Cannot open RTSP stream from `tof_depth` camera

griffin

Hello all,

I am having some issues getting the TOF camera to stream it's data over RTSP.

I have a systemd process enabled to start up a voxl-streamer instance in /etc/systemd/system/voxl-streamer-tof-depth.service

#
# Copyright (c) 2021 ModalAI, Inc.
#

[Unit]
Description=voxl-streamer
SourcePath=/usr/bin/voxl-streamer
After=voxl-wait-for-fs.service
Requires=voxl-wait-for-fs.service

[Service]
Restart=no
User=root
Type=simple
PIDFile=/run/voxl-streamer.pid
ExecStartPre=/bin/sleep 5
ExecStart=/usr/bin/voxl-streamer -s -p 8902 -i tof_depth

[Install]
WantedBy=multi-user.target

When I try to open this stream using a gstreamer command gst-launch-1.0 rtspsrc location=rtsp://<my-drone-ip>:8902/live latency=0 ! "application/x-rtp, encoding-name=RAW, format=(string)GRAY8" ! videoconvert ! autovideosink I get a generic gstreamer error.
When I inspect that systemd status using systemctl status voxl-streamer-tof-depth I see internal errors of voxl-streamer:

● voxl-streamer-tof-depth.service - voxl-streamer
   Loaded: loaded (/usr/bin/voxl-streamer; enabled; vendor preset: enabled)
   Active: active (running) since Wed 2025-02-26 19:50:20 UTC; 14min ago
  Process: 1469 ExecStartPre=/bin/sleep 5 (code=exited, status=0/SUCCESS)
 Main PID: 1957 (voxl-streamer)
    Tasks: 0 (limit: 4915)
   CGroup: /system.slice/voxl-streamer-tof-depth.service
           ‣ 1957 /usr/bin/voxl-streamer

Feb 26 19:50:31 m0054 voxl-streamer[1958]: ERROR:   Frame size mismatch: got 43200 bytes from pipe, expected 38528
Feb 26 19:50:31 m0054 voxl-streamer[1958]: ERROR:   Most Likely the publisher of the camera data made a mistake
Feb 26 19:50:31 m0054 voxl-streamer[1958]: ERROR:   Shutting down voxl-streamer
Feb 26 19:50:31 m0054 voxl-streamer[1958]: Trying to quit g main loop due to program shutdown
Feb 26 19:50:31 m0054 voxl-streamer[1958]: cleaning up gstreamer
Feb 26 19:50:31 m0054 voxl-streamer[1958]: gst_rtsp_media_take_pipeline: assertion 'GST_IS_PIPELINE (pipeline)' failed
Feb 26 19:50:31 m0054 voxl-streamer[1958]: can't create pipeline
Feb 26 19:50:31 m0054 voxl-streamer[1958]: rtsp client disconnected, total clients: 0
Feb 26 19:50:31 m0054 voxl-streamer[1958]: no more rtsp clients, closing source pipe intentionally
Feb 26 19:50:31 m0054 voxl-streamer[1958]: Exited Cleanly

Note that when I use a similar gstreamer commands (adapted for h264) I am able to open other video streams without issues.

Additionally, since upgrading to SDK 1.4.1 from 1.3.5 whenever I run voxl-inspect-cam -a after approx 30s of running the camera servers all disconnect and a wall of:

Most likely the server stopped without cleaning up
Client is cleaning up pipes for the server
ERROR in pipe_client_open opening request pipe: No such device or address

appears. Should I be concerned?

griffin

pinging @tom

Eric Katzfey

@griffin Is this on a Starling 2 drone?

griffin

@Eric-Katzfey yes it is on a starling 2 max SKU: MRB-D0012-4-V2-C29-T9-M24-X0

tom

@griffin Are you able to view the tof data in voxl-portal?

griffin

@tom yes

Alex Kushleyev

@griffin , please see the following post with the same symptom and fix : https://forum.modalai.com/topic/4171/frame-size-mismatch-got-43200-bytes-from-pipe-expected-38528

We will test this and merge to dev soon, meanwhile if you can re-build the camera server, you could test it.

Alex

griffin

Hey @Alex-Kushleyev

I finally found some time to test out the fix and got it working, but only after some additional modification: the voxl-camera-server seems to encode the frames as 240x180 when they are actually 180x240. This led to weird aliasing issues when inspecting the resulting RTSP streams.

The fix was just for me to swap the WxH resolutions. I am not 100% sure if this would be necessary to do in all cases but might be worth you looking into

Kind regards,
Griffin

Alex Kushleyev

Hi @griffin, thank you for confirming. You are absolutely right.

I will make an update to the original fix and test myself. The fix should be checking the flag (configInfo.en_rotate) and rotating the output dimensions in the pipe json, if needed.

Alex

Alex Kushleyev

the fix has been committed to voxl-camera-server dev branch : https://gitlab.com/voxl-public/voxl-sdk/services/voxl-camera-server/-/commit/520bad13a573dde500d36cf1008e67102e0b6078 . I tested it for the rotated and non-rotated use case using voxl-streamer.

Alex