Monthly Archives: June 2013

Audio Codes Offer First Signs Of Hardware Support for Opus Codec

AUDIO-CODES-420HD-300pxOne of the first interesting things to arise out of this weeks WebRTC conference in Atlanta is an announcement from Audio Codes that they will be adding support for the Opus codec to their 400HD series of SIP desk phones. Here’s the press release.

There seems to be a little confusion about what’s actually going to be offered.  The title of the release states, “AudioCodes Announces WebRTC Phone.” The copy goes on to describe that the hardware will be extended to provide native support the Opus codec. This capability is projected to be deliverable in Q4-2013.

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Video Calling 1: People Just Don’t See Me In The Right Light

polycom-hdx-4500-photo-01-300pxSince taking up my new gig with ZipDX and Polycom a splendid HDX-4500 has graced my home office. It’s without question the most sophisticated end-point device that I’ve encountered. It’s a real treat to use, especially since I do so many calls using video these days.

The HDX is large enough that it gets a desk of it’s own, located across the room from my primary desk, desktop PC et al. When I’m using the HDX I always have my laptop on that desk as well.

The trouble is that I’ve had some difficulty getting the lighting correct for video calls. I’ve muddled along trying different solutions with what I’ve had on-hand, and playing with moving things around the space. Recently I’ve come to think that I need to take more significant steps to provide consistently good lighting.

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New Protection For Our Androids

nexus-7-nexus-4Not long ago Ed Tyson of Expert Shield contacted me with an offer of his companies screen protection for our Android devices. As our various phones (Nexus 4) & tablets (Nexus 7) are presently naked(!) I decided to take him up on his offer. We’re just awaiting arrival of the goods.

In the past I have used Skinomi Techskin and found them quite good. I once again reached for their products when I shattered the glass back on my Nexus 4 some weeks ago. The carbon wrap is still working great to hold the broken back together.

That said, I found that the clear protective layer for the front of the phone was a bit on the thick side. While it worked well enough as protection I found that it felt a little gummy to the touch. It subtly changed the feel of the phone in use, something that I’d like to avoid if possible.

Stella and I were initially using the Poetic Borderline Bumper case for Google Nexus 4 but we both stopped using them in recent weeks. Stella found that it made the power and volume buttons awkward to access. Mine simply tore near the power connection, then started to come apart.

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Freeswitch En Route To Support For G.719 Codec

VVX_1500_D_Freeswitch.jpgThink back to the handful of new audio codecs that have been released over the past few years; CELT, SILK and Opus to name a few. Then there are the handful of proprietary codecs that have become available under more attractive licenses. Polycom’s Siren family come to mind on that front. In all of these cases I have observed that the Freeswitch development team are typically amongst the very first to implement any new codec.

In recent weeks they have added support for G.719, an ITU standard codec created by Polycom and Ericsson. With a  sample rate of 48 KHz, G.719 is a full-bandwidth codec, supporting a useful audio channel of 20 Hz- 20 KHz. It does so with end-to-end delay of only 40 ms and at bit rates from 32 kbps to 128 kbps. It also supports stereo audio.

Upon completion of the ITU standards process Polycom published a white paper on the codec; G.719: The First ITU-T Standard for Full-Band Audio (pdf).

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Confirming The Quality Of One’s Tools

Zoom-H2-Nexus7-AudioTool.jpgWhen experimenting with a new audio path I like to take measurements. Long ago, in an age of techno-pre-history known as the late 1980’s,  I craved what were then an emerging class of computerized test instruments, like the Audio Precision System One. Happily, today such costs are unwarranted given the current class of programmable smart devices. I’ve been very happy with Audio Tool For Android running on my Nexus 7 tablet.

If I am to trust the measurements that Audio Tool allows me to make I need to start by confirming the validity of it’s measure using a known reference signal. I was also making use of the Zoom H2 Handy Portable Stereo Recorder, so I decided to record the output of the sweep generator in Audio Tool to the H2. Then I tool the resulting WAV file into Adobe Audition to see what resulted.

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