Started implementation of Video Chat (not working yet!).

- GUI part is done
- implemented a very basic JPEG codec
- added echo frame in configuration panel
- created a video capture object that uses OpenCV (should be cross systems)
Remains to do:
- serialise and send frames through p3VoRS
- use a serious codec (e.g. Theora+x264)
- add icons to reflect camera state (failure/working/sending/...)
- compilation on windows 



git-svn-id: http://svn.code.sf.net/p/retroshare/code/trunk@7449 b45a01b8-16f6-495d-af2f-9b41ad6348cc

plugins/VOIP/gui/QVideoDevice.h

@@ -0,0 +1,52 @@
+#pragma once 
+
+#include <QLabel>
+
+class VideoEncoder ;
+class CvCapture ;
+
+// Responsible from displaying the video. The source of the video is
+// a VideoDecoder object, which uses a codec.
+//
+class QVideoOutputDevice: public QLabel
+{
+	public:
+		QVideoOutputDevice(QWidget *parent) ;
+		
+		void showFrame(const QImage&) ;
+};
+
+// Responsible for grabbing the video from the webcam and sending it to the 
+// VideoEncoder object.
+//
+class QVideoInputDevice: public QObject
+{
+	Q_OBJECT
+
+	public:
+		QVideoInputDevice(QWidget *parent) ;
+		~QVideoInputDevice() ;
+
+		// Captured images are sent to this encoder. Can be NULL.
+		//
+		void setVideoEncoder(VideoEncoder *venc) { _video_encoder = venc ; }
+
+		// All images received will be echoed to this target. We could use signal/slots, but it's
+		// probably faster this way. Can be NULL.
+		//
+		void setEchoVideoTarget(QVideoOutputDevice *odev) { _echo_output_device = odev ; }
+	
+		void start() ;
+		void stop() ;
+
+	protected slots:
+		void grabFrame() ;
+
+	private:
+		VideoEncoder *_video_encoder ;
+		QTimer *_timer ;
+		CvCapture *_capture_device ;
+
+		QVideoOutputDevice *_echo_output_device ;
+};
+