Luckfox Forums

While developing a custom video streaming app using gstreamer I encounter problem. Using udpsink to send jpeg compressed video stream to host PC via Ethernet cable (both PC and board connected to router in local network with 1m cat5 cables), all works fine. I get solid 30 fps, network shows around 30-40 Mbit/s load. But I need to place the camera in an electrically isolated environment, so I decided to use a 1Gbit media converter to send signal over fiber. The network topology is next:

Luckfox board -> media converter -> (fiber) -> media converter -> router -> PC

Ethtool shows that eth0 interface is in 100Base-TX, full duplex with flow controll for tx and rx and autonegotiation on.
And my framerate becomes uneven jumping all over the place, sometimes receiver program won't start displaying video at all (Gstreamer on receiving side throw warnings about missing rtp headers).

I use iperf3 to check udp packet loss and they were around 5-10%, sending packets from board to PC no mater if it's 90 Mbit/s or 5 Mbits/s. Ethtool show no dropped packets in internal buffers. When I tested the network in the opposite direction, there were no loses even at 95 Mbit/s. I replaced board with notebook and tested again, no loses in both directions at 90 Mbit/s. So i'ts looks like the problem is not in media converter. Also i tested different cables, connecting board to converter with 10cm one.
Next I tried setting eth at 10Base-TX full duplex with flow control and autonegotiation on on board . There we no packets losses, but max bitrate is 9.5Mbits which is not enough for me.
The question is, why packets lost with board but not with notebook. For me it's looks like some problem with flow control. Board sending packets to fast and overflows media converter buffer (Btw media converter is on RTL8213b ic) and they are simply dropped, but I am not a big expert in networks and Linux in general. I don't understand why everything works fine when there are no mediaconverter.
I hope that someone can help me with this issue.

It's looks like some electrical/interference/signal integrity issue. After removing RJ45 magnetics and connecting directly to media converter, packet loss dropped to 0.1-1%.
Btw, with luckfox pico mini, there are no packet loss.

Hello, RV1103/RV1106 are equipped with built-in Phy. Therefore, theoretically, the Ethernet control pins directly connected to the chip have the lowest loss.
We need to take into account the majority of users' requirements for network cables. Finally, considering the cost, volume, and protection of the chip pins, we choose the RJ45 connector with a network transformer.
Unfortunately, there is no better solution for the Ethernet packet loss problem you encountered at present.

Crocodile wrote: ↑2025-09-30 7:53 Finally, considering the cost, volume, and protection of the chip pins, we choose the RJ45 connector with a network transformer.

They could have used RJ-45 with LEDs