Missing function in VideoCapture getRTPTimeStampTs()

I’m using cv2.VideoCapture(rmtp_source) to get rmtp video stream and I need to extract the timestamp of each frame.
I google around and find some examples using functions:
which seems to fit my requirements.

However, I have tried OpenCV 4.5.1 / 3.4.1 but they all complains:
“AttributeError: ‘cv2.VideoCapture’ object has no attribute ‘getRTPTimeStampTs’”
Any suggestion where these function locate?

b.t.w. I noticed another option: timestamp = cap.get(cv2.CAP_PROP_POS_MSEC). But this value is relative to the start of video, in our rtmp streaming case, it is when I pull the stream not when the stream starts.

those functions do not exist in the opencv api, and unless you start to use ffmpeg or gstreamer directly (w/o VideoCapture) you cannot access them, sorry for the bad news ;(

… ofc. you can try to hack your own , gl.