Wifi Problems on iOS
Over time we have learned alot about what causes issues with WIFI communications to ATEM switchers from iPads.
Ultimately it comes down to short latencies and interruptions in the WIFI communications. How much this happens seems to depend alot on your WIFI Router.
The ATEM protocol is highly intolerant of connected clients which don't respond to every message in an appropriate timeframe. This means that if your WIFI connection is interrupted, even quite briefly, the ATEM will reject the client connection.
As a comparison - TCP/IP connections and protocols are designed to deal with this sort of thing, with the connection 'guaranteed' to deliver the data (whilst the socket connection is maintained), and most TCP servers and clients have reasonable timeouts to allow for network disruptions of a few seconds.
However, the ATEM protocol uses UDP, where its possible (even common) for data packets to fail to arrive at their destination. The ATEM protocol does have a retry mechanism for this, but its not very patient. Also, even delayed (not lost) packets can cause the ATEM to get quite stroppy and reject a client connection.
To add to this, the iOS operating system appears to be messing with the WIFI to try and save power. We think its trying to turn the WIFI transmitter off as much as possible and this can lead to delays when the transmitter comes back on. This delay can be enough to annoy the ATEM and cause a client disconnect. Its likely that this explains why you may get slightly better results on a laptop since the WIFI may be more 'consistent'.
In the most recent versions of Strata Pro, Lite and View, we have added a new preference 'HOTLINK' which tries to discourage iOS from turning off the WIFI transmitter. We have also added a 'connection latency' indicator to Strata Pro. HOTLINK can improve connectivity in many cases. The latency display allows you to best position yourself relative to the router and other equipment and also detect things which are increasing latency (even without causing disconnect).
In addition further testing with different routers re-enforces the fundamental advice about the WIFI network. Our experience with several routers suggests that an Apple Airport is significantly more reliable than some other (high quality) routers, even over longer distances. Whilst an ATEM disconnect may happen in minutes with one vendor's router, it can stay connected for hours via an Airport in the same environment.
Clearly the ATEM protocol was designed to run on wired network connections with zero packet loss and very low latencies. Running this over a wireless connection requires some care to create as clean a network as possible with minimal interruptions caused by interference, or other WIFI influencing agents.
If you want to control your ATEM wirelessly, spend a little time experimenting with different routers, and use the latency indicator on Strata Pro to judge how well you are doing. Test have shown that Apple Airport routers appear to work significantly better than others in this regard. We dont know why - maybe some secret sauce in the Apple WIFI communications.
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