refactor: improve webcam thread execution and frame handling

source/webcam.cpp

@@ -38,12 +38,12 @@ void ProcessWebcamThread::Execute() {
 	bool temp_not_finish = true;
 	bool temp_pause = true;
 	bool temp_record_frame = false;
+	float frame_clock = 0.0f;
 	current_frame_clock = 0.0;
 	//construction LUT pour synchro avec la clock squirrel
 	std::ofstream lutFile(outputVideoName+"_lut.bin", std::ios::binary);
 	__LOG_CAM__ << "NEW RECORDING THREAD "<<videoIndex<<" LAUNCHED \n";
 
-	int frame_index = 0;
 	while (temp_not_finish) {
 
 		mutex_not_finish.Lock();
@@ -54,17 +54,25 @@ void ProcessWebcamThread::Execute() {
 		temp_pause = pause;
 		mutex_pause.Unlock();
 
+		// Drainer la camera en permanence, meme en pause : si on lit pas, la file
+		// du driver grossit et les frames récupéres ensuite dates du passé, ce qui
+		// decale la video par rapport a la clock (derive qui s'accumule)
+		if (!InputVideo->grab()) {
+			Platform::Get().Sleep(10);
+			continue;
+		}
+
 		mutex_record_frame.Lock();
 		temp_record_frame = record_frame;
+		frame_clock = current_frame_clock;
+		record_frame = false;
 		mutex_record_frame.Unlock();
 
-		if (temp_pause || !temp_record_frame)
-			Platform::Get().Sleep(10);
-		else{
-			InputVideo->read(*im);			
-			outputVideo->write(*im);
-
-			lutFile.write(reinterpret_cast<const char*>(&current_frame_clock),sizeof(float));
+		if (!temp_pause && temp_record_frame) {
+			if (InputVideo->retrieve(*im)) {
+				outputVideo->write(*im);
+				lutFile.write(reinterpret_cast<const char*>(&frame_clock), sizeof(float));
+			}
 		}
 	}
 	__LOG_CAM__ << "THREAD STOPPED "<<videoIndex<<"\n";
@@ -251,11 +259,13 @@ bool Webcam::Open(int width_, int height_) {
 	int device_id = -1;
 	for (int i = 0; i < id_devices.size(); i++)
 	{
-		InputVideo->open(id_devices[i]);
+		// CAP_DSHOW : meme ordre d'enumeration que la blacklist DirectShow ci-dessus
+		// et pas de waitlist interne qui prend du retard
+		InputVideo->open(id_devices[i] + CAP_DSHOW);
 		if(InputVideo->isOpened()){
 			device_id = id_devices[i];
 			break;
-		}	
+		}
 	}