[Asterisk-biz] $19.95/mo unlimited US IAX termination

[Michael Giagnocavo]

>On Fri, 2005-04-08 at 09:33 -0500, Brian West wrote:
>> Speex is a CPU whore.  Even more so than g729.
>
>How much of a whore are we talking about here? Clock cycles are cheap,
>so if I can get 7 channels of speex with a dual 900Mhz PIII (my current
>system) I'd say it's worth the savings in bandwidth.
>
>FWIW, I just spoke to VoicePulse and their engineering department said
>they will support Speex with IAX termination within 1 to 2 days.
>
>-lee

It's about 3 times worse than G729 for encoding and just a tad bit faster on
decoding. So, from a provider's standpoint, that means reduced capacity per
machine, which in turn means higher overhead and less profit. Usually when
you work out rates, you'll get your codecs worked out too. If your provider
has to do expensive CPU work, expect to pay for it. Then again, if you're
not running tons of traffic, it might just not make enough difference and
they probably play the average (considering some use ULAW and some GSM,
which could balance out your Speex usage).

Just for comparison, here's a complete "show translation" table:

         Translation times between formats (in milliseconds)
          Source Format (Rows) Destination Format(Columns)

         g723   gsm  ulaw  alaw  g726 adpcm  slin lpc10  g729 speex  ilbc
   g723     -     4     2     2     3     2     1     7    11    31    18
    gsm    12     -     2     2     3     2     1     7    11    31    18
   ulaw    12     4     -     1     3     2     1     7    11    31    18
   alaw    12     4     1     -     3     2     1     7    11    31    18
   g726    13     5     3     3     -     3     2     8    12    32    19
  adpcm    12     4     2     2     3     -     1     7    11    31    18
   slin    11     3     1     1     2     1     -     6    10    30    17
  lpc10    13     5     3     3     4     3     2     -    12    32    19
   g729    13     5     3     3     4     3     2     8     -    32    19
  speex    12     4     2     2     3     2     1     7    11     -    18
   ilbc    14     6     4     4     5     4     3     9    13    33     -

Speex is definitely the worst performer here, as far as CPU time goes.
(These numbers from a P4 2.4GHz, using Digium's G729 P4 codec, and Intel's
G723, 5.3 rate, optimized for P4, and Speex 1.0.4-1, Asterisk
CVS-HEAD-04/11/05-19:24:17).

-Michael