5 FPS is the lowest you can go I think. But you could try it and test it for yourself.
I know the steps are a bit tricky cause I had a hard time understanding too. So here goes
SSH into OpenWRT
This mean you need to connect to the Yun SSH interface, so open putty for windows, and SSH to the IP of the YUN. So in my case it was ssh 192.168.240.1. That's going to get you in the linux part of the Yun, or as they call it the OpenWRT.
Install either the UVC driver (if not already installed) e.g. opkg install kmod-video-uvc
where i need to install them? and how?
That's the hardest part to understand. What you need to do is get the package from here https://www.dropbox.com/sh/6nv5f2datb3n2ps/nj-z27B6i1 download all the ipk to your desktop. Then you can put them on a MicroSD. Take that MicroSD and put it in the Arduino.
2- Then you need to mount the MicroSD, you need to type those commands in putty while connected to the openWRT. The commands you need to type are in bold
- add your micro sd card (it should appear as /dev/sda1 by default)
- Create a folder or mount point /mnt/sda1 (mkdir /mnt/sda1)
- mount your sd card - mount /dev/sda1 /mnt/sda1
3- Then you need to install those package. So you need to go in the /mnt/sda1 and install all the packages. And you do it like that : opkg install mjpg-streamer.ipk.
So start by the first one and go down the list. Don't worry if you install one package and you get an error message saying that you need another package before. Just install the Pre-Requisit and after re-install the one that fail. In the end all the package should install.
4- Once all that's done type mjpg_streamer -i "input_uvc.so -d /dev/video0 -r 640x480" -o "output_http.so -p 8080 -w /mnt/share"
and you should be all set.
Hope it helps