Title: TQI - Technology and Quality on Information
Vadim,

Thanks.
It was great to work on it.

About your comments, please forgive my lack of comprehension of SDP protocol and of Qutecom libraries, but I would like to understant it completely.

I've just kept the payload and used it on the loop to avoid the assignment of "fmtp" attribute to the wrong format/codec.
What you are telling me is that it won't happen because it will exist only one payload media at a time ?

Thanks and best regards!
Mauro.



Vadim Lebedev escreveu:
Mauoro

I only took a quick look at it,  and the only suggestion i have
is that we really don't need to copy the payload number from fmtp string,
we need only copy what follows it.
so the test confirming presence of 111 in it is actually  not needed.

Othewise - congratulations it ois GREAT work.


I'll try to integrate your patches into qutecom tomorrow and will give you more feeback


Thanks
Vadim



Mauro Sérgio Ferreira Brasil wrote:
Hi Vadim!

Patch worked perfectly on my 2.1 changed version of Openwengo source codes.

The changesets follow attached.
I've made them after paste the changes on current version 2.2 of Qutecom source codes.

As I've said before, they need to be validated considering that the version 2.2 codes with these patches were not even compiled here.
Could you please give me a reply on that ?

Thanks and best regards,
Mauro.



Mauro Sérgio Ferreira Brasil escreveu:
Thanks a lot for the quicky response Vadim, and sorry by the too frequent questions.

I agree with you to proceed with option 1.

Best regards,
Mauro.



Vadim Lebedev escreveu:
Mauro,

I agree  that option 2 is better, however from practical standpoint
option 1 is quicker to implement and less invasive.

So i would suggest option 1 for the moment, however this is your decision


Thanks
Vadim
Mauro Sérgio Ferreira Brasil wrote:
Hi Vadim!

I have a new issue here.

On "ph_msession_audio_stream_hardstart" method, the field "ptime" of "phastream_t" stream struct is initialized before call to "open_audio_device".

Now that the final value of "ptime" field will be known just after "encoder_init()", invocation, I need to choose one of two approaches:

1- Get the "encoder_init()" and "decoder_init()" blocks up and before "open_audio_device" invokation, taking care to execute the "cleanup" method whether any error occurs;

2- Create a separated field on "phcodec_t" to a method responsible to calculate the final frame size (20, 30, 40ms, etc) that will be executed on beggining of "ph_msession_audio_stream_hardstart" method, using the "int" result on "open_audio_device" and encoder/decoder initialization methods;
I prefer this approuch for the following reasons: 1- It will reduce the calculation of final "ptime" to just one point (now it is made on encoder and decoder initialization); 2- We can use the result computed once on every points inside this method; 3- We could initialize the "phcodec_t" respective field with iLBC implementation, and left as NULL for the others codecs that I don't know whether have especific packetization rules through "fmtp" attribute;

Any ideas, sugestions ?

Thanks and best regards,
Mauro.




Vadim Lebedev escreveu:
Hi Mauro,

Le 19 nov. 08 à 21:11, Mauro Sérgio Ferreira Brasil a écrit :

Hi Vadim,

I've noticed just one more issue.

We are passing "ph_media_payload_s" to the "encoder_init" so it can decide the packetization, but we are not considering the global "ptime" value that comes on global media atribute "ptime: 20".
The codec need to know this value as well, because it will be used whether it's negotiated and no mode is informed.

I think we have two choices:

1- Replicate the "ptime" value to "ptime" field of "ph_media_payload_s" before it's passed to "encoder_init";


YES

Thanks
Vadim


Vadim Lebedev escreveu:

YES, YES, YES

Thanks
Vadim
Mauro Sérgio Ferreira Brasil wrote:
Vadim,

I think I understood now why you've suggested to store the "mode" info present on new "fmtp" field of the "ph_media_payload_s" on field "ptime" by the "encoder_init" of the associated codec.

This way the steps below could be considerable reduced with:

Step 3: the value will be stored on field "ptime" (and can be stored on "mode" too for accuracy);

Step 4: We validate the "ptime" of the specific payload. If the value is different from "0", this value will be assigned to field "ptime" of "phastream_t". If it's equal to "0", we use the global "ptime" present on "ph_mstream_params_t";

Step 5: Is not necessary. Because we will deal with only "ptime" field on "phastream_t".

I think this is really a better and simpler approach.

It was that you were thinking about ?

Best regards,
Mauro




Mauro Sérgio Ferreira Brasil escreveu:
Hi Vadim,

Let's try to close all the steps of the entire procedure:

1- "fmtp" media attributes will be stored on "eXosip_event" structure during execution of method "eXosip_event_add_sdp_info";
For now I'm saving only the value strings of the attribute pair, like: "111 mode=30". Do you want to save the complete attribute string, like "fmtp: 111 mode=30"?

