[asterisk-dev] Wideband (G722) MeetMe

Tue Jun 23 18:08:23 CDT 2009

Hi,

I asked this on asterisk-users list but did not get a definitive answer. On 1.6.2, does Meet-me bridge support native WB mixing (meaning no downscaling to SLIN) for G722 or any other WB codec ? I tried 1.6.2 Beta3 but it sounded like it was still doing a downgrade to SLIN first.

Thanks,
Serhad Doken

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From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Michael Graves
Sent: Thursday, June 18, 2009 4:06 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] Wideband (G722) MeetMe

I'm told that Asterisks wideband capability is exclusively based upon 16 khz sampling. Higher sampling rates, like you might find with CELT, are downsampled for mixing at 16 khz.

My guess is that not everyone will be happy with this, especially vendors trumpeting codecs with higher sampling rates. To handle their output will be more CPU intensive.

I'm not an Asterisk insider. I just listen closely when the real insiders speak up ;-)

Michael

--Original Message Text---
From: Doken, Serhad
Date: Thu, 18 Jun 2009 14:15:42 -0700

Thanks Michael. I guess prior to 1.6.2, Asterisk was downgrading streams to SLIN before mixing and then mixed stream got upgraded to WB.

My question is, with this release, is Asterisk converting WB codecs to SLIN16 and mix them that way ? That seems to be the logical way to me just wanted an insider expert to confirm/deny that.

Is this the right list to ask that question/find the right contact before I delve into the code knee deep ?

Serhad Doken

From: asterisk-users-bounces at lists.digium.com [mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Michael Graves
Sent: Thursday, June 18, 2009 6:14 AM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: Re: [asterisk-users] Wideband (G722) MeetMe

--Original Message Text---
From: Doken, Serhad
Date: Wed, 17 Jun 2009 16:07:12 -0700

Hi,

I wanted to follow up on this thread about WB support on the MeetMe bridge that is in 1.6.2. Does it only work for G722 or any WB codec ?

I am working with another 16k WB codec that I can transcode to 722 and vice versa. I was curious if the 1.6.2 MeetMe bridge can also mix 722 with any other WB codec natively(without downscaling).

Thanks,

Serhad Doken

While not an expert in Asterisk internal, it seems unlikely that Asterisk is mixing signals in encoded space. It's most likely converting the stream to slin for mixing then encoding back into whatever is most appropriate for each end-point.

Michael

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Michael Graves
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From: Doken, Serhad
Sent: Wednesday, June 17, 2009 4:07 PM
To: 'asterisk-users at lists.digium.com'
Subject: Re: [asterisk-users] Wideband (G722) MeetMe

Hi,

I wanted to follow up on this thread about WB support on the MeetMe bridge that is in 1.6.2. Does it only work for G722 or any WB codec ?

I am working with another 16k WB codec that I can transcode to 722 and vice versa. I was curious if the 1.6.2 MeetMe bridge can also mix 722 with any other WB codec natively(without downscaling).

Thanks,

Serhad Doken

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Razza wrote:

If so, i've also read that Joshua Colp was/is working on a replacement (conf_bridge?) that works with G722. If this is this still in active development are there any planned timelines? If it's in 1.6.0.6, and i've just missed it or it's been renamed please be nice in your responses! :o)

It was just merged into Asterisk SVN trunk, on its way to becoming part of Asterisk 1.6.2. It's new and still has some limitations, but progress is being made and we welcome additional testing!
-- Kevin P. Fleming Digium, Inc. | Director of Software Technologies 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA skype: kpfleming | jabber: kpfl... at digium.com<mailto:kpfl... at digium.com> Check us out at www.digium.com<http://www.digium.com> & www.asterisk.org<http://www.asterisk.org>

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