d400 series frequency depth and infra issues

[andrycapod]

Description

I am experiencing an unexpected frame rate mismatch between infra1 and depth streams when using an Intel RealSense D435i with realsense-ros2.

I would like to run both Infra1 and Depth at 848x480 @ 60 FPS, but even when explicitly setting both profiles to 60 FPS, the Infra1 stream is published at 120 Hz while the Depth stream remains at 60 Hz.

This behavior is confusing from a ROS user perspective and makes synchronization and downstream processing more difficult.

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Hardware / Software

• Camera: Intel RealSense D435i
• Firmware version: 5.17.0.9
• ROS 2 distribution: Humble
• librealsense2: 2.56.4
• realsense2-camera: 4.56.4

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Launch / Parameters

Color stream is disabled, only Infra1 and Depth are enabled.

enable_color: false
enable_infra1: true
enable_infra2: false

depth_module.infra_profile: 848,480,60
depth_module.depth_profile: 848,480,60

Observed behavior

When running the node with the configuration described above:

• The topic /camera/infra1/image_rect_raw is published at approximately 120 Hz
• The topic /camera/depth/image_rect_raw is published at 60 Hz

This occurs even though both depth_module.infra_profile and depth_module.depth_profile are explicitly set to 848,480,60.

The Infra1 stream appears to run at double the requested frame rate, while the Depth stream respects the configured FPS.

Camera logs show that both streams are opened at 60 FPS:

[component_container-1] [INFO] [1770715012.108994267] [roof_rgbd_camera]: Open profile: stream_type: Infra(1), Format: Y8, Width: 848, Height: 480, FPS: 60
[component_container-1] [INFO] [1770715012.109063389] [roof_rgbd_camera]: Open profile: stream_type: Depth(0), Format: Z16, Width: 848, Height: 480, FPS: 60

Conclusion / Question

Given the behavior described above, I would like to ask what is the correct or recommended way to use both Infra1 and Depth at 60 Hz on the D435i.

Specifically:

• Is it possible to force Infra1 to be published at 60 Hz, matching the Depth stream, when both profiles are set to 848x480@60?
• If this behavior is expected due to internal stereo/depth pipeline constraints, is there a supported configuration or parameter to keep the two streams synchronized at the same frame rate?
• If not, what is the recommended workaround to reliably use both streams at 60 Hz in ROS 2 (e.g., filtering, throttling, or alternative profiles)?

Any clarification or guidance on how to correctly achieve this setup would be greatly appreciated.

[MartyG-RealSense]

Hi @andrycapod I have not previously heard of this occurring. If it was set to 60 in the profile then it should be publishing at 60.

Did you obtain the hz value by using ros2 topic hz please?

ros2 topic hz /camera/infra1/image_rect_raw

If ros2 topic hz reports 120 hz for the infra1 stream, does the doubling still occur if you set the depth and infra1 hz to 30 in the profile?

[andrycapod]

Sorry I made a typo in writing the message.
The topic /camera/infra1/image_rect_raw is published at approximately 60 Hz
The topic /camera/depth/image_rect_raw is published at 120 Hz

this is with:

    enable_sync: False
    depth_module.infra_profile: 848,480,60
    depth_module.depth_profile: 848,480,60
    enable_infra1: True
    depth_module.emitter_always_on: False
    depth_module.emitter_enabled: 0
    decimation_filter.enable: False
    enable_color: False

ros2 topic hz /roof_rgbd_camera/depth/image_rect_raw
average rate: 120.519
	min: 0.002s max: 0.015s std dev: 0.00497s window: 121
average rate: 120.008
	min: 0.002s max: 0.016s std dev: 0.00505s window: 241
average rate: 119.907
	min: 0.002s max: 0.017s std dev: 0.00502s window: 361

ros2 topic hz /roof_rgbd_camera/infra1/image_rect_raw
average rate: 59.920
	min: 0.014s max: 0.020s std dev: 0.00101s window: 61
average rate: 59.895
	min: 0.014s max: 0.020s std dev: 0.00092s window: 121
average rate: 59.890
	min: 0.014s max: 0.020s std dev: 0.00092s window: 181
average rate: 59.891
	min: 0.014s max: 0.020s std dev: 0.00091s window: 241

