How to find out the delay of a stream stream?

Question

Video broadcast

I have an ip camera that broadcasts to the server, and the server to users.
To watch the video, the user uses my web interface (goes to my site and watches the video), while the rtmp stream is broadcast and played through the video.js player.
The hardware part (camera and user's computer) works quickly and there are no delays in them, and the Internet channel is the weak point.
How to find out how many milliseconds the user's video is delayed?

Answer 1

How to find out how many milliseconds the user's video is delayed?

Sometimes these are not "miles", but whole seconds ... Through RTMP, the delay is usually from 1 to 5 seconds. If you would clarify why it is needed, perhaps there would be some more accurate solutions.
And so in general, judging by the specification of the RTMP protocol, there are PING packets there. You can try to intercept them through a sniffer and measure the delay, or instead of an RTMP server, plug in some kind of stub (plug) that would send ping packets instead of video and measure the response time ...
* this is more and more "thinking out loud", t .to. the details of the question are not known and it is quite difficult (to me) to formulate some kind of "good solution".