The past couple of days I’ve been playing around with the Gizmo5 client on my desktop. It’s actually pretty slick. I wanted to see if I could pass a wideband call to/from Gizmo5 from my Polycom 650s or Eyebeam. So far no joy. There seems to be a problem completing a call from Gizmo5 to OnSIP via SIP URI. The call rings on the IP650 but cannot be answered. Not certain if its an issue with Polycom firmware or both devices being behind the same NAT and trying to connect directly. I’ll try and work that out when I’m back at home.
A quick search of the Gizmo5 knowledgebase reveals that they support a handful of codecs, including the GIPS iSac, the wideband adaptive codec made popular by Skype. In their early days if there was one big reason why Skype calls sounded better than the PSTN iSac was likely it.
It is curious that Gizmo5 goes to the trouble of supporting iSac, which I presume has some cost when they don’t support G.722. That could be implemented with little or no cost as there’s no licensing or royalties involved. Here’s the list of codecs they support:
- GSM — fixed bit rate, not loss tolerant, narrow band (8khz sampling rate).
- iSAC — variable bit rate, loss tolerant, narrow and wideband (8 to 16khz). Varies based on Bandwidth, packet loss, delay*
- iLBC — variable bit rate, loss tolerant, narrow*
- PCMA — fixed bit rate (8kHz sampling rate)
- PCMU — fixed bit rate (8kHz sampling rate, high band width)
- IPCMWB — 16 kHz sampling rate*
- EG711 (enhanced g711) — fixed bit rate, loss tolerant, narrowband
- iPCM — fixed bit rate, loss tolerant, wide band.*
Those marked with * are from the GIPS codec family. Their other software component offering is “NetIQ” an adaptive jitter buffer and packet loss concealment module.
This seems like an oversight so I’ve shot an email to Gizmo5 suggesting that G.722 support be added in the future. They might well consider G.722.1 under it’s new royalty-free terms. But royalty-free is not the same as zero cost so that may be a stretch.