[mythtv-users] Mythphone

Paul Volkaerts paul.volkaerts at lineone.net
Fri Jun 9 19:10:46 UTC 2006


> 1 - The Quickcam 4000 snd-usb-audio microphone appears
> to work based upon cat /dev/dsp1 > temp.wav than cat
> temp.wav > /dev/dsp does indeed play the audio of me
> saying "testing testing" but calling 613 doesn't seem
> to produce any noticable echo, is this normal?

If you call 613, and you hear the lady tell you you have connected to an
echo test, then after she stops speaking what you say is played back to you,
then everything is working fine!


> 2 - I have 2 machines with mythphone, 192.168.0.249
> and 192.168.0.238, both can call 613 and receive test
> calls from fwd and both are going through the firewall
> nat with port forwrding set up for 5060/21232/21234
> and 5061/22232/22234 respectively, however, things are
> very touch and go as to whether I'll get a
> bidirectional video feed.

A few points of note here ...

(a) Mythphone has no idea if a call is local to your LAN or goes through
your NAT. Therefore your machine at 192.168.0.249:21234 is NOT going to send
packets to 192.168.0.238, rather it is going to send packets to
"your-public-IP-address":21234. Your DSL router (actually your NAT device
which I assume is your DSL router) has to be clever enough to accept packets
off your LAN, NAT them, and send them back to your LAN.   Some routers do
not do this, but in your case I doubt this is a problem if it works
sometimes.

(b) If video frames are not getting through there are 3 possibilities. The
sender is not sending, the receiver is not receiving, or the network is not
networking. You need to narrow this down. The best way is the stats (hit
INFO mid-call).  Run this both ends and see what counters are counting.  If
its not obvious what they mean (there are lots of counters to trap
inter-thread issues), run a call fomr 60 seconds or so and post the results
and I'll take a look.

(c) Performance issues are often a problem.  Encoding H.263 is labour
intensive. Check your CPU levels and try smaller video sizes or lower frame
rates.  I have a 2G Pentium 4 and it runs reasonable resolution with as high
a frame rate as my camera delivers.

> Interestingly I can sometimes prompt a screen refresh
> by turning the lights on and off, wierd!

That I can't explain!  Its not on my test-plan :-)




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