2- The scope of "eXosip_event" structure on media activation ends on method "ph_call_media_start". So, in it we initialize the "fmtp" field of each "ph_media_payload_s" structure of "ph_msession_s";
Just one question here. Is "fmtp" atribute unique for a especific format/codec ? If so, everything is fine.

3- On "ph_msession_audio_stream_hardstart" method we will inform the "ph_media_payload_s*" as a parameter to the "encoder_init" method which, on the case of iLBC codec, will update the "mode" field with the respective mode collected from the "fmtp" field;
Any problems with that Vadim ? You sugested to put this value on "ptime" field, but I think it would be better to store the mode info on the respective "mode" field. Now the decision is yours :-)

4- Still on this method, we will assign the "ptime" field of the "phastream_t" struct with the global value of "ptime" from "ph_mstream_params_t", and a new field "mode" with the value of the especific payload "mode" value given by "sp->ipayloads[0].mode";
Still ok until here ?

5- On "ph_astream_decoded_framesize_get" method, we will priorize the "mode" field value to the calculation of fame size, followed by the "ptime" field, both from "phastream_t". The code will look like:

    if (stream->mode)
    {
        // Mode changes the final frame sime the same way "ptime" does. Modify the framesize to manage the informed mode.
        framesize = framesize * stream->mode/ 20;
    }
    else if (stream->ptime)
    {
        // Default ptime is 20ms, modify the framesize to manage the new ptime.
        framesize = framesize * stream->ptime / 20;
    }

I think that's it.
Please let me know whether I forgot something.

Thanks,
Mauro.



Vadim Lebedev escreveu:
Hi Mauro,

see the comments inline

Mauro Sérgio Ferreira Brasil wrote:
Hi Vadim!

Thanks for the reply.
In fact I need some help of more experienced guys like you to define the points I haven't still decided.

They were detailed on email below, and I'll list them shortly here:

1- Are you fine with my choice to invoke method "eXosip_get_sdp_media_format_info" from method "eXosip_event_add_sdp_info" instead of calling it from method "eXosip_get_sdp_media_info" ?

OK
2- Should I create a field on struct "ph_mstream_param_s" (using a global approach, like on ptime), or should I use the "mode" field already present on elements of "ipayloads" field ? I'm not completely sure how to handle this situation by now, because I don't know all scenarios (like I've said on prior email, always I have just one "ph_mstream_param_s" on my session (of 4 maximum), that have configured just one "ph_media_payload_s" on "ipayloads" field (of 16 maximum).
Considering this scenario, maybe a global "mode" field on "ph_mstream_param_s" struct will provide a cleaner solution. But whether we do need to consider another streams, we will have to map the "mode" on the respective "ph_media_payload_s" field.

I think it would be better to implement it per payload.
I was thinking to add a const 'char *fmtp'  and int ptime ph_media_payload_s.
if we could pass ph_media_payload to the codec intializer it could fill ptime based on fmtp. What do you think?

3- During the calculation of allocation blocks using "ph_astream_decoded_framesize_get", I'm thinking to change the algorithm just to validate first the existence of a "mode" attribute that will have priority agains "ptime".
This is the only change this method will probably have.

In line with my previous comment,  the ph_astream_decoded_framesize_get will use ptime
from ph_media_payload_s  structure if nonzero
For the sake of simplicity I've omitted changes pointed like the creation of "format_modifiers" on "eXosip_event" struct, and the names given to new methods (like "eXosip_get_sdp_media_format_info"), considering that you have agreed with them.

Please confirm that to me too.


Ok for me
This approach only makes me unconfortable considering that "mode" attribute value is dependent of the codec or format. So maybe we should in fact extend the "phcodec_t" struct to accept a new field that is a method responsible to return the frame size considering a parameter of type "ph_media_payload_s".
If we choose to follow this idea, maybe we should remove "ptime" field of "ph_mstream_params_s" struct and update its value on "ptime" field of each valid "ph_media_payload_s" element.

This is valid approach too, i think that what i'm proposing (setting ph_media_payload_s.ptime in the codec initializer based on fmtp) will require less modification to the code,  but otherwise your approach is equivalent so it is your call.


Thanks
Vadim



--
At.,                                                                                                                               
 
Technology and Quality on Information
Mauro Sérgio Ferreira Brasil
Coordenador de Projetos e Analista de Sistemas
+ [EMAIL PROTECTED]
: www.tqi.com.br
( + 55 (34)3291-1700
( + 55 (34)9971-2572


--
TQI - Technology and Quality on Information
At.,                                                                                                                               
 
Technology and Quality on Information
Mauro Sérgio Ferreira Brasil
Coordenador de Projetos e Analista de Sistemas
+ [EMAIL PROTECTED]
: www.tqi.com.br
( + 55 (34)3291-1700
( + 55 (34)9971-2572
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