message: VideoCapture test to ensure that cv::VideoCapture does not share output buffers between frames.
diff: @@ -616,4 +616,37 @@ static vector<Ext_Fourcc_API> generate_Ext_Fourcc_API_nocrash()
  INSTANTIATE_TEST_CASE_P(videoio, Videoio_Writer_bad_fourcc, testing::ValuesIn(generate_Ext_Fourcc_API_nocrash()));
  +typedef testing::TestWithParam<VideoCaptureAPIs> safe_capture;
  +
  +TEST_P(safe_capture, frames_independency)
  +{
  + VideoCaptureAPIs apiPref = GetParam();
  + if (!videoio_registry::hasBackend(apiPref))
  + throw SkipTestException(cv::String("Backend is not available/disabled: ") + cv::videoio_registry::getBackendName(apiPref));
  +
  + VideoCapture cap;
  + String video_file = BunnyParameters::getFilename(String(".avi"));
  + EXPECT_NO_THROW(cap.open(video_file, apiPref));
  + if (!cap.isOpened())
  + {
  + std::cout << "SKIP test: backend " << apiPref << " can't open the video: " << video_file << std::endl;
  + return;
  + }
  +
  + Mat frames[10];
  + Mat hardCopies[10];
  + for(int i = 0; i < 10; i++)
  + {
  + ASSERT_NO_THROW(cap >> frames[i]);
  + EXPECT_FALSE(frames[i].empty());
  + hardCopies[i] = frames[i].clone();
  + }
  +
  + for(int i = 0; i < 10; i++)
  + EXPECT_EQ(0, cv::norm(frames[i], hardCopies[i], NORM_INF)) << i;
  +}
  +
  +static VideoCaptureAPIs safe_apis[] = {CAP_FFMPEG, CAP_GSTREAMER, CAP_MSMF,CAP_AVFOUNDATION};
  +INSTANTIATE_TEST_CASE_P(videoio, safe_capture, testing::ValuesIn(safe_apis));
  +
  } // namespace
  