\hypertarget{a00906}{}\doxysection{Sidechain Inputs}
\label{a00906}\index{Sidechain Inputs@{Sidechain Inputs}}
Routing custom audio streams to a plug-\/in. 

\hypertarget{a00906_additionalFeatures_Sidechain_overview}{}\doxysubsection{Overview of Sidechain Inputs}\label{a00906_additionalFeatures_Sidechain_overview}
If applicable, plug-\/ins may choose to enable sidechain inputs. If a sidechain is enabled, a menu is added to the plug-\/in\textquotesingle{}s header that allows the user to choose an interface or bus as the sidechain, or \char`\"{}key input\char`\"{}. Once enabled, the plug-\/in will be able to access sidechain input just like any other input signal. Currently, DAE is limited to mono sidechain inputs.\hypertarget{a00906_additionalFeatures_Sidechain_adding}{}\doxysubsection{Adding a Sidechain Input to an Effect}\label{a00906_additionalFeatures_Sidechain_adding}
Setting up a sidechain input is fairly straight forward. You will want to add a physical address within your context structure, and then \char`\"{}describe\char`\"{} the sidechain in Describe.

Context Structure\+:


\begin{DoxyCode}{0}
\DoxyCodeLine{\textcolor{comment}{//=============================}}
\DoxyCodeLine{\textcolor{comment}{//\ Component\ context\ definitions}}
\DoxyCodeLine{\textcolor{comment}{//=============================}}
\DoxyCodeLine{}
\DoxyCodeLine{\textcolor{comment}{//\ Context\ structure}}
\DoxyCodeLine{\textcolor{keyword}{struct\ }SMyPlugIn\_Alg\_Context}
\DoxyCodeLine{\{}
\DoxyCodeLine{\ \ \ [...]}
\DoxyCodeLine{\ \ \ int32\_t\ \ *\ mSideChainP;}
\DoxyCodeLine{\ \ \ [...]}
\DoxyCodeLine{\};}
\DoxyCodeLine{}
\DoxyCodeLine{\textcolor{comment}{//\ Physical\ addresses\ within\ the\ context}}
\DoxyCodeLine{\textcolor{keyword}{enum}\ EDemoDist\_Alg\_PortID}
\DoxyCodeLine{\{}
\DoxyCodeLine{\ \ \ \ [...]}
\DoxyCodeLine{\ \ \ \ ,MyPlugIn\_AlgFieldID\_SideChain\ \ =\ \mbox{\hyperlink{a00542_acf807247ecd6e5899dc9dc31644e9a1d}{AAX\_FIELD\_INDEX}}\ (SDemoDist\_Alg\_Context,\ mSideChainP)}
\DoxyCodeLine{\ \ \ \ [...]}
\DoxyCodeLine{\};}

\end{DoxyCode}


Describe\+: 
\begin{DoxyCode}{0}
\DoxyCodeLine{\textcolor{comment}{//\ ***************************************************************************}}
\DoxyCodeLine{\textcolor{comment}{//\ ROUTINE:\ DescribeAlgorithmComponent}}
\DoxyCodeLine{\textcolor{comment}{//\ Algorithm\ component\ description}}
\DoxyCodeLine{\textcolor{comment}{//\ ***************************************************************************}}
\DoxyCodeLine{\textcolor{keyword}{static}\ \textcolor{keywordtype}{void}\ DescribeAlgorithmComponent(\ \mbox{\hyperlink{a02214}{AAX\_IComponentDescriptor}}\ *\ outDesc\ )}
\DoxyCodeLine{\{}
\DoxyCodeLine{\ \ \ \ \mbox{\hyperlink{a00542_a4d8f69a697df7f70c3a8e9b8ee130d2f}{AAX\_Result}}\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ err\ =\ \mbox{\hyperlink{a00539_a5f8c7439f3a706c4f8315a9609811937aeddbd1bb67e3a66e6af54a4b4a7a57b3}{AAX\_SUCCESS}};}
\DoxyCodeLine{}
\DoxyCodeLine{\ \ \ \ [...]}
\DoxyCodeLine{\ \ \ \ err\ =\ outDesc.\mbox{\hyperlink{a02214_a1e0c9508d1eb0c9a60a87a0fb69f1dbe}{AddSideChainIn}}(eDemoDist\_AlgFieldID\_SideChain);}
\DoxyCodeLine{\ \ \ \ [...]}
\DoxyCodeLine{\ \ \ \ properties-\/>AddProperty\ (\ \mbox{\hyperlink{a00608_a13e384f22825afd3db6d68395b79ce0da3399fcd8ff459de1e3de0c98d40a5094}{AAX\_eProperty\_SupportsSideChainInput}},\ \textcolor{keyword}{true}\ );}
\DoxyCodeLine{\ \ \ \ [...]}
\DoxyCodeLine{\}}

\end{DoxyCode}


\begin{DoxyRefDesc}{Todo}
\item[\mbox{\hyperlink{a00878__todo000001}{Todo}}]Is properties-\/\texorpdfstring{$>$}{>}Add\+Property ( AAX\+\_\+e\+Property\+\_\+\+Supports\+Side\+Chain\+Input, true ) even necessary?!?! I believe I saw a p.\+i. that does not declare this...\end{DoxyRefDesc}


In order to tell whether there is sidechain information available to your plug-\/in, check for a null pointer within your algorithm\textquotesingle{}s process function. The sidechain channel will show up as an additional stem from the original stem format you declare. That is to stay, for a stereo plug-\/in, the sidechain channel will be the third channel passed in.


\begin{DoxyCode}{0}
\DoxyCodeLine{\textcolor{comment}{//==============================================================================}}
\DoxyCodeLine{\textcolor{comment}{//\ Processing\ function\ definition}}
\DoxyCodeLine{\textcolor{comment}{//==============================================================================}}
\DoxyCodeLine{}
\DoxyCodeLine{\textcolor{keywordtype}{void}}
\DoxyCodeLine{\mbox{\hyperlink{a00542_aaa22112139aa627574b1ef562f579d43}{AAX\_CALLBACK}}}
\DoxyCodeLine{MyPlugIn\_AlgorithmProcessFunction\ (}
\DoxyCodeLine{\ \ \ \ SMyPlugIn\_Alg\_Context\ *\ \textcolor{keyword}{const}\ \ \ inInstancesBegin\ [],}
\DoxyCodeLine{\ \ \ \ \textcolor{keyword}{const}\ \textcolor{keywordtype}{void}\ *\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ inInstancesEnd)}
\DoxyCodeLine{\{}
\DoxyCodeLine{\ \ \ \ [...]}
\DoxyCodeLine{\ \ \ \ int32\_t\ sideChainChannel\ =\ *instance-\/>mSideChainP;\ \ \ }
\DoxyCodeLine{\ \ \ \ \textcolor{keywordtype}{float}\ *\ AAX\_RESTRICT\ sideChainInput\ =\ 0;}
\DoxyCodeLine{\ \ \ \ \textcolor{keywordflow}{if}\ (\ sideChainChannel\ )}
\DoxyCodeLine{\ \ \ \ \ \ sideChainInput\ =\ instance-\/>mInputPP\ [sideChain]Channel;}
\DoxyCodeLine{\ \ \ \ [...]}
\DoxyCodeLine{\}}

\end{DoxyCode}
 Collaboration diagram for Sidechain Inputs\+:
% FIG 0
