How do I get a timestamp from a frame?

[NikitaDS01]

Overview

Hello everyone. The problem is that I somehow need to get the timestamp from the video stream using Python. The only way I've seen and am using is this one: link. In it he modifies the ffmpeg log where he outputs ts to the console. And in Python, we use Popen to intercept this value.

if( nal->type == 6 ) {
	uint64_t* ts = (uint64_t*)(nal->data+3);
	av_log(logctx, AV_LOG_DEBUG,
            	"nal_unit_type: %d(%s), nal_ref_idc: %d, ts: %"PRId64"\n",
            	nal->type, h264_nal_unit_name(nal->type), nal->ref_idc, *ts );
	return 1;
}

Other than that, I didn't find anything. Although I'm sure it can be obtained somehow without using other sub processes (I want to believe).

Investigation

I used these methods to get a timestamp:

• I tried to get it by extracting it from an unregistered SEI. However, the side data in the frame was empty.
• I tried to get them by converting the packets to bits and doing a search there. It didn't work out. I probably don't have enough knowledge.
• I've tried using other libraries. But either they didn't help, or they didn't work as they should.

Research

I have done the following:

• Checked the PyAV documentation
• Searched on Google
• Searched on Stack Overflow
• Looked through old GitHub issues

Additional context

I would also like to note my observation that when using this command:
ffmpeg -i input-url -c:v copy -bsf:v trace_headers -f null -

this error. If this is a problem for getting ts, then it will be sad and i will have to leave the current method.

[trace_headers @ 0x60c6025132c0] User Data Unregistered
[trace_headers @ 0x60c6025132c0] Invalid SEI user data unregistered payload.
[trace_headers @ 0x60c6025132c0] Failed to read unit 2 (type 6).
Error applying bitstream filters to an output packet for stream #0:0.