Announcement/Voice breaking/distortion in Elastix

Discussion in 'General' started by senthilarasu, Aug 13, 2009.

  1. senthilarasu

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    Hello all,

    I have voice quality (breaking, slow, crackling, distortion) in all asterisk based voice announcement issue using Elastix.

    Asterisk version:
    Asterisk 1.4.25.1 built by root @ rpmbuild32.elastix.palosanto.com on a i686 running Linux on 2009-06-14 11:49:25 UTC

    SIP protocols used. NO other digital/analog or any TDM modules installed in the box. Tested with softclient Xlite & also from mobile phone

    Scenario:1
    When I try to make call out using a2billing, I get the calling card IVR announcement in crackling, breaking voice. But once after I connect to leg B, I have a good quality.
    I made several calls and it is same. once the media path establish between end device, quality is OK. Quality issue only when I any announcement/voice prompt that comes from Elastix PBX.

    So this clearly shows that the issue is internal or A2B.

    Scenario 2:
    To rule out that the issue is not in A2B, I route DDI directly to internal IVR (so no connection to A2B, at all). still same issue.

    Scenario3:
    I copied the same file to desktop (I am running Elastix in VMware) and IVR announcement is clear without any problem.


    So What I guess is the issue should be

    1. CPU/ System Load. (I am using Dell Vostro 200 2.5GHz, Concurrent calls is almost zero, as the box is not in production, 2GB RAM, CPU usage is around 1% ----> so this is ruled out

    2. CODEC issue - configured with ulaw & alaw

    3. Sound files permission (I checked the whole /var/lib/asterisk/sounds folder has executeable permission& owner set to asterisk)

    4. Google & other forum search showed me that non-synch between Hardwareclock & systemclock could cause this issue.

    [root@XXX]# hwclock --show
    Wed 12 Aug 2009 10:33:53 PM GMT -0.144915 seconds
    [root@XXX]# date
    Wed Aug 12 22:33:19 GMT 2009

    I don't see any clue in Asterisk log files..

    Can some experts here can help me to resolve this issue. Let me know any other details required to diagonise this issue/

    I need to fix this issue before I move further...

    YOUR HELP WILL BE MUCH APPRECIATED

    Rgds
    Senthil
     
  2. dicko

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    Is probably the problem.
    Try Elastix on real hardware to verify that your problems go away (to eliminate any network issues). is so , then you need to research the various remedies to fix the kernel timer problems in the version of vmware you are using with the kernel you are using.
     
  3. ramoncio

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    Yes. Someone posted here in the forums a link to a special kernel that avoids choppy sound in vmware, due to incorrect timing.
     
  4. dicko

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    Regards Ramon as ever:

    FWIW

    For VMWare with Elastix 1.5+ I had to build a kernel with dynamic ticks off, a 1k resolution tick and HPET on, the previously available patched VMWare kernels aren't up to date enough for our current release, for other reasons

    (still not happy with my kernel yet though, it's just a work in progress)

    JM2CW

    dicko
     
  5. senthilarasu

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  6. dicko

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