[Speex-dev] Comparison

SteveK stevek at stevek.com
Sat Jun 11 13:45:32 PDT 2005

On Jun 11, 2005, at 4:29 PM, Jean-Marc Valin wrote:

> Le vendredi 10 juin 2005 à 21:27 -0400, SteveK a écrit :
>> I'm not an expert either, but I see people choosing iLBC over speex
>> all the time with asterisk;  partly it's because they have more
>> market share in hardphones, and partly it's because of marketing and
>> such.  (another reason is that iLBC source is included in asterisk,
>> and speex is only compiled in if you have the speex development stuff
>> on your machine when you compile asterisk [i.e. the speex-devel
>> package]).   Some comments below:
> Well, it's clear that the marketing department for iLBC is a bit  
> larger
> than that for Speex ;-) I can't comment on hardphone market share  
> since
> I have no idea about the iLBC market share (or even that of Speex).
> However, I think that the (relatively recent) fixed-point should make
> Speex much more interesting for embedded devices.

It should -- but we'll have to see if it does.  iLBC is supported by  
a handful of hardphones;  I haven't heard of any that support speex yet.

>> There's a wideband version of iLBC, but it's not free(as in beer).
>> Skype uses this.  (Actually I'm not 100% sure it's called speex, but
>> GIPS makes it, and it's probably closely related).
> "Not sure it's called Speex"?? I suppose you meant something else?

Oops.  That was a thinko -- I meant I'm not sure if they just call it  
wideband iLBC, or if there's some other name for it.

>> [...]

>> since there's so many speex options, it depends on the options you
>> choose.  Asterisk presently has poor defaults, and most people link
>> against speex-1.0 code.  If you use the latest speex code, and use
>> SSE optimizations, and complexity 2, you get very comparably
>> performance from speex as compared to iLBC.  The iLBC reference code
>> is not well optimized, though.
> Not sure how speed is that relevant on a PC. With the current version,
> you can encode+decode between 50 and 150 channels (depending on
> quality/complexity), which is probably enough for most applications.

It can never be too fast :).  It's totally possible to have 4, 8, or  
12 PRI spans terminate on a single box (several quad-span PRI cards)  
and that's between 92 and 276 channels.   Coming soon are T3 cards,  
which is a few more channels again :)

With the right options, speex is competitive --  but the perception  
(at least in the asterisk community) is that it's very slow.

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