[discussion] retrieve rtsp ntp time

[ramoncaldeira]

Hi!

I have a use case where I would benefit from retrieving the camera's NTP time from a RTSP container. FFMPEG contains structures capable of parsing this information, but unfortunately they are internal and are not available in the public API.

I made this small patch to solve my problem. It is not generic enough, as it hardcodes ntp time into demux return. I also had to include vendor/ffmpeg-4.2 in include_dirs on setup.py.

My intention with this PR is to share the solution with you and hopely find out a way to change the code so that it can be incorporated into the project.

[ramoncaldeira]

Run failed because of fatal error: libavformat/rtsp.h: No such file or directory.
This was expected, due to the private structures.

I tested the code myself with this snippet and it worked:

import av

input_ = av.open('RTSP_URL')

for (ntp, packet) in input_.demux(video=0):
    print('ntp', ntp)
    print('packet', packet)

[Hobeom]

I used your branch to download the video stream with RTSP. The returned ntp value is as follows, how should I interpret it?

...
1627412725.1005974
1627412724.9732378
1627412725.1492114
...

[ramoncaldeira]

@Hobeom It's time in seconds since epoch. You can use this converter: https://www.epochconverter.com/.

[samyhocine]

A very useful commit, unfortunately it fails completing the checking part :/

[jlaine]

I'm sorry but I don't see this PR going anywhere, it completely changes the API.

[jimibit]

Hi!

I have a use case where I would benefit from retrieving the camera's NTP time from a RTSP container. FFMPEG contains structures capable of parsing this information, but unfortunately they are internal and are not available in the public API.

I made this small patch to solve my problem. It is not generic enough, as it hardcodes ntp time into demux return. I also had to include vendor/ffmpeg-4.2 in include_dirs on setup.py.

My intention with this PR is to share the solution with you and hopely find out a way to change the code so that it can be incorporated into the project.

Great !!
Very very useful.
Does this patch work in Windows ? Is it up-to-date ?

Jim