Hi
I maybe wrong but I remember this happening sometimes during codec
renegociation (early media like ring tone negociated by a server, and then
media is negociated with the endpoint using another codec).Jerome


2009/7/30 Vadim Lebedev <[email protected]>

> Hi Mauro
>
> Le 29 juil. 09 à 20:01, Mauro Sergio Ferreira Brasil a écrit :
>
>  Hello there!
>
> I was checking method "ph_media_retrieve_decoded_frame" in order to make
> this final adjustment, and I've got stuck on some considerable blocks of
> code intended to handle a condition where the size of RTP packet received
> from the other part is bigger than expected.
> This is indicated by variable "needreformat".
>
> Is this intended to handle situations where the other part of conversation
> don't respect the negotiated packetization ?
> For example, we indicated preferable packetization through "ptime:20"
> attribute, but the other part keeps sending RTP packets with a bigger frame
> size than expected.
>
> Is for this only reason that these code are used, or am I missing some
> other situation that will demand such "reformatation" ?
>
>
> Yes, it is the only reason...
>
>
>
> Thanks and best regards,
> Mauro.
>
>
>
>
> jerome wagner escreveu:
>
> Mauro, I would follow Vadim on this one.
>
>  There are 2 cases that should be checked :
>   - 1/ really be careful about Linux and MacOSX sound drivers. I agree
> windows drivers always give you the "standard" framesizes you ask but this
> is not the case for Linux or MacOSX
>   - 2/ pay attention to the far-end media mixing during 3-way conference.
> Payloads may arrive on different end points with different framesizes.
> mixing must occur at a shared framesize.
>
>  The current phapi approach is optimized in many cases I think (less
> intermediary buffers = less memory usage) and I think that a dynamic graph
> construction 'a la gstreamer' would be a + :
>  * no buffers when they are not needed (and for embedded targets they are
> more than often are not needed)
>  * buffers for some scenarios
>
>  So a step by step approach could be to add an entity with a
> meta-description of the graph inside phapi to known which graph elements are
> activated and which are not, with what parameters. I don't know about the
> mediastreamer (ortp side project) integration that Vadim was talking about
> recently so I can't really give you more help on this one.
>
>  Hope this helps,
> Jerome
>
>
>  Jerome
>
>
>
> 2009/7/28 Vadim Lebedev <[email protected]>
>
>>  IMO this is the correct way...
>>
>> Thanks
>> Vadim
>> Mauro Sergio Ferreira Brasil wrote:
>>
>> Hi Jerome!
>>
>> I've asked information about how common is that condition because I had no
>> problem here initializing the audio devices of the same soundcard with
>> different framesizes.
>> I've made lots of test calls using my onboard soundcard on Windows with
>> some variety of framesize scenarios, like: 40ms on TX and 20ms on RX; 30ms
>> on both paths (iLBC's "mode" parameter config), etc.
>>
>> Now, considering that I can't rely on anything, I suppose the best choice
>> is to get back the audio devices initialization blocked (i.e. hardcoded) to
>> work with the framesize resulting of 20ms packetization for both paths.
>> This will avoid lots of changes and the inevitable demanded tests.
>>
>> We initialize incoming and outcoming audio paths to work always with
>> framesize of 160 shorts (or 320 if we work at 16 KHz) - that is the way it
>> used to work before the patch I've sent, and create buffer adaption routines
>> to both paths oh "phmedia-audio.c" in order to process the incoming and
>> outgoing data accordingly.
>>
>> What do you think ?
>>
>> Thanks and best regards,
>> Mauro.
>>
>>
> --
>    *At.,
>    *  <CMMI_2.jpg>   *Technology and Quality on Information*  Mauro Sérgio
> Ferreira Brasil  Coordenador de Projetos e Analista de Sistemas  +
> [email protected] <@tqi.com.br>  :  www.tqi.com.br  ( + 55
> (34)3291-1700  ( + 55 (34)9971-2572
>
>
>
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