[libvidcap-commit] SF.net SVN: libvidcap: [34] trunk/examples/vidcapTester/GrabberManager.cpp

[libvidcap c. m. <lib...@li...>]

Revision: 34
          http://libvidcap.svn.sourceforge.net/libvidcap/?rev=34&view=rev
Author:   bcholew
Date:     2007-09-28 10:44:03 -0700 (Fri, 28 Sep 2007)

Log Message:
-----------
Have window render frames in the callback thread - so they won't back-up due to a blocked main thread.

Modified Paths:
--------------
    trunk/examples/vidcapTester/GrabberManager.cpp

Modified: trunk/examples/vidcapTester/GrabberManager.cpp
===================================================================
--- trunk/examples/vidcapTester/GrabberManager.cpp	2007-09-26 15:55:16 UTC (rev 33)
+++ trunk/examples/vidcapTester/GrabberManager.cpp	2007-09-28 17:44:03 UTC (rev 34)
@@ -1,345 +1,346 @@
-#include <stdexcept>
-
-#include <QApplication>
-#include <QDebug>
-#include <QIcon>
-#include <QMutexLocker>
-
-#include "GrabberManager.h"
-
-GrabberManager::GrabberManager(QObject * parent, const QString & title,
-		int width, int height, int framerate)
-	: QObject(parent),
-	  title_(title),
-	  width_(width),
-	  height_(height),
-	  framerate_(framerate),
-	  vc_(vidcap_initialize()),
-	  sapi_(0),
-	  ctxList_(0),
-	  srcList_(0),
-	  srcListLen_(0)
-{
-	qDebug() << "Starting grabber for each capture device...";
-
-	if ( !vc_ )
-		throw std::runtime_error("failed vidcap_initialize()");
-
-	if ( !(sapi_ = vidcap_sapi_acquire(vc_, 0)) )
-		throw std::runtime_error("failed to acquire default sapi");
-
-	if ( vidcap_sapi_info_get(sapi_, &sapiInfo_) )
-		throw std::runtime_error("failed to get default sapi info");
-
-	qDebug() << "sapi:" << sapiInfo_.identifier
-		<< "|" << sapiInfo_.description;
-
-	if ( vidcap_srcs_notify(sapi_, &GrabberManager::userNotificationCallback, this) )
-		throw std::runtime_error("failed vidcap_srcs_notify()");
-
-	srcListLen_ = vidcap_src_list_update(sapi_);
-
-	if ( srcListLen_ < 0 )
-		throw std::runtime_error("failed vidcap_src_list_update()");
-
-	srcList_ = new vidcap_src_info[srcListLen_];
-
-	if ( vidcap_src_list_get(sapi_, srcListLen_, srcList_) )
-		throw std::runtime_error("failed vidcap_srcList_get()");
-
-	ctxList_ = new mySourceContext[srcListLen_];
-
-	// Rescan on notification
-	// NOTE: connecting before mgr construction is complete
-	connect(this, SIGNAL(deviceNotification()),
-			this, SLOT(rescanDevices()));
-
-	// create a grabber for each video capture device
-	for ( int i = 0; i < srcListLen_; ++i )
-	{
-		qDebug() << "src:" << srcList_[i].identifier
-			<< "|" << srcList_[i].description;
-
-		createContext(&ctxList_[i], &srcList_[i]);
-	}
-}
-
-GrabberManager::~GrabberManager()
-{
-	qDebug() << "Destroying all grabbers...";
-
-	{
-		QMutexLocker locker(&sourceMutex_);
-
-		for ( int i = srcListLen_ - 1; i >= 0; --i )
-		{
-			if ( ctxList_[i].grabber )
-				delete ctxList_[i].grabber;
-
-			if ( ctxList_[i].window )
-				delete ctxList_[i].window;
-		}
-
-		delete [] ctxList_;
-		delete [] srcList_;
-	}
-
-	if ( vidcap_sapi_release(sapi_) )
-		qWarning() << "failed vidcap_sapi_release()";
-
-	vidcap_destroy(vc_);
-}
-
-void
-GrabberManager::killGrabber(Grabber *grabber)
-{
-	//  protect context list and srcListLen_ from concurrent access
-	//       (from notification callback)
-	QMutexLocker locker(&sourceMutex_);
-
-	for ( int i = 0; i < srcListLen_; ++i )
-	{
-		if ( ctxList_[i].grabber == grabber )
-		{
-			if ( ctxList_[i].grabber )
-				delete ctxList_[i].grabber;
-			ctxList_[i].grabber = 0;
-
-			if ( ctxList_[i].window )
-				delete ctxList_[i].window;
-			ctxList_[i].window = 0;
-			break;
-		}
-	}
-}
-
-void
-GrabberManager::shutdown()
-{
-	qDebug() << "grabber manager got signal to shutdown";
-
-	// cause message loop to exit
-	QApplication::quit();
-}
-
-int
-GrabberManager::userNotificationCallback(vidcap_sapi *, void * user_context)
