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";
2- Create a "codec_init_info_t" struct that will have two fields:
"ptime" and a pointer to "ph_media_payload_s*". And the life time of
this struct will be only inside "ph_msession_audio_stream_hardstart"
method.
On both approaches, I was thinking to get the "ptime" field from
"ph_media_payload_s" as the final result.
Any ideias?
Thanks and best regards,
Mauro.
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
--
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 |
|
