Infrared sensor timestamps for D435 are not accessible

[t-fi]

Dear librealsense Team,

sadly I accidentally deleted the issue template and cannot make it come back.

My setup is:
OS: Ubuntu
Wrapper: Python3
HW: D435

I observe the following behavior both on the pipy version and a fresh local build of master with -DENFORCE_METADATA=true:

import pyrealsense2.pyrealsense2 as rs

pipe = rs.pipeline()
config = rs.config()
config.enable_stream(rs.stream.infrared, 1, 1280, 800, rs.format.y16)
pipe.start(config)

frames = pipe.wait_for_frames()
ir_l = frames.get_infrared_frame(1)

print(ir_l.supports_frame_metadata(rs.frame_metadata_value.sensor_timestamp))
print(ir_l.get_frame_timestamp_domain())
print(ir_l.get_frame_metadata(rs.frame_metadata_value.sensor_timestamp))

Will yield

False
timestamp_domain.global_time
Traceback (most recent call last):
  File "/home/oba/src/blitzr3d/tmp.py", line 14, in <module>
    print(ir_l.get_frame_metadata(rs.frame_metadata_value.sensor_timestamp))
RuntimeError: metadata not available

So, is getting the sensor timestamp (aka mid exposure timestamp) possible? Is there a setting I can use to enable the functionality?

[MartyG-RealSense]

Hi @t-fi You should not need to use the -DENFORCE_METADATA flag on Linux as it is a Windows command. To enable metadata, you should apply kernel patching when building from source on Linux. The information in the link below will hopefully be helpful to you.

#3717 (comment)

You can avoid the need to patch the kernel if you build from source using the libuvc / RSUSB backend install method, as it requires an internet connection but is not reliant on Linux versions, kernel versions or patching and includes metadata support.

#6368 (comment)

Bear in mind that there are disadvantages to the backend method as well as advantages, so it is not suitable for every project. In the link below, scroll down to the section headed What are the advantages and disadvantages of using libuvc vs patched kernel modules?

#5212 (comment)

[MartyG-RealSense]

Case closed due to no further comments received.