Speex dev - Sep 2005 - Multi-Channel/Stream support?

Hi all,

I'd like to know how well Speex handles multiple input streams. More 
specifically, if i have 4 streams that are playing at "the same time",
how
well does the CODEC handle switching from one stream to the next to process 
the audio.

The reason i ask is this....My project up until now uses the MELP CODEC 
which didn't specifically have the ability to handle multiple streams.
I'd
give the CODEC a packet to process from Stream #1, then i'd give it a packet
from Stream #2 and just keep cycling through my different input streams. The 
problem was that MELP used a lot of global variables for state information 
(basically to bookmark the audio information of that packet) and the end 
result was a lot of clicking since it's saved bookmarks were not correct 
since i changed streams on it. I had to remove every single global and move 
them to a class that i wrote so that each stream would have it's own set of 
globals to bookmark audio in.

If speex is not subject to this type of problem that would make me very 
happy. If it works similar to MELP and i have to remove all of the globals 
myself again, i'd like to know in advance.

Thanks in advance,
Chris
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://lists.xiph.org/pipermail/speex-dev/attachments/20050912/7c21f69d/attachment.htm

Hi,

Speex does have memory just like most other codecs. However, the
implementation is made such that all the codec state is contained in a
"state variable", so if you have multiple streams, all you have to do
is
create one encoder/decoder state for each stream.

	Jean-Marc

Le lundi 12 septembre 2005 ? 14:41 -0400, Chris Serio a ?crit
:
> Hi all,
> 
> I'd like to know how well Speex handles multiple input streams. More
> specifically, if i have 4 streams that are playing at "the same
time",
> how well does the CODEC handle switching from one stream to the next
> to process the audio. 
> 
> The reason i ask is this....My project up until now uses the MELP
> CODEC which didn't specifically have the ability to handle multiple
> streams. I'd give the CODEC a packet to process from Stream #1, then
> i'd give it a packet from Stream #2 and just keep cycling through my
> different input streams. The problem was that MELP used a lot of
> global variables for state information (basically to bookmark the
> audio information of that packet) and the end result was a lot of
> clicking since it's saved bookmarks were not correct since i changed
> streams on it. I had to remove every single global and move them to a
> class that i wrote so that each stream would have it's own set of
> globals to bookmark audio in. 
> 
> If speex is not subject to this type of problem that would make me
> very happy. If it works similar to MELP and i have to remove all of
> the globals myself again, i'd like to know in advance.
> 
> Thanks in advance, 
> Chris
> _______________________________________________
> Speex-dev mailing list
> Speex-dev@xiph.org
> http://lists.xiph.org/mailman/listinfo/speex-dev
-- 
Jean-Marc Valin <Jean-Marc.Valin@USherbrooke.ca>
Universit? de Sherbrooke