To all

G722.2 (AMR-WB) implementation is available from VoiceAge (for windows) http://www.voiceage.com/openinit_amrwb.php

If anyone has the time to do the audio plugin, the capability exchange is defined in H.245 Annex R

This is on my to-do lists but contributions are most welcome

Simon -----Original Message----- From: h323plus-bounces@lists.packetizer.com [mailto:h323plus-bounces@lists.packetizer.com]On Behalf Of Robert Jongbloed Sent: Tuesday, January 22, 2008 7:23 AM To: h323plus@lists.packetizer.com Subject: Re: [h323plus] Dynamic Bandwidth Management!!

The other possibility is that he is talking about "in call" bandwidth management, specifically the H.245 FlowControlCommand/FlowControlIndication messages which can be used to control the bandwidth of a specific codec. For audio it is not hugely useful unless you have something like GSM-AMR or G.722.2 (aka GSM-AMR wideband) which have a few bit rate options, but it can be really useful for video as most codecs have a wide range of bit rates.

Both H323plus and OPAL have "bits and pieces" of support for this, but no one has ever really looked closely at it to give it a really good debug. At least no one out there that has admitted to it! L

As another throw away comment: the rise in available bit rate will hopefully make wide band codecs such as Speex-wb and G.722.2 more popular. I 've used them in other environments and the quality is noticeably better, and as voice quality is one of the biggest complaints people have with VoIP, it can only help!

Robert Jongbloed

OPAL/OpenH323 Architect and Co-founder.

From: h323plus-bounces@lists.packetizer.com [mailto:h323plus-bounces@lists.packetizer.com] On Behalf Of Paul E. Jones Sent: Tuesday, 22 January 2008 1:00 AM To: Frank Fischer; h323plus@lists.packetizer.com Subject: Re: [h323plus] Dynamic Bandwidth Management!!

Frank,

Ah, OK. That makes sense.

From an H.323 perspective, this kind of thing is almost doable, but no remote device would be obliged to make adjustments. One could send a Request Mode message and the receiver could politely refuse. (Likewise, a SIP device could refuse an offer to propose changes to established media flows.) The other issue is knowing whether or not bandwidth needs to be adjusted or can be adjusted. One might say that bandwidth could increase, because there is no observed packet loss. But, perhaps an increase in bandwidth might then disrupt some other service (e.g., other voice calls in progress). So, then perhaps the bandwidth might be decreased to compensate. This then leads one in a vicious cycle of bandwidth adjustments up and down.

And, as you rightfully point out, available bandwidth is constantly rising and it will continue, since people want to utilize services that require more bandwidth and want to use even more services simultaneously. The 80Kbps voice call is really very little compared to the Gbps of bandwidth most broadband customers have today. Still, there are bandwidth-constrained locations, but the best recommendation I could make is to simply select a lower bit-rate codec and use that. Skype, for example, always uses G.729 for calls to PSTN gateways and the sound quality seems very good to me.

Paul

----- Original Message -----

From: Frank Fischer

To: h323plus@lists.packetizer.com

Sent: Monday, January 21, 2008 8:42 AM

Subject: Re: [h323plus] Dynamic Bandwidth Management!!

Hi

i think he means the abillity to dynamically change the codec during transmission to follow any changes in available bandwith. I.e. when starting with g.711 and the available bandwith drops to 80kbits then i.e. g.729 could be negotiated on the fly.

Actually a very nice feature but probably not very easy to implement and more important, getting less and lesser important since bandwiths are constently increasing almost all over the world....

Frank

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From: h323plus-bounces@lists.packetizer.com [mailto:h323plus-bounces@lists.packetizer.com] On Behalf Of Paul E. Jones Sent: Monday, January 21, 2008 2:33 PM To: Abhishek Rohilla; h323plus@lists.packetizer.com Subject: Re: [h323plus] Dynamic Bandwidth Management!!

Abhishek,

H.323 Plus aside, what do you mean by "dynamic bandwidth management"?

Paul

----- Original Message -----

From: Abhishek Rohilla

To: h323plus@lists.packetizer.com

Sent: Monday, January 21, 2008 4:44 AM

Subject: [h323plus] Dynamic Bandwidth Management!!

Hi

Someone please help me with this. I wanted to know does H323+ does dynamic bandwidth management and mange the codec bit rate accordingly?

How is it done.?? Where can I find the code in RTP files in H323+ where bandwidth info is calculated?

Thanks