High quality voip

Discussion in 'VOIP' started by Alexis de Goriainoff, Nov 18, 2003.

  1. Hello,

    Does anyone know if there are any means of doing high quality voip.
    By high quality I mean sound quality that would be higher than traditional
    phone between on net clients.

    In theory it should be possible: if we use a voice stream compressed to
    64kb/s using mp3 for example, we could have a very high quality end to end
    communication for the same bandwidth as G711.

    The question is: does any client support this kind of "high quality"
    algorithm: softphone, Ip phones, PBX, pstn gw... ?

    It would be a good way to promote voip: the main argument would not be only
    price but sound quality.
    Alexis de Goriainoff, Nov 18, 2003
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  2. Is MP3 a high-quality sound codec?
    root/administrator, Nov 18, 2003
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  3. mp3 is a codec that can produce sound with high bit rate.
    Alexis de Goriainoff, Nov 20, 2003
  4. What will be the compression ratio of an MP3 file when set with a high-bit
    rate to achieve a high-quality voice as mentioned in the OP' post? Will the
    MP3 file become larger?
    root/administrator, Nov 20, 2003
  5. Alexis de Goriainoff

    kubel Guest

    remember that traditional phone only use 300-3400 Hz of bandwidth
    so does voip codecs
    g711 codec (64kbit/s) causes no loss of quality
    it's a no-compression codec

    kubel, Nov 20, 2003
  6. Alexis de Goriainoff

    Hank Karl Guest

    Look into G722, which has a 7 kHz input audio range and compresses
    speech to 64Kb/s. There are proprietary codecs that have a 7kHz input
    and compress speech to 16Kb/s.

    Be aware that MP3 is an audio coding scheme, while speech codecs like
    G.729 are speech coding schemes. The difference is that MP3 models
    what the ear can hear, and speech codecs model what the human vocal
    tract can produce. In general, speech codecs will sound good for
    speech but not for music--we can hear a piano, but can't sound like
    Many videoconferencing devices support G.722.
    Hank Karl, Nov 20, 2003
  7. Alexis de Goriainoff

    Hank Karl Guest

    IIRC, uLaw on TDM has a 4.4 MOS score. G.711 with 10 mSec packets
    and no packet loss has a 4.2 MOS score. The best MOS score is 5.0, so
    G.711 does have some loss of quality.

    Also, the codec is only one factor in determining the quality of a
    call. Delay and packet loss are two of the many other factors. See
    www.voiptroubleshooter.com for more information on VoIP quality.
    Hank Karl, Nov 20, 2003

  8. Check out Speex (which is free) or the codecs from Global IP Sound
    (which are not). Some softphones have Speex in them. I believe
    Skype uses the Global IP Sound codecs.
    Brad Templeton, Nov 22, 2003
  9. Alexis de Goriainoff

    shope Guest

    I think that some broadcasters use G.722 or better for FM quality sound for
    outside broadcast over ISDN - e.g. concerts, sports and so on.

    Maybe you need to ask about something that traditionally has better sound
    quality - try an audio group?
    shope, Nov 24, 2003
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