PhonerLite: Codec vs Sample Rate

In the post-roll after last weeks VUC call with Michael Iedema of Askozia Project I took a little time to join the call using the PhonerLite soft phone. I didn’t tell people right away, but some later commented that I sounded like I was back to narrowband (G.711) During the formal portion of the call I was on the bridge using Eyebeam in wideband (G.722)

I was a little surprised that I was in narrowband when using PhonerLite. The only codec that I had enabled in the profile was G.722, as you can see in the following screen shot.

Although since I’ve only just been experimenting with PhonerLite for a hour or two I suspected that there was something in its configuration that I had overlooked.

This was definitely the case. Poking around the pulldown menus I discovered that the sampling rate of the audio subsystem is determined in a setting separate from the codec preferences. VUC regular Maxim sent me a note about it at about the same time that I discovered it myself.

This setting caught me completely off-guard. I’ve never seen a soft phone where the sample rate was end-user adjusted beyond selecting the codec.

However, once set to 16,000 Hz sampling I was able to rejoin the call, late in the post-call session, and the result was a bone fide wideband connection.

So, I’m happy to report that PhonerLite does in fact play nice with all of my wideband hardware and the ZipDX bridge. That means that, at least for Windows, we really do have a freely available, wideband capable soft phone. This is a great way for people to experiment with wideband on their own without needing to invest in a SIP hard phone.