-{
-	GrabberManager *grabMgr = (GrabberManager *)user_context;
-
-	// trigger main thread to handle this - rescan the devices
-	emit grabMgr->deviceNotification();
-
-	return 0;
-}
-
-void
-GrabberManager::rescanDevices()
-{
-	vidcap_src_info * newSrcList;
-	int newSrcListLen;
-
-	// query for device list
-	try
-	{
-		getFreshSrcList(newSrcList, newSrcListLen);
-	}
-	catch (std::runtime_error &e)
-	{
-		qCritical() << "exception while rescanning devices:" << e.what();
-		return;
-	}
-
-	bool removal = false;
-	bool addition = false;
-	// compare each existing device to new list
-	//    If it's not there, clean it up
-	for ( int oldIdx = 0; oldIdx < srcListLen_; ++oldIdx )
-	{
-		bool found = false;
-		for ( int newIdx = 0; newIdx < newSrcListLen; ++newIdx )
-		{
-			if ( !strcmp(srcList_[oldIdx].identifier,
-				newSrcList[newIdx].identifier) )
-			{
-				found = true;
-				break;
-			}
-		}
-
-		if ( !found )
-		{
-			removal = true;
-			qDebug() << "source removed:"
-				<< srcList_[oldIdx].description;
-
-			// NOTE: Source might not be capturing when
-			// removed, so don't rely on capture callback
-			// to clean up after a device removal.
-			//
-			// cleanup after this device removal
-			killGrabber(ctxList_[oldIdx].grabber);
-		}
-	}
-
-	mySourceContext * newCtxList = new mySourceContext[newSrcListLen];
-
-	// Compare each device in new list to old list
-	// If it's new, add it to the new context list
-	for ( int newIdx = 0; newIdx < newSrcListLen; ++newIdx )
-	{
-		bool found = false;
-		for ( int oldIdx = 0; oldIdx < srcListLen_; ++oldIdx )
-		{
-			if ( !strcmp(srcList_[oldIdx].identifier,
-				newSrcList[newIdx].identifier) )
-			{
-				// Add unchanged device to new context list
-				// Take from existing context list to new
-				newCtxList[newIdx].grabber = ctxList_[oldIdx].grabber;
-				newCtxList[newIdx].window = ctxList_[oldIdx].window;
-
-				found = true;
-				break;
-			}
-		}
-
-		if ( !found )
-		{
-			addition = true;
-			qDebug() << "source added:"
-				<< newSrcList[newIdx].description;
-
-			// create grabber and window (& record in ctxList)
-			createContext(&newCtxList[newIdx], &newSrcList[newIdx]);
-		}
-	}
-
-	// Don't grab mutex if not necessary
-	if ( !removal && !addition )
-	{
-		delete [] newSrcList;
-		delete [] newCtxList;
-		return;
-	}
-
-	qDebug() << "New list of sources: there were" << srcListLen_
-		<< "now there are" << newSrcListLen;
-
-	QMutexLocker locker(&sourceMutex_);
-
-	// replace old lists with new
-	delete [] srcList_;
-	delete [] ctxList_;
-	srcList_ = newSrcList;
-	ctxList_ = newCtxList;
-	srcListLen_ = newSrcListLen;
-}
-
-// get a fresh list of devices
-void
-GrabberManager::getFreshSrcList(vidcap_src_info * &pNewSrcList, int & newSrcListLen)
-{
-	newSrcListLen = vidcap_src_list_update(sapi_);
-
-	if ( newSrcListLen < 0 )
-		throw std::runtime_error("failed vidcap_src_list_update()");
-	else if ( newSrcListLen == 0 )
-		qDebug() << "no sources available";
-
-	pNewSrcList = new vidcap_src_info[newSrcListLen];
-
-	if ( vidcap_src_list_get(sapi_, newSrcListLen, pNewSrcList) )
-		throw std::runtime_error("failed vidcap_srcList_get()");
-}
-
-// used by constructor and notification callback
-void
-GrabberManager::createContext(mySourceContext *mySrcCtxt,
-		vidcap_src_info *srcList)
-{
-	QMutexLocker locker(&sourceMutex_);
-
-	mySrcCtxt->grabber = 0;
-	mySrcCtxt->window = 0;
-
-	try
-	{
-		mySrcCtxt->grabber = new Grabber(this, sapi_, srcList,
-				width_, height_, 0, framerate_);
-	}
-	catch (std::runtime_error &)
-	{
-		qWarning() << "Could not find a suitable format for device "
-			<< srcList->description << "-" << srcList->identifier;
-		return;
-	}
-
-	// Cleanup if capture stopped due to error or device removal
-	// NOTE: may be connecting before mgr construction is complete.
-	connect(mySrcCtxt->grabber, SIGNAL(captureAborted(Grabber *)),
-			this, SLOT(killGrabber(Grabber *)));
-
-	try
-	{
-		mySrcCtxt->window = new MainWindow(QString("%1 - %2")
-				.arg(title_).arg(srcList->description),
-				width_, height_);
-		mySrcCtxt->window->show();
-	}
-	catch (std::exception &)
-	{
-		qDebug() << "Could not create window for device '"
-			<< srcList->description << "' ("
-			<< srcList->identifier << ")";
-
-		delete mySrcCtxt->grabber;
-		mySrcCtxt->grabber = 0;
-
-		return;
-	}
-
-	// Start capture AFTER window is created.
-	// If capture fails, both grabber and window will be deleted.
-	try
-	{
-		mySrcCtxt->grabber->capture();
-	}
-	catch ( std::runtime_error & e )
-	{
-		qCritical() << "failed to start capture for grabber ("
-			<< e.what() << ")";
-
-		delete mySrcCtxt->window;
-		mySrcCtxt->window = 0;
-
-		delete mySrcCtxt->grabber;
-		mySrcCtxt->grabber = 0;
-
-		return;
-	}
-
-	mySrcCtxt->window->show();
-
-	// connect video to window
-	QObject::connect(mySrcCtxt->grabber,
-				SIGNAL(videoFrame(int, int, QByteArray)),
-				mySrcCtxt->window,
-				SLOT(displayVideo(int, int, QByteArray)),
-				Qt::AutoConnection);
-
-	// Set the Application icon
-	QIcon app_icon(":/app_icon.png");
-
-	// Windows and Linux need to have the icon set for the
-	// main window so it will appear in the top left corner
-	// as well as in taskbar
-	// Mac OSX windows do not usually have an icon in the title
-	// bar, so we disable that
-#ifdef MACOSX
-	mySrcCtxt->window->setWindowIcon(QPixmap());
-#else
-	mySrcCtxt->window->setWindowIcon(app_icon);
-#endif
-}
-
+#include <stdexcept>
+
+#include <QApplication>
+#include <QDebug>
+#include <QIcon>
+#include <QMutexLocker>
+
+#include "GrabberManager.h"
+
+GrabberManager::GrabberManager(QObject * parent, const QString & title,
+		int width, int height, int framerate)
+	: QObject(parent),
+	  title_(title),
+	  width_(width),
+	  height_(height),
+	  framerate_(framerate),
+	  vc_(vidcap_initialize()),
+	  sapi_(0),
+	  ctxList_(0),
+	  srcList_(0),
+	  srcListLen_(0)
+{
+	qDebug() << "Starting grabber for each capture device...";
+
+	if ( !vc_ )
+		throw std::runtime_error("failed vidcap_initialize()");
+
+	if ( !(sapi_ = vidcap_sapi_acquire(vc_, 0)) )
+		throw std::runtime_error("failed to acquire default sapi");
+
+	if ( vidcap_sapi_info_get(sapi_, &sapiInfo_) )
+		throw std::runtime_error("failed to get default sapi info");
+
+	qDebug() << "sapi:" << sapiInfo_.identifier
+		<< "|" << sapiInfo_.description;
+
+	if ( vidcap_srcs_notify(sapi_, &GrabberManager::userNotificationCallback, this) )
+		throw std::runtime_error("failed vidcap_srcs_notify()");
+
+	srcListLen_ = vidcap_src_list_update(sapi_);
+
+	if ( srcListLen_ < 0 )
+		throw std::runtime_error("failed vidcap_src_list_update()");
+
+	srcList_ = new vidcap_src_info[srcListLen_];
+
+	if ( vidcap_src_list_get(sapi_, srcListLen_, srcList_) )
