diff --git a/src/drivers/Qt/AviRiffViewer.cpp b/src/drivers/Qt/AviRiffViewer.cpp
index a30aab9d..b646bcf0 100644
--- a/src/drivers/Qt/AviRiffViewer.cpp
+++ b/src/drivers/Qt/AviRiffViewer.cpp
@@ -62,6 +62,8 @@ AviRiffViewerDialog::AviRiffViewerDialog(QWidget *parent)
 
 	avi = NULL;
 	lastChunk = NULL;
+	riffSize = 0;
+	progressDialog = NULL;
 	memset( strhType, 0, sizeof(strhType) );
 
 	setWindowTitle("AVI RIFF Viewer");
@@ -274,6 +276,8 @@ void AviRiffViewerDialog::openAviFileDialog(void)
 //----------------------------------------------------------------------------
 int AviRiffViewerDialog::openFile( const char *filepath )
 {
+	int ret;
+
 	if ( avi )
 	{
 		closeFile();
@@ -286,12 +290,31 @@ int AviRiffViewerDialog::openFile( const char *filepath )
 		return -1;
 	}
 
+	progressDialog = new QProgressDialog( tr("Loading AVI File"), tr("Cancel"), 0, 1000, this );
+	progressDialog->setWindowModality(Qt::WindowModal);
+
 	itemStack.clear();
 	lastChunk = NULL;
 	memset( strhType, 0, sizeof(strhType) );
 
+	riffSize = 0;
 	avi->setRiffWalkCallback( ::riffWalkCallback, this );
-	avi->riffwalk();
+	ret = avi->riffwalk();
+
+	if ( ret )
+	{
+		if ( progressDialog->wasCanceled() )
+		{
+			QMessageBox::information( this, tr("AVI Load Canceled"), tr("AVI Load Canceled By User.") );
+		}
+		else
+		{
+			progressDialog->reset();
+			QMessageBox::critical( this, tr("AVI Load Error"), tr("AVI format errors detected. Unable to load file.") );
+		}
+		closeFile();
+	}
+	delete progressDialog; progressDialog = NULL;
 
 	return 0;
 }
@@ -310,12 +333,33 @@ int AviRiffViewerDialog::riffWalkCallback( int type, long long int fpos, const c
 {
 	AviRiffTreeItem *item, *groupItem;
 
+	if ( riffSize > 0 )
+	{
+		int prog;
+
+		prog = (1000llu * fpos) / riffSize;
+
+		if ( prog > 1000 )
+		{
+			prog = 1000;
+		}
+		if ( progressDialog )
+		{
+			if (progressDialog->wasCanceled())
+			{
+				return -1;
+			}
+			progressDialog->setValue( prog );
+		}
+	}
 	switch ( type )
 	{
 		case gwavi_t::RIFF_START:
 		{
 			item = new AviRiffTreeItem(type, fpos, fourcc, size);
 
+			riffSize = size;
+
 			itemStack.push_back(item);
 
 			riffTree->addTopLevelItem(item);
diff --git a/src/drivers/Qt/AviRiffViewer.h b/src/drivers/Qt/AviRiffViewer.h
index 69669f40..7d62070d 100644
--- a/src/drivers/Qt/AviRiffViewer.h
+++ b/src/drivers/Qt/AviRiffViewer.h
@@ -21,6 +21,7 @@
 #include <QTreeView>
 #include <QTreeWidget>
 #include <QTreeWidgetItem>
+#include <QProgressDialog>
 #include <QTabWidget>
 #include <QMenuBar>
 #include <QAction>
@@ -80,8 +81,10 @@ protected:
 	AviRiffTreeItem *lastChunk;
 	std::list <AviRiffTreeItem*> itemStack;
 	char strhType[8];
+	size_t       riffSize;
 
 	QTabWidget *tabs;
+	QProgressDialog *progressDialog;
 
 private:
 public slots:
diff --git a/src/drivers/Qt/avi/gwavi.cpp b/src/drivers/Qt/avi/gwavi.cpp
index ab6aec17..235b9e54 100644
--- a/src/drivers/Qt/avi/gwavi.cpp
+++ b/src/drivers/Qt/avi/gwavi.cpp
@@ -673,6 +673,11 @@ int gwavi_t::riffwalk(void)
 		return -1;
 
 	fourcc[4] = 0;
+
+	if ( strcmp( fourcc, "RIFF") != 0 )
+	{
+		return -1;
+	}
 	//printf("RIFF Begin: '%s'\n", fourcc );
 
 	if (read_uint(in, fileSize) == -1)
@@ -692,7 +697,10 @@ int gwavi_t::riffwalk(void)
 
 	if ( riffWalkCallback )
 	{
-		riffWalkCallback( RIFF_START, fpos, fourcc, fileSize, riffWalkUserData );
+		if ( riffWalkCallback( RIFF_START, fpos, fourcc, fileSize, riffWalkUserData ) )
+		{
+			return -1;
+		}
 	}
 
 	while ( size >= 4 )
@@ -731,7 +739,10 @@ int gwavi_t::riffwalk(void)
 
 	if ( riffWalkCallback )
 	{
-		riffWalkCallback( RIFF_END, fpos, fourcc, fileSize, riffWalkUserData );
+		if ( riffWalkCallback( RIFF_END, fpos, fourcc, fileSize, riffWalkUserData ) )
+		{
+			return -1;
+		}
 	}
 	return 0;
 }
@@ -830,7 +841,10 @@ unsigned int gwavi_t::readList(int lvl)
 	{
 		fpos = ftell(in);
 
-		riffWalkCallback( LIST_END, fpos, listType, listSize, riffWalkUserData );
+		if ( riffWalkCallback( LIST_END, fpos, listType, listSize, riffWalkUserData ) )
+		{
+			return 0;
+		}
 	}
 	return bytesRead+4;
 }
@@ -856,7 +870,10 @@ unsigned int gwavi_t::readChunk(const char *id, int lvl)
 
 	if ( riffWalkCallback )
 	{
-		riffWalkCallback( CHUNK_START, fpos-4, id, chunkSize, riffWalkUserData );
+		if ( riffWalkCallback( CHUNK_START, fpos-4, id, chunkSize, riffWalkUserData ) )
+		{
+			return 0;
+		}
 	}
 
 	if ( chunkSize == 0 )