[OpenSIPS-Users] codec manipulation feature

[Brett Nemeroff]

Nice.. That's about what I had in mind.. I'll be looking for more discussion
regarding this. :)-Brett


On Mon, Jun 15, 2009 at 8:21 PM, Bogdan-Andrei Iancu <bogdan at voice-system.ro
> wrote:

> Hi Brett,
>
> Brett Nemeroff wrote:
>
>> my $0.02 here.. I'm not sure if this is what you guys had in mind.. but
>> I've had situations where this would be handy.. It'd need to have some way
>> of identifing the codec (by number?). I'm not sure if the core really has
>> anything that parses the SDP by RFC spec,
>>
> there is an SDP parser in the core :)
>
>> so I'm not sure how you'd do things like "removing g729 codec including
>> the annex=b annotation".
>>
> but not sure if so complex :D (like relation between the SDP fields).
>
>> But imaging that anything is possible:
>>
>>  what we had in mind was to add functions to:
>
> 1) test if a codec is advertised
> 2) remove codecs
> 3) change the priority between the existing codecs
>
>
> Regards,
> bogdan
>
>  I imagine functions:
>> reject_codec: reject a call if a codec matches
>> remove_codec: remove an offered codec
>> codec_present: returns true if codec specified is offered
>>
>> if (reject_codec('ulaw')) {
>> sl_send_reply("488","ULAW Calls not allowed");
>> exit;
>> }
>>
>>
>> if ((codec_present('ULAW')) && codec_present('G729a')) {
>> remove_codec('ULAW');
>> xlog("L_INFO","Removing bad codec: ULAW");
>> }
>>
>> if (!codec_present('G729a')){
>> sl_send_reply("488","Please send G729a calls");
>> }
>>
>>
>> On Mon, Jun 15, 2009 at 3:02 PM, Jeff Pyle <jpyle at fidelityvoice.com<mailto:
>> jpyle at fidelityvoice.com>> wrote:
>>
>>    Hi Bogdan,
>>
>>    It’s been a little while since we talked about this. I was
>>    wondering if there was anything in the works to detect and/or
>>    manipulate the codecs present in an SDP.
>>
>>
>>
>>    - Jeff
>>
>>
>>
>>
>>    On 2/1/09 4:08 AM, "Steve Kurzeja" <steve.kurzeja at gmail.com
>>    <http://steve.kurzeja@gmail.com>> wrote:
>>
>>        This idea is quite standard in SBCs, typically called codec
>>        profiles, where you permit only certain codecs to be passed
>>        through the SBC in an INVITE and all the rest are stripped out.
>>
>>        We use it to get around interop issues with certain codecs.
>>        E.g. we have some end devices/customers that have issues using
>>        g729a so we choose to remove this codec for these specific
>>        endpoints.
>>
>>        The poor man's method to implementing this is just doing
>>        header manipulations in the SDP but it would be nice to be
>>        standardized.
>>
>>        Regards,
>>        Steve
>>
>>
>>        On Fri, Jan 30, 2009 at 2:20 AM, Jeff Pyle
>>        <jpyle at fidelityvoice.com <http://jpyle@fidelityvoice.com>> wrote:
>>
>>            Hi Bogdan,
>>
>>            I'm looking for the ability to selectively remove codec
>>            advertisements from
>>            the SDP. For example, if my customer sends a call to me
>>            for PSTN
>>            termination he may advertise G711 and G729, with G711
>>            preferred. By looking
>>            at the number of existing dialogs I may know that he's
>>            running low on
>>            bandwidth, so I would like to suppress the G711
>>            advertisement ultimately
>>            causing a 200 OK from the carrier with G729.
>>
>>            Generically, in this application we're looking only to
>>            suppress G711 at
>>            certain times.
>>
>>            I understand normally codec selection is done completely
>>            by the gateway
>>            device. However, my gateway devices aren't smart enough to
>>            take bandwidth
>>            utilization into consideration when choosing which codecs
>>            to advertise. I'm
>>            hoping my proxy might be. :)
>>
>>            Does that make sense?
>>
>>
>>
>>            - Jeff
>>
>>
>>
>>            On 1/29/09 5:04 AM, "Bogdan-Andrei Iancu"
>>            <bogdan at voice-system.ro <http://bogdan@voice-system.ro>>
>>
>>            wrote:
>>
>>            > Hi Jeff,
>>            >
>>            > right now there is only available some functionality to
>>            check the codecs
>>            > (to see what codecs are advertised in the SDP)... What
>>            exactly are you
>>            > looking for (like codec ops) ?
>>            >
>>            > Regards,
>>            > Bogdan
>>            >
>>            > Jeff Pyle wrote:
>>            >> Bogdan,
>>            >>
>>            >> Some months back you mentioned an upcoming feature that
>>            would allow
>>            >> Opensips to manipulate the codecs present in the SDP.
>>            Just wondering
>>            >> if there is anything available to test yet. This feature, in
>>            >> combination with dialog contexts, will be of great use
>>            to us to allow
>>            >> us to take a guess at the bandwidth consumption for a
>>            particular
>>            >> customer and force the use of a compressed codec if
>>            necessary.
>>            >>
>>            >>
>>            >> Thanks,
>>            >> Jeff
>>            >
>>
>>
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>>
>>
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>>
>
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