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Leanne asks what HD VoIP is, and PhoneBoy responds that it probably doesn’t mean much.  Wideband CODECS have been around for ages, but because most calls terminate on the PSTN where the standard is 64k G.711 encoded at 8 bits, the fact that a PC-based client can generate and receive wideband audio is meaningless. 

I’ve sent mail to Iristel to find out what their HD VoIP is.  It could be one of three things, in my opinion:

  1. Better handling of audio on the PC itself.  Both GIPS and Diamondware have convincingly shown that audio quality can be dramatically improved by paying attention to jitter, and other parts of the audio subsystem, not just the CODEC.  This would impact all calls made, not just calls from one Iristel customer to another.
  2. A wideband CODEC.  As noted previously, this only has an impact if both users are on PC’s capable of supporting that wideband CODEC.
  3. Bog standard G.711 throughout their network.  Some operators will use more highly compressed audio on various legs throughout the network, resulting in lower quality.  If Iristel were to do this, it would undoubtebly improve quality, but they wouldn’t be the only ones to try this gambit. 

Bottom line, as Luca Filigheddu says, it’s marketng.  Whether it will be effective marketing remains to be seen, but it’s definitely marketing. 

UPDATE: I’ve just contacted Iristel.  The solution is G.722, and uses Polycom IP phones.  I’ve just ask them to confirm that it requires a Polycom IP phone at either end.

{ 10 comments… add one }

  • JohnS February 5, 2007, 5:24 am

    Hi Alec,

    BT's fusion product uses wideband (G722 or iSAC I think) for VoIP to VoIP calls, there is a huge improvement in voice quality. As you point out, the codec used in the PSTN is G711 so wideband calls are not possible from VoiP->POTS. So, not just marketing, VoIP->VoIP calls can be of much, much higher quality than POTS/mobile.



  • JohnS February 5, 2007, 5:42 am

    Hi Jason,

    You should really try it before making your mind up – there is a huge difference in quality, the CD/AM radio analogy is apt. I was very surprised at just how much better the call quality is.


  • Jason Yeung February 5, 2007, 6:56 am

    Testing something here…hope this doesn't work.


  • Jason Yeung February 5, 2007, 9:40 am

    Marketing indeed. Big deal if the difference is barely audible (if at all). G.711 is perfectly adequate for phone calls. In their press release, they say it’s like comparing “CD quality voice to an old AM radio”. Pfft…yeah, right.

    – Jason

  • Jason Yeung February 5, 2007, 9:45 am


    Hmm..interesting. I guess if you’re calling on-net it might make a difference. Never used a wideband codec though myself…G.711 has always been adequate for me.

    – Jason

  • Jason Yeung February 5, 2007, 10:54 am

    <<You should really try it before making your mind up – there is a huge difference in quality, the CD/AM radio analogy is apt. I was very surprised at just how much better the call quality is.>>

    I’ll try it out sometime and see ;)…thanks.

    – Jason

  • Thomas Howe February 5, 2007, 11:12 am

    No, I think it’s a lot more than marketing, for a number of important reasons. First, by any objective measure, wide band audio is valued by users. My evidence – Polycom. The reason they exist is because of high quality audio. Polycom’s sister, competitor and now spouse, PictureTel, existed because of high quality audio. Secondly, if you believe in the convergence of entertainment and communications, then how could you be happy with 3khz ring back tones? Finally, we have precedent for carrier’s attempts at selling higher quality audio because of these reasons. Remember that ATT thing? I think it was True Voice. For them, it wasn’t higher bandwidth, it was deeper bass. But, whatever, quality sells.

    Jason – If you heard Polycom’s HD demo at any of the latest tradeshows, you wouldn’t dismiss it.

  • PhoneBoy February 5, 2007, 2:10 pm

    One reason to care about wideband codec is if you are doing an interview for a podcast. That’s one reason so many podcasters use Skype. The audio quality is much better than many of the alternatives.

  • max March 14, 2007, 11:49 pm

    i think it does not need PolyCom phones… if there is a standard (G.722), any device that supports the standard should work in a similar fashion, no? Of course, using models / brands specified by the Service Providers should result in better technical assistance… if problems do happen along the way.

    I had a try with the BT Hub recently and it was touted to offer HD Sound. It was good! The comparison between CD and AM radio was justifiable.

  • seba April 16, 2007, 7:11 pm

    Is this codec free or you have to pay a license to be able to use it? I’ve just checked its quality in a Thomson IP phone and i think it’s a great improvement, particularly when listening music through the phone (for what?that’s another issue 😛 ).

    I’d like to use this in a SIP Server (open code) that i’m modifying to broadcast audio channel within SIP sessions (you know what i mean? I’d explain better in spanish… sorry) ç

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