codecs

David Rowe On Royalty Free Codecs

What with the gathering storm that is wideband telephony there’s a lot of rumbling about codecs going on at the moment. Such discussions usually include at least a couple of open source proponents wondering why Speex is not more widespread. It’s a very good question.

Speex most commonly shows up in soft phones. That’s nice, but soft phones have limited appeal. Most people prefer hardware of some kind. That’s where Speex implementations are few and far between. This is kind of the opposite of the situation that I found with G.722. In that case I found that hardware support was good and growing, but support for it in soft phones was lacking.

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Making Use of Wideband Voice Right Now!: Gizmo5

This article was originally posted in June 2009, before Gizmo5 was purchased by Google.

gizmo5logoLast week I suggested Skype as an easy way to get started with wideband VoIP. Michael Robertson’s Gizmo5 is a great alternative to Skype.

Whereas Skype is a relatively closed network using proprietary protocols and codecs, Gizmo5 is based on SIP, a global open standard. A Gizmo5 account can be used from the Gizmo5 soft phone client or any SIP compliant device. That means that the myriad of SIP phones (hardware & software varieties) can be used with Gizmo5.

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Mythbusting HD Voice: Frequency Response vs Data Rate

snom_820_links_hoch_perspektive_200pxOne common misconception that keeps coming up is the assertion that the higher quality audio available through the use of wideband telephony (aka HDVoice) requires more bandwidth on the network. This is simply not true.

The terminology gets confusing for some folks. On the one hand we’re talking about frequency response of the audio channel being much greater, 50 Hz to >7 KHz for most wideband codecs, as compared to 300 Hz to 3.4KHz for the reference standard G.711. All that extra information has to go somewhere, right?

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Citrix Online Chooses GIPS Technologies

g2m_logoThere are few things that have improved my personal quality of life as much as Citrix® GotoMeeting® service. Before I signed up for GotoMeeting®, way back in 2004, I was spending a lot more time on airplanes visiting customer sites to troubleshoot problems.  These days most problems we can troubleshoot remotely. It’s both faster and less costly.

As GotoMeeting® has evolved they tied in an audio conferencing service, presumably a partner that provided the service through their own facilities. I tried using this a couple of times but the call quality was not great. It seemed typical of some of the lesser free conference services. So for the longest time we used a separate conference bridge, even though GotoMeeting® offered an attached service.

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Jeff Pulver on HDVoice

Today Jeff Pulver posted a blog entry giving his sense that HDVoice will spark a renaissance in the VoIP world. He feels that carriers will be able to differentiate themselves on the basis of quality and earn customer loyalty. He’s outright enthusiastic about HDVoice.

I find Jeff’s focus in this area encouraging. Jeff has a lot of clout and could help push wideband telephony into the thoughts of people who might otherwise pass it by.

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Asterisk to Support Polycom’s Siren7 and Siren14

asterisk1Just a brief news item from my notes of the December 26 VUC call with Steve Sokol. We learned that Digium is planning support for Polycom’s Siren7 and Siren14 codecs in a future release of Asterisk v1.6. These are also known as G.722.1 and G.722.1 Annex C. They offer wideband calling at bitrates much lower than G.722 calls.

Siren14 supports bitrates of 24, 32 or 48 kbps and 14 khz passband making it equally well suited to music as voice applications. Siren7 supports bitrates of 16, 24 or 32 kbps with 7 khz passband.

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