GIPS webinar on Wideband Voice

GIPS yesterday sponsored a webinar on HD voice in the teleconferencing and videoconferencing industries. It was introduced by Elliot Gold of Telespan Publishing. Elliot made the point that HD video will be running at 90% of video equipment sales by the end of this year, and that HD audio is at least equally important to the user experience and should be the next technology transformation in the equipment and services markets.

Dovid Coplon of GIPS gave a more technical presentation, starting with a very accessible explanation of the benefits of HD audio.

Dovid made some interesting observations. He named some users of GIPS wideband technology including Google Talk and Yahoo Messenger. He cited a May 2009 poll that showed 10% of respondents used HD audio all the time or whenever they could. To me this is a surprisingly high number, possibly reflecting a biased poll sample, or perhaps a large number of respondents that didn’t understand the question.

Dovid compared the benefits of the GIPS wideband codecs, iSAC and iPCM-WB. iSAC is a lower-bit-rate, higher complexity codec than IPCM-WB. Dovid pointed out that with IP packet overhead being so high, decreasing the bit-rate of a codec is not as useful as one might think. The implication was that the lower complexity of IPCM-WB outweighed its bandwidth disadvantage in mobile applications. He also included a codec quality comparison chart based on a MUSHRA scale. The chart predictably showed iSAC way better than any of the others, and anomalously showed Speex at 24 kbps as inferior to Speex at 16 kbps.

Dovid also echoed all the codec engineers I have talked with in emphasizing that the codec is a small piece of the audio quality puzzle, and that network and physical acoustic impairments can have a greater effect on user experience.

You can download the slides here.

Leave a Reply

Your email address will not be published. Required fields are marked *