Use pthread condition to sync mask calculation with new video frame

deepseg.cc

@@ -164,6 +164,7 @@ typedef struct {
 	timinginfo_t *pti;
 	pthread_mutex_t lock_raw;
 	pthread_mutex_t lock_mask;
+	pthread_cond_t condition_new_frame;
 	bool running;
 } calcinfo_t;
 
@@ -205,6 +206,7 @@ void init_tensorflow(calcinfo_t &info) {
 
 	info.lock_raw = PTHREAD_MUTEX_INITIALIZER;
 	info.lock_mask = PTHREAD_MUTEX_INITIALIZER;
+	info.condition_new_frame = PTHREAD_COND_INITIALIZER;
 	info.running = false;
 }
 
@@ -214,6 +216,7 @@ void calc_mask(calcinfo_t &info) {
 	// copy frame from shared buffer
 	cv::Mat raw;
 	pthread_mutex_lock(&info.lock_raw);
+	pthread_cond_wait(&info.condition_new_frame, &info.lock_raw); // wait for new frame to arrive
 	raw = info.raw.clone();
 	pthread_mutex_unlock(&info.lock_raw);
 
@@ -484,6 +487,7 @@ int main(int argc, char* argv[]) {
 
 
 	bool filterActive = true;
+	calcinfo.running = true;
 
 	// mainloop
 	for(bool running = true; running; ) {
@@ -503,12 +507,10 @@ int main(int argc, char* argv[]) {
 		pthread_mutex_lock(&calcinfo.lock_raw);
 		ti.lockns=timestamp();
 		calcinfo.raw = raw.clone();
+		pthread_cond_signal(&calcinfo.condition_new_frame);
 		pthread_mutex_unlock(&calcinfo.lock_raw);
 		ti.copyns=timestamp();
 
-		// signal ai thread data arrived for the first time
-		calcinfo.running = true;
-
 		if (filterActive) {
 			pthread_mutex_lock(&calcinfo.lock_mask);
 			mask = calcinfo.mask.clone();