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Re: [reSIProcate] rtp ringing


Thanks to all for your input. I'll be happy to post my final solution once
I've explored all options. Thanks again,

David

-----Original Message-----
From: resiprocate-devel-bounces@xxxxxxxxxxxxxxx
[mailto:resiprocate-devel-bounces@xxxxxxxxxxxxxxx] On Behalf Of Robert
Sparks
Sent: Tuesday, November 20, 2007 6:03 PM
To: John McBride
Cc: resiprocate-devel@xxxxxxxxxxxxxxx
Subject: Re: [reSIProcate] rtp ringing

One other caveat while you're exploring this idea.

If you send your ringing from one place (ip address+port) and then  
the media from
the other phone from another (directly from the phone), you could run  
into a problem
with some endpoints that "latch" onto the source of the first media  
packet that they receive
in an attempt to deal with multiple streams coming in as a result of  
a forked invite.

Probably not an issue for you since you said you've built an SBC, but  
I wanted to make
sure you knew it was there.

RjS

On Nov 20, 2007, at 5:01 PM, John McBride wrote:

> For the G711 ring tone - you can alter the frequencies slightly to
> make the difference 100Hz,
> e.g. 445Hz and 345Hz - which will give 100Hz separation and will
> equate to an integer number
> of 8kHz samples. From memory in the UK the frequency tolerance  
> allowed is 5%.
>
> I have done this in the past and it has worked well.
>
> John
>
>
> On 21/11/2007, Adam Roach <adam@xxxxxxxxxxx> wrote:
>> For what you describe, a full RTP stack would be overkill. You can
>> probably get by just sending your packets with an appropriately  
>> encoded
>> RTP header every 20 ms. You'll also need to listen for incoming RTP
>> packets and discard them. (Ideally, you'd calculate statistics  
>> based on
>> these packets and generate proper RTCP; however, in practice, things
>> will pretty much work just fine if you don't).
>>
>> Also: while what you're proposing will work _mostly_ fine for codecs
>> that don't rely on prior frames for encoding (like G.711), you are  
>> very
>> likely to run into difficulty coming up with a single G.729 or G.723
>> packet to represent "ringing." Even with G.711, you'll run into  
>> problems
>> because the standard North-American 350+440 ringback tone doesn't  
>> repeat
>> neatly on 20 ms boundaries.
>>
>> You might try sending an RFC4733 representation of ringback (e.g., if
>> you're targeting the US market: modulation = 0, volume = -6 dBm0,
>> frequency = 350, frequency = 440, duration = 2 seconds; sent every 6
>> seconds or so). Support for this approach may be more limited, so  
>> make
>> sure you test it against all your target devices.
>>
>> /a
>>
>> On 11/20/07 10:37 AM, David Thompson wrote:
>>>
>>> Quick question if anyone has an idea for me:
>>>
>>> I have built an sbc using the reciprocate stack. (THANK YOU to  
>>> all who
>>> have worked on this stack)
>>>
>>> I want to provide my own "ringing" early media rtp for comfort
>>> reasons. I know reciprocate does not offer an RTP stack but I was
>>> wondering if someone could point me in the right direction on  
>>> where I
>>> could look.
>>>
>>> Basically I would already have the ringing file encoded in g729,  
>>> g723,
>>> g711 and would simply want to issue a 180 early media from the sip
>>> stack then start transmitting the rtp in the proper codec. Once the
>>> call completed I would then let the media pass from end point to
>>> endpoint directly.
>>>
>>> Any thoughts would be appreciated..
>>>
>>> David
>>>
>>> -------------------------------------------------------------------- 
>>> ----
>>>
>>> _______________________________________________
>>> resiprocate-devel mailing list
>>> resiprocate-devel@xxxxxxxxxxxxxxx
>>> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel
>>
>> _______________________________________________
>> resiprocate-devel mailing list
>> resiprocate-devel@xxxxxxxxxxxxxxx
>> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel
>>
>
>
> -- 
> John McBride
> Mobile: +61 430 062 005
> _______________________________________________
> resiprocate-devel mailing list
> resiprocate-devel@xxxxxxxxxxxxxxx
> https://list.resiprocate.org/mailman/listinfo/resiprocate-devel

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