Added FilterGraph

Clement Champetier · Clement Champetier · commit 4b7dc836d272 · 2015-11-20T19:07:28.000+01:00
The class handles a list of filters.
diff --git a/src/AvTranscoder/filter/FilterGraph.cpp b/src/AvTranscoder/filter/FilterGraph.cpp
@@ -0,0 +1,71 @@
+#include "FilterGraph.hpp"
+
+extern "C" {
+#include <libavfilter/avfilter.h>
+}
+
+#include <stdexcept>
+
+
+namespace avtranscoder
+{
+
+FilterGraph::FilterGraph()
+	: _graph( avfilter_graph_alloc() )
+	, _filters()
+{
+	if( ! _graph )
+		throw std::runtime_error( "Unable to create filter graph: out of memory.");
+}
+
+FilterGraph::~FilterGraph()
+{
+	for( std::vector< Filter >::iterator it = _filters.begin(); it < _filters.end(); ++it )
+	{
+		avfilter_free( it->second );
+	}
+	avfilter_graph_free( &_graph );
+}
+
+void FilterGraph::addFilter( const std::string& filtername )
+{
+	AVFilter* filter = avfilter_get_by_name( filtername.c_str() );
+	if( filter )
+	{
+		AVFilterContext* context = NULL;
+		const int err = avfilter_graph_create_filter( &context, filter, NULL, filtername.c_str(), NULL, _graph );
+		if( err < 0 )
+		{
+			std::string msg( "Cannot add filter " );
+			msg += filtername;
+			msg += " to the graph: ";
+			msg += getDescriptionFromErrorCode(err);
+			throw std::runtime_error( msg );
+		}
+		else
+			_filters.push_back( std::make_pair(filter, context) );
+	}
+	else
+	{
+		throw std::runtime_error( "Cannot find filter " + filtername );
+	}
+}
+
+void FilterGraph::connectFilters()
+{
+	// connecting filters
+	for( size_t index = 0; index < _filters.size()+1; index+=2 )
+	{
+		const int err = avfilter_link( _filters.at(index).second, 0, _filters.at(index+1).second, 0);
+		if( err < 0 )
+		{
+			throw std::runtime_error( "Error connecting filters." );
+		}
+	}
+	// configuring
+	const int err = avfilter_graph_config( _graph, NULL );
+	if( err < 0 )
+		throw std::runtime_error( "Error configuring the filter graph.");
+}
+
+}
diff --git a/src/AvTranscoder/filter/FilterGraph.hpp b/src/AvTranscoder/filter/FilterGraph.hpp
@@ -0,0 +1,47 @@
+#ifndef _AV_TRANSCODER_FILTER_FILTER_GRAPH_HPP_
+#define _AV_TRANSCODER_FILTER_FILTER_GRAPH_HPP_
+
+#include <AvTranscoder/common.hpp>
+
+#include <vector>
+#include <utility>
+
+struct AVFilterGraph;
+struct AVFilter;
+struct AVFilterContext;
+
+namespace avtranscoder
+{
+
+/**
+ * @brief 
+ **/
+class AvExport FilterGraph
+{
+private:
+	FilterGraph( const FilterGraph& otherFilterGraph );
+	FilterGraph& operator=( const FilterGraph& otherFilterGraph );
+
+public:
+	typedef std::pair<AVFilter*, AVFilterContext*> Filter;
+
+public:
+	FilterGraph();
+	~FilterGraph();
+
+	void addFilter( const std::string& filtername );
+	Filter& getFirstFilter() { return _filters.at(0); }
+	Filter& getLastFilter() { return _filters.at(_filters.size()-1); }
+
+	bool hasFilters() const { return ! _filters.empty(); }
+
+	void connectFilters();
+
+private:
+	AVFilterGraph* _graph;
+	std::vector< Filter > _filters;
+};
+
+}
+
+#endif
