Re: re: G.729 Codec Jitter Issues In OPAL

Hi manderson,

I have found that G.729 in OPAL is trying to work with 10 ms frames,
which causes a lot of overhead. I adjusted OPAL's default in my code
by adding a specialized version of GetOptimalDataFrameSize to
Opal_G729_PCM and Opal_PCM_G729 classes like so:

PINDEX Opal_G729_PCM::GetOptimalDataFrameSize(BOOL input) const
{
  return (input ? inputBytesPerFrame : outputBytesPerFrame) * 2 ;
}

PINDEX Opal_PCM_G729::GetOptimalDataFrameSize(BOOL input) const
{
  return (input ? inputBytesPerFrame : outputBytesPerFrame) * 2 ;
}

The *2 sets frame size used by patch to 20 ms, which is more
reasonable.

Saturday, February 26, 2005, 1:53:01 AM, you wrote:

mtc> I am trying to transition from OpenH323 to OPAL and have just enabled the
mtc> G.729 codec in OPAL.

mtc> Upon testing calls using the G.729 codec against a few different networks
mtc> have found that the call quality has a lot of fast breaks of silence.  The
mtc> measured packet loss and delay on the end to end Internet connection is
mtc> fairly low so my guess is that the sound buffer size may need to be
mtc> increased and/or there is a subtle bug somewhere.   The problem did not
mtc> occur when the G.711 codec was used.

mtc> What is the simplest way to increase the sound buffer size in OPAL when the
mtc> G.729 is used? 


// ted  http://www.microtronixsystems.com

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