[speex-dev] Some simple questions

John Haugeland JohnH at senscom.com
Mon Sep 15 14:55:10 PDT 2003

I'm being PHBed into a VOIP project, and Speex sprang to mind.  Bandwidth is
going to be a fairly serious issue for us.  With regards to a Speex
enc/decoder, I was wondering: Rick Kane and David Siebert have already asked
about this, but seem to have gotten very different responses - the former a
call to arms, and the latter a "well, if you do it, it'll get done."  What's
the status of Speex as a fixed point codec?  Is anything done at all?

I did find some rumblings on the dev list from April between Mark Borgerding
and B. Mitchell Loebel talking about handling fixed point, but I'm as of yet
unsure how to check on their progress, whether it's done, whether I can
help, etc.  They both seemed pretty confident, and I have high hopes that
they got it done.  ;)

The homepage suggests that Speex is appropriate for VOIP.  It seems that
most of the iPaqs, Intermecs, and Symbols (Your FAQ explicitly mentions
iPaqs as slow - ack!) use ~200mHz or ~400mHz ARM CPUs.  Is that enough for
realtime encoding *while* decoding?  If so, is there an estimate of how much
free CPU time will remain?  Enough for other simultaneous
compression/decompression?  How much effect would a fixed-point encoder have
on performance?  Should I start considering commercial codecs, such as
Nellymoser's SASE and ASAO?  Are there other free or commercial codecs I
should be looking at?  Is there maybe an analog to the comparison chart at
the website that gives performance characteristics, etc?  Or, maybe, even
just an idea of the baseline CPU that's realistic for realtime full duplex

Also, IANAL.  The xiph.org variant of the BSD license looks *really* simple,
but I'd like to check and be sure.  If I were to use Speex in a closed
source binary-only commercial product, it would be sufficient to note the
copyright and the list of conditions in the manual, yes?  (I also intend to
put the copyright notice in the about box, but since it's a handheld I
wasn't going to give up screen real estate to the stipulations.)

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