SRC=
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"/cgi-bin/Count.cgi?ft=6|frgb=55;55;55|tr=0|md=6|dd=B|st=1|sh=1|df=src_api.dat"
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HEIGHT=30 WIDTH=100 ALT="counter.gif">
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</DIV>
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</TD>
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<!-- pepper -->
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<!-- ######################################################################## -->
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<!-- pepper -->
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<TD VALIGN="top">
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<DIV CLASS="block">
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<H1><B>Simple API</B></H1>
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<P>
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<B>Important Note:</B>
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The simple API is not designed to work on small chunks of a larger piece of
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audio.
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If you attempt to use it this way you are doing it wrong and will not get the
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results you want.
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For processing audio data in chunks you <b>must</b> use the
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<a href="api_full.html">full api</a>
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or the
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<a href="api_callback.html">callback based api</a>.
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</P>
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<br/><br/>
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<P>
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The simple API consists of a single function :
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</P>
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<PRE>
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int src_simple (SRC_DATA *data, int converter_type, int channels) ;
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</PRE>
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<P>
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The use of this function rather than the more fully featured API requires the caller
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to know the total length of the input data before hand and that all input and output
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data can be held in the system's memory at once.
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It also assumes that there is a single constant ratio between input and output sample
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rates.
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<!--
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If these conditions cannot be met, the full featured API should be used instead.
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In addition, this documentation is complemented by this
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<A HREF="ex_simple.html">example code</A>. -->
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</P>
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<P>
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Dealing with the easy stuff first, the <B>converter_type</B> parameter should be
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one of the values defined in <B>samplerate.h</B> and documented
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<A HREF="api_misc.html#Converters">here</A> while the <b>channels</b> parameter
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specifies the number of interleaved channels that the sample rate converter
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is being asked to process (number of input channels and output channels is always
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equal).
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There is no hard upper limit on the number of channels; it is limited purely
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by the amount of memory available.
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</P>
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<P>
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The first parameter to <B>src_simple</B> is a pointer to an <B>SRC_DATA</B> struct
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(more info <A HREF="api_misc.html#SRC_DATA">here</A>) defined as follows:
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</P>
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<PRE>
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typedef struct
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{ float *data_in, *data_out ;
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long input_frames, output_frames ;
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long input_frames_used, output_frames_gen ;
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int end_of_input ;
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double src_ratio ;
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} SRC_DATA ;
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</PRE>
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<P>
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The fields of this struct which must be filled in by the caller are:
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</P>
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<PRE>
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data_in : A pointer to the input data samples.
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input_frames : The number of frames of data pointed to by data_in.
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data_out : A pointer to the output data samples.
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output_frames : Maximum number of frames pointer to by data_out.
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src_ratio : Equal to output_sample_rate / input_sample_rate.
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</PRE>
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<P>
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When the <B>src_simple</B> function returns <B>output_frames_gen</B> will be
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set to the number of output frames generated and <B>input_frames_used</B> will
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be set to the number of input frames used to generate the provided number of
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output frames.
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</P>
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<P>
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The <B>src_simple</B> function returns a non-zero value when an error occurs.
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See <A HREF="api_misc.html#ErrorReporting">here</A> for how to convert the error value into
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a text string.
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</P>
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</DIV>
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</TD></TR>
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</TABLE>
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</BODY>
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</HTML>
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