RTSP: Extract time stamp for each frame and dump video

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I am looking for a python or C++ solution for

• Dumping an RTSP stream to disk (without decoding the video)
• Extract the time stamps for each frame and store it as TXT file to disk (the camera is NTP synced)

I need this because the PC that is connected to the webcam is weak and as limited storage capactiy. For this reason, I want to dump both for later processing (there I need to know the NTP timestamp of each frame in the dumped video)