fix video file read

video_io/sv_video_base.cpp

@@ -1172,10 +1172,13 @@ void CameraBase::open(CameraType type, int id)
   if (this->_cap.isOpened())
   {
     std::cout << "Camera opened!" << std::endl;
+    if(type != CameraType::VIDEO)
+    {
       this->_is_running = true;
       this->_tt = std::thread(&CameraBase::_run, this);
       this->_tt.detach();
     }
+  }
   else if (type != CameraType::NONE)
   {
     std::cout << "Camera can NOT open!" << std::endl;
@@ -1193,6 +1196,12 @@ void CameraBase::_run()
 bool CameraBase::read(cv::Mat& image)
 {
   if (this->_type != CameraType::NONE)
+  {
+    if(this->_type == CameraType::VIDEO)
+    {
+      this->_cap >> image;
+    }
+  else
     {
       int n_try = 0;
       while (n_try < 5000)
@@ -1207,6 +1216,7 @@ bool CameraBase::read(cv::Mat& image)
         n_try ++;
       }
     }
+  } 
   if (image.cols == 0 || image.rows == 0)
   {
     throw std::runtime_error("SpireCV (101) Camera cannot OPEN, check CAMERA_ID!");