+		throw std::runtime_error("failed vidcap_srcList_get()");
+
+	ctxList_ = new mySourceContext[srcListLen_];
+
+	// Rescan on notification
+	// NOTE: connecting before mgr construction is complete
+	connect(this, SIGNAL(deviceNotification()),
+			this, SLOT(rescanDevices()));
+
+	// create a grabber for each video capture device
+	for ( int i = 0; i < srcListLen_; ++i )
+	{
+		qDebug() << "src:" << srcList_[i].identifier
+			<< "|" << srcList_[i].description;
+
+		createContext(&ctxList_[i], &srcList_[i]);
+	}
+}
+
+GrabberManager::~GrabberManager()
+{
+	qDebug() << "Destroying all grabbers...";
+
+	{
+		QMutexLocker locker(&sourceMutex_);
+
+		for ( int i = srcListLen_ - 1; i >= 0; --i )
+		{
+			if ( ctxList_[i].grabber )
+				delete ctxList_[i].grabber;
+
+			if ( ctxList_[i].window )
+				delete ctxList_[i].window;
+		}
+
+		delete [] ctxList_;
+		delete [] srcList_;
+	}
+
+	if ( vidcap_sapi_release(sapi_) )
+		qWarning() << "failed vidcap_sapi_release()";
+
+	vidcap_destroy(vc_);
+}
+
+void
+GrabberManager::killGrabber(Grabber *grabber)
+{
+	//  protect context list and srcListLen_ from concurrent access
+	//       (from notification callback)
+	QMutexLocker locker(&sourceMutex_);
+
+	for ( int i = 0; i < srcListLen_; ++i )
+	{
+		if ( ctxList_[i].grabber == grabber )
+		{
+			if ( ctxList_[i].grabber )
+				delete ctxList_[i].grabber;
+			ctxList_[i].grabber = 0;
+
+			if ( ctxList_[i].window )
+				delete ctxList_[i].window;
+			ctxList_[i].window = 0;
+			break;
+		}
+	}
+}
+
+void
+GrabberManager::shutdown()
+{
+	qDebug() << "grabber manager got signal to shutdown";
+
+	// cause message loop to exit
+	QApplication::quit();
+}
+
+int
+GrabberManager::userNotificationCallback(vidcap_sapi *, void * user_context)
+{
+	GrabberManager *grabMgr = (GrabberManager *)user_context;
+
+	// trigger main thread to handle this - rescan the devices
+	emit grabMgr->deviceNotification();
+
+	return 0;
+}
+
+void
+GrabberManager::rescanDevices()
+{
+	vidcap_src_info * newSrcList;
+	int newSrcListLen;
+
+	// query for device list
+	try
+	{
+		getFreshSrcList(newSrcList, newSrcListLen);
+	}
+	catch (std::runtime_error &e)
+	{
+		qCritical() << "exception while rescanning devices:" << e.what();
+		return;
+	}
+
+	bool removal = false;
+	bool addition = false;
+	// compare each existing device to new list
+	//    If it's not there, clean it up
+	for ( int oldIdx = 0; oldIdx < srcListLen_; ++oldIdx )
+	{
+		bool found = false;
+		for ( int newIdx = 0; newIdx < newSrcListLen; ++newIdx )
+		{
+			if ( !strcmp(srcList_[oldIdx].identifier,
+				newSrcList[newIdx].identifier) )
+			{
+				found = true;
+				break;
+			}
+		}
+
+		if ( !found )
+		{
+			removal = true;
+			qDebug() << "source removed:"
+				<< srcList_[oldIdx].description;
+
+			// NOTE: Source might not be capturing when
+			// removed, so don't rely on capture callback
+			// to clean up after a device removal.
