fix video file read

video_io/sv_video_base.cpp

@@ -1172,9 +1172,12 @@ void CameraBase::open(CameraType type, int id)
   if (this->_cap.isOpened())
   {
     std::cout << "Camera opened!" << std::endl;
-    this->_is_running = true;
-    this->_tt = std::thread(&CameraBase::_run, this);
-    this->_tt.detach();
+    if(type != CameraType::VIDEO)
+    {
+      this->_is_running = true;
+      this->_tt = std::thread(&CameraBase::_run, this);
+      this->_tt.detach();
+    }
   }
   else if (type != CameraType::NONE)
   {
@@ -1194,17 +1197,24 @@ bool CameraBase::read(cv::Mat& image)
 {
   if (this->_type != CameraType::NONE)
   {
-    int n_try = 0;
-    while (n_try < 5000)
+    if(this->_type == CameraType::VIDEO)
     {
-      if (this->_is_updated)
+      this->_cap >> image;
+    }
+  else
+    {
+      int n_try = 0;
+      while (n_try < 5000)
       {
-        this->_is_updated = false;
-        this->_frame.copyTo(image);
-        break;
+        if (this->_is_updated)
+        {
+          this->_is_updated = false;
+          this->_frame.copyTo(image);
+          break;
+        }
+        std::this_thread::sleep_for(std::chrono::milliseconds(20));
+        n_try ++;
       }
-      std::this_thread::sleep_for(std::chrono::milliseconds(20));
-      n_try ++;
     }
   } 
   if (image.cols == 0 || image.rows == 0)