How do you stream WebCam feed to multiple clients on the same wifi network, where client IP's can be random due to DHCP? - streaming

Question

I have a scenario where I want to stream a webcam feed to multiple display devices over a single wifi network. I've tried using UDP multicast, but it seems the wifi is flooded with packets and the video is extremely choppy or simply doesn't work. It's like I can see the first frame of the video and then maybe a few later frames, then it just stops altogether.
Currently I have three Raspberry Pi's (RPi) configured like this:
All 3 RPi's are version 4 with Raspberry Pi OS (buster), and none of them are connected to the LAN via ethernet (eth0).
The primary RPi has a webcam and also an USB wifi adapter.
◦ The wifi adapter is a Panda PAU06. [Wifi adapter link]
◦ The webcam is connected to the PRi's camera port.
[camera link]
◦ The primary RPi does not have a display, only the webcam.
◦ The internal nic (wlan0) is connected to my home router, but should not be needed in this scenario. I simply use it to connect to the RPi network, like a jump spot, for configuration purposes.
◦ The Panda nic (wlan1) uses a static IP of 192.168.44.1, and is configured as an Access Point using hostapd and WPA security.
◦ The primary RPi has DHCP configured to hand out addresses in the range 192.168.44.[10-50] on wlan1.
◦ Routing is not setup to allow the wlan1 to access the internet.
The secondary RPi's just have the internal wifi (wlan0) connecting to the primary RPi's SSID.
◦ The secondary RPI's have display's attached to them, with native resolution of 800x480. [display link]
I can ssh just fine between the three RPi's, but obviously I must connect to the primary before connecting to the other two.
This is what I've been trying to setup, but doesn't quite work right. I don't know if I'm doing something wrong, or if there's a bug in gstreamer's multicast protocol.
‣ Host with camera using multicast:
$ sudo route add 224.1.1.1 wlan1
$ gst-launch-1.0 -v v4l2src device=/dev/video0 \
! 'video/x-raw,width=800,height=480,framerate=24/1' \
! clockoverlay 'time-format=%D %H:%M:%S' \
! jpegenc ! rtpjpegpay \
! udpsink host=224.1.1.1 port=5000 auto-multicast=true
‣ Client(s) with display using multicast:
$ gst-launch-1.0 udpsrc address=224.1.1.1 port=5000 \
auto-multicast=true \
! application/x-rtp, 'encoding-name=JPEG' \
! rtpjpegdepay ! jpegdec ! autovideosink
Any comments or suggestions are greatly appreciated!
Note: Using unicast, works fine, but I can only have 1 remote connected and I have to know it's IP address in advance, which I don't because its controlled by DHCP.
‣ Host with camera using unicast:
$ gst-launch-1.0 -v v4l2src device=/dev/video0 \
! 'video/x-raw,width=800,height=480,' framerate=24/1 \
! clockoverlay 'time-format=%D %H:%M:%S' \
! jpegenc ! rtpjpegpay \
! udpsink host=192.168.44.11 port=5000
‣ Client with display using unicast:
$ gst-launch-1.0 udpsrc port=5000 \
! application/x-rtp, 'encoding-name=JPEG' \
! rtpjpegdepay ! jpegdec ! autovideosink

Answer 1

Wifi is weird for Multicast. It can hog the full bandwidth at 2.5GHZ and 20% of bandwith for 5GHz. So using unicast would be better.
You would just use tee for replicating the stream and send to each of your targets (assuming their IP addresses ending with 11,12,13):
gst-launch-1.0 -v v4l2src device=/dev/video0 \
! 'video/x-raw,width=800,height=480,' framerate=24/1 \
! clockoverlay 'time-format=%D %H:%M:%S' \
! jpegenc ! rtpjpegpay \
! tee name=stream \
stream. ! queue ! udpsink auto-multicast=0 host=192.168.44.11 port=5000 \
stream. ! queue ! udpsink auto-multicast=0 host=192.168.44.12 port=5000 \
stream. ! queue ! udpsink auto-multicast=0 host=192.168.44.13 port=5000
I'd suggest adding rtpjitterbuffer on receiver side:
gst-launch-1.0 udpsrc port=5002 auto-multicast=0 ! application/x-rtp,encoding-name=JPEG ! rtpjitterbuffer latency=500 ! rtpjpegdepay ! jpegdec ! autovideosink