Jason Aarons (US) wrote: > My understanding is Skype's secret is using the iLBC codec, which Cisco > has also licensed for their 79X2 models as well. I travel and lot and > in places where Yahoo Phone Out or MSN Phone or Cisco IP Communicator > will fail the Skype client will work. The iLBC codec can really handle > packet loss.
AFAIK, not iLBC, but another GIPS codec. ILBC is present in some grandstream phones from what I remember, not in the Cisco 7912 as one example, not sure about other phones. In a word with still many PSTN gateways out there that don't support it, ILBC in the SIP UA side only can help that much :-).. > > Skype High Quality Video with the Logitech Orbit AF on both ends is > awesome. I got my family a set for Fathers day. Just amazing video > quality. Uses a On2 VP-7 codec that has much lower cpu and other > benefits over h.264. > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Steve > Underwood > Sent: Saturday, July 12, 2008 3:30 AM > To: Asterisk Users Mailing List - Non-Commercial Discussion > Subject: Re: [asterisk-users] MagicJack quality > > Tzafrir Cohen wrote: >> On Sat, Jul 12, 2008 at 10:26:24AM +0800, Steve Underwood wrote: >> >>> C. Savinovich wrote: >>> >>>> I am puzzled by the quality of magicjack. I keep trying to figure > out how >>>> they can the quality be that adequate. Since Skype also has an > excellent >>>> quality, that leaves me to believe that software based calls > (softphones) >>>> could have and advantage over hardphones, provided there is a > parameter that >>>> those 2 companies are addressing. >>>> >>>> Anyone's thoughts on this? >>>> >>>> CS >>>> >>>> >>> I don't know what Magic-jack does (I've never actually seen one), but > I >>> know the key thing about Skype that impresses people - its wideband >>> voice codec. A lot of people poo-poo the idea that wideband voice has > >>> value in a phone call. They are either close to deaf, or have never >>> tried it. Clarity is profoundly improved. Skype seems to use various >>> tricks to keep the packet flow smooth, but its wideband that makes it > >>> sound better than the PSTN. >>> >>> You might think a standard phone plugged into an adaptor, like a >>> Magic-jack, would be limited to narrow band voice, as that is all the > >>> phone was designed for. It turns out most phones only aggressively >>> filter at the low end of the band. They let a lot of energy above > 4kHz >>> through, and they do generally sound better through a wideband codec. >>> >>> Many modern line interface chips are actually capable of running in a > >>> 16k samples/second mode, even though most are programmed for 8k >>> samples/second. I think the ones on the TDM400P type cards can. Some >>> from Silicon Labs certainly can, and chips from Zarlink and others > can. >>> >> The DAA in those cards can work in 16Hz. So they can send higher > quality >> samples to the telco. Provided Zaptel supports it. But then again, it >> will get lost as soon as it gets converted to digital at the telco, >> right? >> > I guess I wasn't clear. What I said was only useful for a SLIC to phone > connection. It won't be of any benefit for a DAA to PSTN exchange > connection, for the reason you state. >> Anyway, the ProSLIC chip does not seem to support it. >> > Silicon Labs make a Wideband ProSLIC, Si 3216, which is, er, wideband. > As I said before, Zarlink and other make them too. > > Regards, > Steve _______________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- AstriCon 2008 - September 22 - 25 Phoenix, Arizona Register Now: http://www.astricon.net asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