+			//
+			// cleanup after this device removal
+			killGrabber(ctxList_[oldIdx].grabber);
+		}
+	}
+
+	mySourceContext * newCtxList = new mySourceContext[newSrcListLen];
+
+	// Compare each device in new list to old list
+	// If it's new, add it to the new context list
+	for ( int newIdx = 0; newIdx < newSrcListLen; ++newIdx )
+	{
+		bool found = false;
+		for ( int oldIdx = 0; oldIdx < srcListLen_; ++oldIdx )
+		{
+			if ( !strcmp(srcList_[oldIdx].identifier,
+				newSrcList[newIdx].identifier) )
+			{
+				// Add unchanged device to new context list
+				// Take from existing context list to new
+				newCtxList[newIdx].grabber = ctxList_[oldIdx].grabber;
+				newCtxList[newIdx].window = ctxList_[oldIdx].window;
+
+				found = true;
+				break;
+			}
+		}
+
+		if ( !found )
+		{
+			addition = true;
+			qDebug() << "source added:"
+				<< newSrcList[newIdx].description;
+
+			// create grabber and window (& record in ctxList)
+			createContext(&newCtxList[newIdx], &newSrcList[newIdx]);
+		}
+	}
+
+	// Don't grab mutex if not necessary
+	if ( !removal && !addition )
+	{
+		delete [] newSrcList;
+		delete [] newCtxList;
+		return;
+	}
+
+	qDebug() << "New list of sources: there were" << srcListLen_
+		<< "now there are" << newSrcListLen;
+
+	QMutexLocker locker(&sourceMutex_);
+
+	// replace old lists with new
+	delete [] srcList_;
+	delete [] ctxList_;
+	srcList_ = newSrcList;
+	ctxList_ = newCtxList;
+	srcListLen_ = newSrcListLen;
+}
+
+// get a fresh list of devices
+void
+GrabberManager::getFreshSrcList(vidcap_src_info * &pNewSrcList, int & newSrcListLen)
+{
+	newSrcListLen = vidcap_src_list_update(sapi_);
+
+	if ( newSrcListLen < 0 )
+		throw std::runtime_error("failed vidcap_src_list_update()");
+	else if ( newSrcListLen == 0 )
+		qDebug() << "no sources available";
+
+	pNewSrcList = new vidcap_src_info[newSrcListLen];
+
+	if ( vidcap_src_list_get(sapi_, newSrcListLen, pNewSrcList) )
+		throw std::runtime_error("failed vidcap_srcList_get()");
+}
+
+// used by constructor and notification callback
+void
+GrabberManager::createContext(mySourceContext *mySrcCtxt,
+		vidcap_src_info *srcList)
+{
+	QMutexLocker locker(&sourceMutex_);
+
+	mySrcCtxt->grabber = 0;
+	mySrcCtxt->window = 0;
+
+	try
+	{
+		mySrcCtxt->grabber = new Grabber(this, sapi_, srcList,
+				width_, height_, 0, framerate_);
+	}
+	catch (std::runtime_error &)
+	{
+		qWarning() << "Could not find a suitable format for device "
+			<< srcList->description << "-" << srcList->identifier;
+		return;
+	}
+
+	// Cleanup if capture stopped due to error or device removal
+	// NOTE: may be connecting before mgr construction is complete.
+	connect(mySrcCtxt->grabber, SIGNAL(captureAborted(Grabber *)),
+			this, SLOT(killGrabber(Grabber *)));
+
+	try
+	{
+		mySrcCtxt->window = new MainWindow(QString("%1 - %2")
+				.arg(title_).arg(srcList->description),
+				width_, height_);
+		mySrcCtxt->window->show();
+	}
+	catch (std::exception &)
+	{
+		qDebug() << "Could not create window for device '"
+			<< srcList->description << "' ("
+			<< srcList->identifier << ")";
+
+		delete mySrcCtxt->grabber;
+		mySrcCtxt->grabber = 0;
+
+		return;
+	}
+
+	// Start capture AFTER window is created.
+	// If capture fails, both grabber and window will be deleted.
+	try
+	{
+		mySrcCtxt->grabber->capture();
+	}
+	catch ( std::runtime_error & e )
+	{
+		qCritical() << "failed to start capture for grabber ("
+			<< e.what() << ")";
+
+		delete mySrcCtxt->window;
+		mySrcCtxt->window = 0;
+
+		delete mySrcCtxt->grabber;
+		mySrcCtxt->grabber = 0;
+
+		return;
+	}
+
+	mySrcCtxt->window->show();
+
+	// connect video directly to window, so that a blocked
+	// main thread won't result in a pile-up of frames
+	QObject::connect(mySrcCtxt->grabber,
+				SIGNAL(videoFrame(int, int, QByteArray)),
+				mySrcCtxt->window,
+				SLOT(displayVideo(int, int, QByteArray)),
+				Qt::DirectConnection);
+
+	// Set the Application icon
+	QIcon app_icon(":/app_icon.png");
+
+	// Windows and Linux need to have the icon set for the
+	// main window so it will appear in the top left corner
+	// as well as in taskbar
+	// Mac OSX windows do not usually have an icon in the title
+	// bar, so we disable that
+#ifdef MACOSX
+	mySrcCtxt->window->setWindowIcon(QPixmap());
+#else
+	mySrcCtxt->window->setWindowIcon(app_icon);
+#endif
+}
+


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