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Voice Coder Mystery

Viewing 5 posts - 1 through 5 (of 5 total)
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  • #20868
    R&D Guy
    Guest

    Anyone know why G.723.1 uses more bandwidth than G.729?

    I’ve observed this using Multitech VoIP equipment

    G.723.1 uses up to ~ 2600Bytes/s
    G.729 uses up to ~ 2050Bytes/s

    #20869
    Ageffner
    Guest

    That is peculiar alright.

    I only have two reccomendations.

    1. Takl to Multitech about it, to see if there is a configuration error.

    2. Check out this link: http://www.d2tech.com/vp_alogrit.html

    Which is for the “VP Open Algorithms Libray”, and discusses both Codecs more in detail.

    Are you sure you have header compression set up the same for both, and that you are only having one conversation occur when G.723.1 Codec is on?

    #20870
    Silvio M.
    Guest

    Guys,

    Maybe you are using a different latency.
    Example: If you to use in G723.1 a latency of 30mileseconds you will to use about 16Kbps, but if you to use G729 with a latency of 90mileseconds you will to use about 12Kbps.
    On the other hand if you to use G729 with a latency of 20mileseconds you will to use 24Kbps.
    Maybe in your case you need to adjust the latency to get a good compression.

    Good lock,

    Silvio.

    #20871
    Tom Howard
    Guest

    Silvio,

    Although I agree with your comments, I don’t think the term ‘latency’ is the correct one to use.

    The times you mention are the intervals between packets being sent. That’s not the same as latency, although because of buffering, it is related to latency.

    Latency is the delay introduced by elements in the system (including the CODEC).

    Cheers,
    Tom.

    #20872
    R
    Guest

    Its encoding/decoding delay. Thats what most folks call it. BTW…723.1 uses 33ms packetization period…on the average.

Viewing 5 posts - 1 through 5 (of 5 total)
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