G729a and G729 interoperability

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I am wondering how the differences between G729, G729a, and G729b
effect call bridging and server interoperability. For example, can
one server use the G729 code with another server that uses the G729A

Also, which version is Asterisk set up to use?


One thought on - G729a and G729 interoperability

  • There is no compatibility issue between basic G.729 and G.729A. That is
    why they use the same SDP code. In practice it is rare to see a G.729
    codec in real world use. They are almost all G.729A. G.729 sounds
    better, but G.729A uses half the CPU power. Cheaper normally wins over
    better in the real world.

    G.729 annex B is an add on, providing VAD features. It may be used with
    G.729 or G.729A. A separate entry in the SDP says whether this option is