If i set

    enable_sync: False
    depth_module.infra_profile: 848,480,60
    depth_module.depth_profile: 848,480,30
    enable_infra1: True
    depth_module.emitter_always_on: False
    depth_module.emitter_enabled: 0
    decimation_filter.enable: False
    enable_color: False

[component_container-1] [INFO] [1770719810.957620084] [roof_rgbd_camera]: Open profile: stream_type: Infra(1), Format: Y8, Width: 848, Height: 480, FPS: 60
[component_container-1] [INFO] [1770719810.957664447] [roof_rgbd_camera]: Open profile: stream_type: Depth(0), Format: Z16, Width: 848, Height: 480, FPS: 30

ros2 param get /roof_rgbd_camera depth_module.depth_profile 
String value is: 848,480,30

ros2 topic hz /roof_rgbd_camera/depth/image_rect_raw
average rate: 117.945
	min: 0.002s max: 0.017s std dev: 0.00510s window: 120
average rate: 113.329
	min: 0.002s max: 0.034s std dev: 0.00549s window: 229
average rate: 113.503
	min: 0.002s max: 0.034s std dev: 0.00552s window: 343

ros2 topic hz /roof_rgbd_camera/infra1/image_rect_raw
average rate: 58.037
	min: 0.014s max: 0.050s std dev: 0.00433s window: 59
average rate: 58.000
	min: 0.014s max: 0.051s std dev: 0.00440s window: 117
average rate: 58.639
	min: 0.014s max: 0.051s std dev: 0.00360s window: 177

It seems that when I set infra_profile to a frequency that differs from 30 hz the depth is affected somehow!

[MartyG-RealSense]

Thanks very much for the information. If you set depth to 30 and infra to 60, does the depth double to the desired 60 Hz?

[andrycapod]

I put this case in the previous message!
depth to 30 hz
infra1 to 60 hz
I get:
depth 120 hz
infra1 60 hz

I tried also other configuration, the test that I did :
if i set
infra1 to 30 hz
depth to 60 hz
i get
infra1 30 hz
depth 60 hz

[MartyG-RealSense]

Infra1 will always be perfectly aligned and perfectly time-synchronized with the depth map because they both originate from the left-side IR sensor of the camera. So I would recommend trusting that the two streams are synchronized despite what the depth Hz value indicates, or to use 30 Hz for both streams if you require absolute assurance.

[andrycapod]

Hello again,
I identified which parameter is causing the issue.
If I launch the driver with:
ros2 launch realsense2_camera rs_launch.py enable_infra1:=True depth_module.depth_profile:=848x480x90 depth_module.infra_profile:=848x480x90 enable_sync:=True depth_module.emitter_always_on:=False depth_module.emitter_enabled:=False
everything works correctly, and the frequencies match those specified in the depth and infra1 profiles (90 Hz).
The problem occurs when I enable:
align_depth.enable:=True
When this parameter is set, all depth-related topics are published at an incorrect frequency.
Is there an explanation for this behavior?

[MartyG-RealSense]

I'm pleased to hear that you made progress with diagnosing your issue.

I have not seen that particular behavior before when alignment is enabled and do not have an explanation for it, unfortunately.

Does the incorrect frequency also occur if you set the pointcloud publishing to true with pointcloud.enable:=true

[MartyG-RealSense]

Hi @andrycapod Do you require further assistance with this case, please? Thanks!

[andrycapod]

Yes, the frequency appears to be doubled even when I enable the point cloud.
For now, I have disabled align_depth, but I haven’t found a proper solution yetm mainly because I haven’t had the chance to dig into the code to investigate the root cause.

[MartyG-RealSense]

Okay, please do let me know if you find anything in the source code that you think may be contributing to this issue.

[andrycapod]

okay! For now we can close the issue if I find something I will open a PR, thanks

[MartyG-RealSense]

Thank you very much!