Re: [tlug] 7/10 TLUG Technical Meeting - voice communication questions

[Jake Morrison <jake_morrison@example.com>]

Codec licensing is a serious pain for VoIP. 

G.711 is freely available, but requires 64 kbps of 
bandwidth. GSM is free and low bandwidth (around 
5 kbps), but is low quality. The best low-bit-rate 
codecs (G.723.1 and G.729) are patented and require 
complex DSP algorithms. IP Phones normally require DSP
hardware to implement them, though a server can handle
a fair number of calls in software. 

Speex is a good, free low bit rate codec, but so far is
only supported in free software. I expect this to change
as more phone manufacturers use open source. 

The big vendors (TI, Broadcom) got their 
patented algorithms made into standards, and 
they are using them to charge a tax on anyone 
who wants to implement the standards.

Most manufacturers get the DSP libraries along with the 
DSP hardware, which is made by the people with the patents.
They don't actually give you a license, you get 
"patent indemnification". Which means that they will cover
you if you are sued, which they do by using their cross licensing
agreements. So they don't have to pay any license fees, it is
all profit for them. 

Paying for the licensing separately is expensive and still risky,
as there are lots of patents around and nobody will license all of
them to you. Digium (the people behind Asterisk) sells G.729
licenses for US$10/port. The patent licensing is about equal to
the cost of the hardware now. 

What a scam! When you see these kinds of games, you start to 
understand why people in developing countries lose respect for
for western IP. 

Jake