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Audio Sample Rates: Terminology vs Application

I’ve recently started to develop a grumpy streak with respect to the use of certain terminology with respect to telephony. Maybe telephony isn’t exactly the right word, let’s say that my unease arises from some odd terms surrounding audio quality in the context of communication. I think that some of the language needs to be more application sensitive.

A few years ago the world was a simpler place. The “Plain Old Telephone System” (aka POTS) was definitely a narrowband medium. Where “narrowband” implied digital sampling at 8 KHz and a useful audio channel of 300 Hz – 3,400 Hz.

Some people using more advanced systems enjoyed “wideband” audio. Wideband in that case was defined as a 16 KHz sampling yielding a useful audio channel of 50 Hz – 7 KHz. The TIA-920 standard, which I have referenced previously, spells this out. A variety of audio codecs can deliver this capability including; AMR-WB, EVRC-WB, G.722, G.722.1, CELT & Opus.

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A Digital Video Compression Primer

Canon XA10 Video CameraIn the post-roll of last week’s VUC call I got into a thread about webcams and various aspects digital video encoding.  While many in the VUC audience already have some understanding of the related principles, it occurred to me that there may be some folks that visit this site who would be interested a primer on the basics of video compression.

Then by some serendipitous twist I found this video on the subject by Drew Tyler, Instructor of Digital Media at Weber State University in Utah. He covers the basics in a pretty good live presentation, even if he is a bit of an Apple fan-boy.

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Answering A Few Questions About HDVoice

Some time ago over in the VOIP Forum at Broadband Reports there was an interesting thread about wideband telephony and it’s relationship to common ITSPs. The person who started the thread was surprised to find that they could not pass wideband audio between two accounts on the same SIP-based ITSP.


Holy cow, I just tried to pass G722 and Speex wideband through and it choked !! I can’t believe it, I thought they were supposed to be one of the more competent providers.

This person’s presumption was that if the call is between accounts at the same service provider it doesn’t traverse a media gateway, and so should support any desired codec. While the logic was basically sound, clearly this wasn’t the case as the person soon found out.

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FSCOMM: A New Open Source Soft Phone Based Upon FreeSwitch

A little over a year ago I lamented the sad state of the telecom realm with respect to soft phones, and specifically wideband audio support in soft phones. In the passing year considerable progress has been made.

Counterpath, true to their word, released retail versions of Eyebeam & Bria that support G.722…at least on Windows. Similar wideband support on the Mac platform is now in beta, or so we’ve heard.

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Zoiper Softphone Goes HD In A Big Way!

zoiperHere’s the headline:

Zoiper is the First 3rd Party Softphone to Support Skype’s SILK, Polycom’s SIREN and the Broadvoice Codecs

How does that sound? Pretty major, right? Wanna know more? Here are the details.

Given that ZoIPer Communicator is available in web, Windows, Mac & Linux flavors this could jump them to the head of the class for HDVoice support in a soft phone. And of course, ZoIPer Communicator has long supported both SIP and IAX protocols. Yes, you have options. Very nice.

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Blabbelon In SILKy Wideband Audio

blabbelonVUC regular Tim Panton has been very busy lately. He was at Astricon where he gave a splendid presentation on the current state of Skype-For-Asterisk, including a live demo of it integrated with Google Wave. He later gave a similar presentation at eComm in Amsterdam, including a demo to the Google Wave team! Of course, we’ve been using his G.722 capable Java plug-in for web browser access to the ZIPDX wideband conference bridge for several months. That has been a genuinely useful bit of software, allowing anyone with a headset & decent broadband to experience HDVoice first hand.

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