[Asterisk-Users] filling suppressed silence with chan_oh323

[Siggi Langauf]

On Thu, 12 Jun 2003, Michael Manousos wrote:

> Thanks for your thorough report and test results.
> You are right. The transmission of voice packets after
> silence periods is done with incorrect timestamps,
> causing slight voice drop-outs.
> I 'll see how this can be fixed and let you know.

Cool. Thanks in advance!
And while I'm at it: thanks for writing the driver in the first place!
Let me know if I can do anything to help...

Cheers,
	Siggi


(unchanged fullquote follows...)

> Siggi Langauf wrote:
> > After some more analysis of my "dropped fragment" problem, things look
> > like this:
> >
> > Cisco 7940 phone -- RTP --> chan_oh323 --> Asterisk
> >                                            (running, eg., VoiceMailMain)
> >
> > That RTP connection was negotiated via H.323 on a third machine running
> > Cisco CallManager 3.2, but this part should not be relevant.
> >
> > Connections work fine, with one exception:
> >
> > Whenever there's a break in *'s voice stream (eg. between the "mailbox"
> > and "password" prompts), the 7940 detects horrible jitter and drops a few
> > packets (eg. the whole "password" prompt).
> >
> > Using ethereal, I found that the RTP packets sent by asterisk seem to have
> > bogus timestamps:
> > After the gap, timestamps continue just as if there hasn't been a gap, so
> > timestamp / sequence number always is constant.
> > This should be fine for continuous RTP streams, so I tried disabling
> > silence suppression in oh323.conf. However, * still only sends out packets
> > while it is playing, and not between playback phases.
> > So AFAICT, there are two possible solutions:
> >
> > 1) make chan_oh323 stream continuously, no matter if the current
> >    application does not play audio. IOW: transmit silence instead of no
> >    packets. Is this possible?
> >
> > 2) use better timestamps in streamed packets, ie increase timestamps even
> >    after a period of silence, and not only for each sent packet.
> >    Not sure if that makes the phone happy, though...
> >
> > Any chance to do one of those?
> >
> > Thanks in advance,
> >
> > 	Siggi
> >
> >
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>
>
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