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VOXL Flir UVC Video Streaming (RTSP)

Table of contents

  1. Overview
  2. Requirements
    1. Hardware
      1. Boson
      2. Lepton
    2. Target Software
    3. Host Software
  3. Setup Hardware
  4. Network Configuration
  5. Run Software on Target
    1. voxl-uvc-server
      1. Configure voxl-uvc-server
      2. Configure voxl-streamer
  6. Viewing Stream
    1. VLC
    2. QGroundControl


This user guide provides the necessary steps to stream Flir Boson or Lepton over RTSP network using the USB UVC interface and the VOXL system.

In short, we’ll be doing the following:

  • Connect a Flir USB camera to the VOXL’s V2 Debug Board
  • Use voxl-streamer on the VOXL to stream the video to the host computer
  • Use either VLC or QGC on a host computer to view the video stream



Part NumberDescriptionLink
Host ComputerGround Control Station (Ubuntu 18.04) 
VOXL-DKVOXL Development KitPurchase
MPS-00001-15V/6A Power SupplyPurchase
MCBL-00009-1USB Cable (Host, 4-pin JST to USB 2.0 Type A Female)Purchase
Flir Boson or Flir Lepton  


The Boson requires more current than the USB 2.0 standard supports. To achieve this current, the power and ground can be connected separately in a “y-cable” to an alternate 5V power source. Alternatively, ModalAI has a debug board with a direct connection to the core 5V supply on VOXL which provides enough current. This Debug Board V2 can be found below.

Part NumberDescriptionLink
MDK-M0078-2VOXL Debug Expansion V2 Add-onPurchase


One of the following VOXL Add-on boards is required.

Part NumberDescriptionLink
MDK-M0048-1-01VOXL Microhard Modem Add-onPurchase
MDK-M0017-1-01VOXL USB Expansion Board with Fastboot and Emergency BootPurchase
MDK-M0030-1-01VOXL Cellular LTE and USB hub add-onPurchase

Target Software

VOXL-SDK version XXX or greater.

Host Software

  • On the host computer, install VLC media player, which we’ll used to display the RTSP video:
sudo apt-get install vlc

Setup Hardware

  • Disconnect power from the VOXL
  • Attach the Debug Board to VOXL J13
  • Attach the JST cable to the JST USB connector
  • Set the jumper to 5V APM setting
  • Attach the Flir camera to the USB connector on the JST to USB Female A cable
  • Connect power to the VOXL


Network Configuration

  • Configure the VOXL as an Access Point (or connect it to a network)
    • instructions on how to do this are here
    • the default IP address of the device will be
  • Connect the host computer to the VOXL’s Access Point (default password is 1234567890) or to the same network you connected the VOXL to

Run Software on Target


  • SSH onto the target (see here for details) or ADB in using a micro-usb to USB cable
  • First, validate the the USB device is found using the lsusb command:
root@apq8096:~# lsusb

Configure voxl-uvc-server

Start voxl-uvc-server with the following command


voxl-uvc-server -r 640x512


voxl-uvc-server -r 160x120 -f 9

More details in the voxl-uvc-server documentation.

Configure voxl-streamer

Start voxl-streamer with the following command


voxl-streamer -c uvc-flir-boson


voxl-streamer -c uvc-flir-lepton

More details in the voxl-streamer documentation.

Viewing Stream


  • On the host system, run the VLC software

  • Go to Media > Open Network Stream

  • Enter the following URL: udp://@:4242

  • Click Play to view the video stream


Before attempting to view the video stream, follow these instructions on connecting to QGC: How to Connect QGroundControl to VOXL using WiFi

  • After your connection has been established to QGC, press the purple QGC logo in the top left corner in order to access the Application Settings menu.

  • Under the General tab, scroll down until you find the Video section.

  • Under the Video Source dropdown, choose RTSP (h.264) Video Stream.

  • In the UDP Port field enter the default: 4242

  • You will now be able to view the video stream under QGC’s Fly view.

Next: Connecting VOXL to Flight Core