The red dots are VLAN 10 and yellow ones are VLAN 10. The connection between the RouterOS and OpenWRT devices is with a single wire with both VLAN in tagged.
In the remote TVBOX I have pixeled video sometimes and this is what I start looking for a solution.
In the RouterOS trunk interface there is no any dropped packets, but in the OpenWRT ones yes:
Those are dropped when received, right?.
You may have faulty cables causing errors to packet contents, or the router's CPU is too busy or something like that.
The amount is so small, less than 1/1000, that I wouldn't be too worried about it.
@hnyman brings up a very good point...because there are valid reasons for a packet to be dropped. I was going to hazard a guess for a few in the case of the OpenWrt-1 (mostly related to a movement of WiFi, IP, a cable or machine)...but realized something else...
Can you check the output for the actual VLAN also?
I change one of the OpenWRT AP for a gigabit one. Now both APs are MT7621 devices (Xiaomi Mi4A gigabit).
VLAN 10 is the LAN network, and the VLAN 30 is the VIDEO network that I see some pixeled images. Before I use the APs, I had netgear switches and there was not any pixeled image, so I can discard the wire problem (maybe the Xiaomi ethernet ports are less sensitive?)
I have no way to see the dropped packets in the VLAN30 network.
When I had Netgear switch, I have IGMP Snooping activated, but now I think it is not necessary because it is only available to enable in the LAN (VLAN 10) network. The multicast streams goes in the VLAN 30:
