Codec bandwidth issue

Discussion in 'General' started by feelingless, Oct 26, 2010.

  1. feelingless

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    Hi all,

    I'm using Elastix 1.5.2 with G.711 standard with u-law, a-law. As I known, this takes about 64kbps bitstream or more. Now, I want to find others for replacing to reduce bandwidth (16 or 32) for calls but still hear good voice. However, I have no experience about this, so I would like to have your help to decide which kind of codec I should use for my server.

    Thanks,
    --F
     
  2. Lee Sharp

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  3. tsku

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    go and buy g729 at USD10 per channel and bandwidth consume only 8kbps instead of 64kbps for A/Ulaw.
     
  4. feelingless

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    Hi all,

    Thanks for your help.

    I would like to know why we choose G729 but not G726, G723, G728, GSM, or iLIB? As I known in Elastix without tears, G723 just takes about 5-6kbps, others are from 16 - 32kbps. Is there any technical description that can give us a brief comparison among them then decide which one we should choose?

    Thanks again,
    --F
     
  5. Lee Sharp

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    g723 works in passthrough (which is useless in my opinion) but it also requires a license.
    g726 in only 32k, so not a huge savings. It also was buggy early on.
    gsm is fine the old way, but a lot of people (read phones) use the "new" gsm which is patent encumbered.
    ilbc is open and free, but not widely used.

    ulaw and alaw, however, are the standard. They are what T1 circuits speak. Everything supports it. And sound quality is good. Everything needs to support g729 so that we always have a common fallback.

    http://www.voip-info.org/wiki/view/Asterisk+codecs
     

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