Image not retrieved when using simulation time

[iripatx]

Hello and thank you all beforehand,

I've been using video_stream_opencv for retrieving video on a NVIDIA AGX Xavier Jetson from an IP camera, it works just perfectly.

Now I'm trying to set up a global clock for message syncronization on multiple machines using the timestamps on the messages. After some research, I found that you can set the use_sim_time parameter for nodes to listen to the /clock topic (more about this here). This way, all nodes should use the same time.

However, when using this method, the video_stream_opencv node doesn't publish anything. This is what the nodes outputs when running it:

process[hallway_cam/hallway_cam_stream-1]: started with pid [2892]
[ INFO] [1621502184.390573120]: Initializing nodelet with 8 worker threads.
[ INFO] [1621502184.761711424]: Camera name: hallway_cam
[ INFO] [1621502184.761863072]: Provided camera_info_url: ''
[ INFO] [1621502184.761924032]: Publishing with frame_id: hallway_cam
[ INFO] [1621502184.761973952]: Setting camera FPS to: 30
[ INFO] [1621502184.762024608]: Throttling to fps: 30
[ INFO] [1621502184.762195072]: Setting buffer size for capturing frames to: 100
[ INFO] [1621502184.762302464]: Flip horizontal image is: false
[ INFO] [1621502184.762405152]: Flip vertical image is: false
[ INFO] [1621502184.762487808]: Video start frame is: 0
[ INFO] [1621502184.762531744]: Video stop frame is: -1
[ INFO] [1621502185.304085152]: using default calibration URL
[ INFO] [1621502185.304503360]: camera calibration URL: file:///root/.ros/camera_info/hallway_cam.yaml
[ INFO] [1621502185.304866560]: Unable to open camera calibration file [/root/.ros/camera_info/hallway_cam.yaml]
[ WARN] [1621502185.305000832]: Camera calibration file /root/.ros/camera_info/hallway_cam.yaml not found.
[ INFO] [1621502185.305481248]: Opening VideoCapture with provider:
[ INFO] [1621502186.699953376]: Video stream provider type detected: rtsp_stream
[ INFO] [1621502186.700295424]: Camera reports FPS: 180000

Note that the output lines with the image dimensions are missing.

The node is launched with almost default params. This is my launch file:

<param name="use_sim_time" value="true"/>

<!-- Video input node -->
<include file="$(find video_stream_opencv)/launch/camera.launch" >
    <arg name="camera_name" value="hallway_cam" />
    <arg name="video_stream_provider" value="<my RTSP stream>" />
</include>

The system is unaffected if the other nodes use simulation time, it's only this node's problem.

Please tell me if you need more information, and thank you very much.