ModalAI Forum

I've downloaded the drivers (imx412_drivers_20260529). How do I install and select them?

To make sure I understand this, I still publish messages from the application processor with the application processor time and PX4 will correct it? Then do the PX4 messages coming out (like with attitude data) then have the timestamp correct relative to the application processor, or do I need to convert those timestamps?

I was able to get the visual odometry message updating the PX4 EKF2 and that seems like the better path. Just to make sure I've got this set up correctly, I put the application processor time (CLOCK_MONOTONIC) into the timestamp field and the mavlink server updates the message with the appropriate PX4 kernel time before forwarding it to PX4?

Can you post the changes required for the /usr/lib/camera sensormodules to reduce the EMI?

I am new to VOXL development and am working on an application that will provide a VISION_POSITION_ESTIMATE mavlink message to the autopilot and control the aircraft via OFFBOARD commands. The application will run on the VOXL. I am currently reading frames from the MPA, synchronizing with metadata from MPA, and computing a vision based position estimate. However, I am struggling with how to get that position estimate to the autopilot and how to configure the autopilot to receive them.

• Do I use the mavlink_onboard pipe to send the mavlink offboard control commands (ex. SET_ATTITUDE_TARGET) and VISION_POSITION_ESTIMATE messages?
• Are there instances where I should communicate over UDP with the autopilot or are all comms done through MPA?
• Is there example code to follow with instructions on any internal routing or other setup?

Thanks

As an update, I was able to get the latency down to about 50-60ms by making the following changes to /etc/modalai/voxl-camera-server.conf. Are there any other optimizations I can make?

{
"type": "imx412",
"name": "hires_down",
"enabled": true,
"camera_id": 2,
"fps": 10,
"en_preview": true,
"preview_width": 4056,
"preview_height": 3040,
"en_raw_preview": false,
"en_small_video": false,
"small_video_width": 1024,
"small_video_height": 768,
"small_venc_mode": "h264",
"small_venc_br_ctrl": "cqp",
"small_venc_Qfixed": 30,
"small_venc_Qmin": 15,
"small_venc_Qmax": 40,
"small_venc_nPframes": 9,
"small_venc_mbps": 2,
"small_venc_osd": false,
"en_large_video": false,
"large_video_width": 4056,
"large_video_height": 3040,
"large_venc_mode": "h264",
"large_venc_br_ctrl": "cqp",
"large_venc_Qfixed": 40,
"large_venc_Qmin": 15,
"large_venc_Qmax": 50,
"large_venc_nPframes": 29,
"large_venc_mbps": 40,
"large_venc_osd": false,
"en_snapshot": false,
"en_snapshot_width": 4056,
"en_snapshot_height": 3040,
"exif_focal_length": 3.0999999046325684,
"exif_focal_length_in_35mm_format": 17,
"exif_fnumber": 1.2400000095367432,
"snapshot_jpeg_quality": 75,
"ae_mode": "lme_msv",
"gain_min": 54,
"gain_max": 8000,
"ae_desired_msv": 60,
"exposure_min_us": 20,
"exposure_max_us": 33000,
"exposure_soft_min_us": 5000,
"ae_filter_alpha": 0.600000023841858,
"ae_ignore_fraction": 0.20000000298023224,
"ae_slope": 0.05000000074505806,
"ae_exposure_period": 1,
"ae_gain_period": 1
}

voxl-inspect-cam -a shows that the hires_down_large_color latency is >900ms. What is the cause of the latency and can it be reduced?

Thanks!