[Telepathy] change speexenc settings for empathy

Alexey Fisher bug-track at fisher-privat.net
Sat Apr 9 01:05:25 PDT 2011


Am Freitag, den 08.04.2011, 21:57 +0200 schrieb Alexey Fisher:
> Am Freitag, den 08.04.2011, 12:16 -0400 schrieb Olivier Crête:
> > On Fri, 2011-04-08 at 17:57 +0200, Alexey Fisher wrote:
> > > Hi
> > > Am Freitag, den 08.04.2011, 11:42 -0400 schrieb Olivier Crête:
> > > > > dtx=1
> > > > > # do not send any packets on silence
> > > > > # see Bug https://bugzilla.gnome.org/show_bug.cgi?id=646474
> > > > 
> > > > This gives you the impression that the bitrate is lower because you
> > > > don't send why not speaking. But it doesn't change the maximum bitrate
> > > > (when speaking) which is all that really matters for quality..
> > > >
> > > > It will also break if WMM is enabled, in that case, the wireless router
> > > > only sends out frames when it receives one, so you have to send
> > > > continuously to keep on receiving.
> > > 
> > > My fault in description. It send about 2 packets/sec to keep connection.
> > 
> > That's not enough.. You won't get incoming packets unless you send
> > outgoing packets.. so if you send 2 packets per second, it means you
> > only get incoming packets twice per second, which will destroy your
> > audio.
> > 
> > Unless someone tells me there is a reliable way to temporarily disable
> > WMM from an application, DTX is not usable with WiFi networks.
> 
> Hmm, i'm confused.
> if i understand correctly, the behavior like: 2 packets send / 2 packets
> receive can be caused by firewall.

I digget i bit deeper in the firwall issue. It called "NAT traversal" or
"UDP hole punching". TO keep the hole in firewall/nat we need only send
empty udp packet.

So this will still reduce the traffic, but also keep as possible to keep
connection open. This is mach better then doing that what we do now.

So the scenario is like this:
1) speex recognize silence and setting GAP flag on the packet
2) current rtp, by default, will not send packets with GAP
 so it should be changed to produce keep alive packet or some thing
similar
3) we do not need to pack empty rtp packet in udp. We can just send
empty udp. So UDP should some how be noticed about it.


> WMM is completely  different. WMM make sense only on the air, between AP
> and client. If AP was configured correctly (my dd-wrt seems not
> configured at all), it will map DSCP numbers to WMM (0x18->BE; 0x10->
> BG; 0x28->VI; 0x38-> VO). Empathy do not set DSCP, Skype do not do it
> too. It seems like some/all ISP ignore DSCP or reset it to 0. So WMM or
> DSCP do not make any difference.
> 
> So i do not understand how this two thing connected.

-- 
Regards,
        Alexey



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