[h323plus] Dynamic Bandwidth Management!!

[Simon Horne]

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 at lists.packetizer.com
[mailto:h323plus-bounces at lists.packetizer.com]On Behalf Of Robert Jongbloed
  Sent: Tuesday, January 22, 2008 7:23 AM
  To: h323plus at 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 at lists.packetizer.com
[mailto:h323plus-bounces at lists.packetizer.com] On Behalf Of Paul E. Jones
  Sent: Tuesday, 22 January 2008 1:00 AM
  To: Frank Fischer; h323plus at 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 at 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






--------------------------------------------------------------------------

      From: h323plus-bounces at lists.packetizer.com
[mailto:h323plus-bounces at lists.packetizer.com] On Behalf Of Paul E. Jones
      Sent: Monday, January 21, 2008 2:33 PM
      To: Abhishek Rohilla; h323plus at 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 at 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



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