reverted the original VideoCapture::read() code; moved frame index check to…

reverted the original VideoCapture::read() code; moved frame index check to where it should belong: ffmpeg wrapper; applied patch by Rob Reilink (ticket #1971)

modules/highgui/src/cap.cpp

@@ -494,15 +494,8 @@ bool VideoCapture::retrieve(Mat& image, int channel)
 
 bool VideoCapture::read(Mat& image)
 {
-    double frame_pos = get(CV_CAP_PROP_POS_FRAMES);
-    double frame_count = get(CV_CAP_PROP_FRAME_COUNT);
-    if (frame_pos < frame_count || frame_pos < 0 || frame_count < 0)
-    {
-        if(grab())
-            retrieve(image);
-        else
-            image.release();
-    }
+    if(grab())
+        retrieve(image);
     else
         image.release();
     return !image.empty();

modules/highgui/src/cap_ffmpeg_impl.hpp

@@ -438,6 +438,10 @@ bool CvCapture_FFMPEG::grabFrame()
     const int max_number_of_attempts = 1 << 16;
 
     if( !ic || !video_st )  return false;
+    
+    if( ic->streams[video_stream]->nb_frames > 0 &&
+        frame_number > ic->streams[video_stream]->nb_frames )
+        return false;
 
     av_free_packet (&packet);
     

modules/highgui/src/cap_qtkit.mm

@@ -316,7 +316,9 @@ int CvCaptureCAM::startCaptureDevice(int cameraNum) {
 	capture = [[CaptureDelegate alloc] init]; 
 	
 	QTCaptureDevice *device; 
-	NSArray* devices = [QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeVideo];
+    NSArray* devices = [[[QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeVideo]
+	        arrayByAddingObjectsFromArray:[QTCaptureDevice inputDevicesWithMediaType:QTMediaTypeMuxed]] retain];
+	
 	if ([devices count] == 0) {
 		cout << "QTKit didn't find any attached Video Input Devices!" << endl; 
 		[localpool drain];