How to get the timestamp Output.outputframe(timestamp) relative to system time clock?

[msspad]

When running the code below, cam_first_line_us starts with 0. I want to have the time relative to other IO events, respectively to the STC, is that possible? With Raspberry 3 and PiCamera, that was done with cam_first_line_us = picamera.frame.timestamp % (2 ** 32).

class ImageToTcp(Output):
	def outputframe(self, frame, keyframe: bool = True, cam_first_line_us: int = None):
		# cam_first_line_us == 0 at the first call and then increases, in microseconds
picam2.start_recording(encoder, ImageToTcp())

[msspad]

Here's how I solved it: PiCamera.Encoder._timestamp() always substracts firsttimestamp from the timestamp. To prevent this, I use JpegStcEncoder below. It seems, SensorTimestamp provides the STC.

from libcamera import controls

class JpegStcEncoder(JpegEncoder):
	def _timestamp(self, request):
		sensorTimestampNs = request.request.metadata[controls.SensorTimestamp]
		timestamp_us = round(sensorTimestampNs * 0.001)
		return timestamp_us

Minor issue with PiCamera.Encoder._timestamp, it does not round to timestamp_us:
ts = int(request.request.metadata[controls.SensorTimestamp] / 1000) # ns to us