Graves On SOHO Technology

This week saw an announcement about the release of Ekiga v4.0. This is the most significant release of the venerable open source soft phone in some time. It brings with it many improvements.

I’m especially interested in the following new capabilities:

• New audio codecs: SILK (used by skype), G.722.1 (aka Siren 7), G.722.2 (aka GSM-AMR Wide band)
• Video codecs changes: H.264 optimizations
• Added RTP TOS support
• Support for DNS SRV caching

While developed primarily on Linux Ekiga has long supported multiple platforms. I took a short while today to try the new release on an older Windows XP laptop. The Windows installer also installed the GTK libraries necessary to support the application. Installation was quick and painless.

Once installed I skipped the automatic process of signing up for a free Ekiga.org SIP account, instead adding credentials from one of my OnSIP extensions. In just a few moments Ekiga was registered with OnSIP allowing me to make a few brief test calls

My initial calls were to the ZipDX wideband demo. This SIP accessible service (sip:wbdemo@conf.zipdx.com) plays a number of recordings, allowing you to toggle between wideband (G.722) and narrowband (G.711) modes. Upon answering it reports the codec in use giving immediate confirmation of a wideband connection.

It also has a couple of test functions, including the ability to confirm that a client handles SIP re-invites correctly. Happily Ekiga v4.0 handled both kinds of SIP re-invites without losing the call media.

My next test call was to a Polycom VVX-1500. It was using G.722 just to confirm baseline HDVoice capability and interop with SIP hard phones. Call quality to the VVX was good, showing none of the problems the can happen with unfortunate G.722 implementations.

I then added a Logitech Webcam Pro 9000 as a video device. This admittedly older webcam was the only one that I had on hand that was also on the Ekiga approved hardware list.

Restarting Ekiga it found the camera and allowed me to make a video call to the VVX-1500. Ekiga video defaults to 320 x 240 pixels resolution (QVGA)which is exactly what the VVX-1500 likes.

Unfortunately, after just a few seconds sending video the video stream stopped. It’s not yet clear why this happened. It could be that my four year old HP 8510W laptop wasn’t up to the task. It could also be that the Wifi network created too much variability in bandwidth. I’ll try Ekiga on a newer system some time soon.

It was at first unclear how the developers could include support for G.722.2 (AMR-WB) when that wideband codec is known to be patent encumbered. The ever insightful James Body provided the answer. Ekiga uses the OPAL Plug-In for Intel Integrated Performance Primitives. This library is licensed such that it’s free for non-commercial purposes.

Since AMR-WB is the most common wideband codec deployed in mobile phones, it’s availability in a free soft phone provides some opportunity for experimentation.