cv::VideoCapture.read(frame) with CAP FFMPEG and hardware acceleration adds two black lines

C++
1

We read mp4 video frame by frame with cv::VideoCapture.read like this :

cv::VideoCapture capture = cv::VideoCapture(cv::String(“video.mp4”),   cv::CAP_FFMPEG,{cv::CAP_PROP_HW_ACCELERATION,cv::VIDEO_ACCELERATION_ANY});

if (capture.isOpened())
{
   while (!isEndVideo)
   {
      (…)
      cv::Mat frame;
      capture.read(frame);
   }
}

Frame retrieved have 2 black lines on the bottom while on the video those 2 black lines are not present.

Our video is a fullHD video (1920x1080).

If we don’t use hardware acceleration, those 2 black lines are not present. If we pass a video 1920x1088 with hardware acceleration, those 2 black lines are no present.

We need to use hardware acceleration for performance reasons, and size of our video can’t be changed. Is it a bug ? Is there a way to get around this problem ?

Environment : Windows / C++ / OpenCV 4.13.0

Thanks.