using G729 or iLBC most likely won't help. I'm using both G729 and iLBC
and the bandwidth used is around 35kbps and 20kbps respectively (give or take some)
So you will "save" 50 or 70kbps. If the issue of your voice chopinness is due to packet drops
due to some overload on one of the boxes, then the above savings won't make much of dent
because the core issue of packet drops won't be addressed.
I'm not using mifi and neither had so some of the question are shooting a bit in the dark:
1. you reported originally that when there is a call going on and then someone tries to access the net
the available bandwidth drops significantly: what if there are mutliple people in the house
that do some net access at the same time? in that case the throughput remains high? did you measure
what the throughput is when one computer is just measuring bandwidth while the others are accessing the internet?
2. given what you said that you tested with DD-wrt and experimented with some equipment rearrangement,
the one component that is common across your experiments is the MiFi thingy. So may be
it is doing some throttling or tries to act super smart with the traffic that goes through it?
(btw, I had seen a situation where my cable box would crash when I'll use Google drive. Not
the same problem you see but it was in the same class of "what the heck" moments)
Here is one thing to try. It's not a solution yet but more trying to figure out what is going on.
You reported that when a call is going on and someone access the net the available bandwidth
is something like 2mbps. So let try to do the following: can you apply a bandwidth limiter (aka shaper)
for the outgoing traffic on all the ports on your router and set it to something like 1mbps ?
The theory here is that, even if netgear or dd-wrt or Obi is prioritizing traffic, the traffic
load that arrives at mifi is lets say 15mbps. But you also reported
that when a call is going on, the available bandwidth gets down to 1-2Mbps. So, lets drop the "aggregate" traffic that is going to hit mifi before it gets merged with the rest of your home traffic. So do explore
if you can set bandwidth limits on the ports and try the above. Depending on the outcome
and measurements, we will try to determine the next step.
btw, do you hear the audio chopiness on your end? or the other end reports chopiness to you ?
L.