Opencv + GStreamer lagging exactly two seconds behind gst-launch


I’m trying to capture live feed through an h264 camera on RTSP protocol. On a terminal, the following gst-launch-1.0 command gives almost real-time feed:

gst-launch-1.0 playbin uri=rtsp://IP:PORT/live uridecodebin0::source::latency=0

When I put in the converted URL into OpenCV VideoCapture, it works but is always exactly two seconds behind. The following two URLs seem to give the same result:

cv2.VideoCapture("uridecodebin uri=rtsp://IP:PORT/live latency=0 ! videoconvert ! appsink")
cv2.VideoCapture("rtsp://IP:PORT/live", cv2.CAP_GSTREAMER)

Is there something like, OpenCV is maintaining a buffer of the video? Or is the converted URL missing something? If the first case is true, can the buffer be removed?

I have also built the latest FFmpeg but the same problem exists. This problem is seen on h264 but the problem reduces on a mjpeg stream, a lot.

My configuration is:
CPU: i7-8xxx
GPU: GTX-1060 6GB