Re: [Opalvoip-user] Trable with adjisting media formats in OpenSourceMediaStreams

[Robert J. <ro...@vo...>]

Looks like correct behaviour to me, even if different to before. If you set
the media format mask at the manager level to exclude G.711 then G.711 is
excluded for ALL endpoints. That makes perfect sense to me. How can the
system know which endpoints to apply the mask and which not?

 

However, I can see your difficulty, even if you override the
AdjustMediaFormats() functions to control the availability on a per
connection basis, it will still only give the intersection of the media
format sets.

 

To get around I have added an extra parameter to the AdjustMediaFormats() to
help if it is adjusting the media formats for some other connection, that
way you can override it and adjust the formats correctly for your
application.

 

Alternatively you can set the OPAL_OPT_REMOVE_CODEC string option on a
connection basis which I think (at least now) would achieve the same thing.

 

 

Robert Jongbloed

OPAL/OpenH323/PTLib Architect and Co-founder.

 

From: Yuriy Cherniavsky [mailto:yur...@gm...] 
Sent: Wednesday, 28 October 2009 8:01 AM
To: opa...@li...
Subject: [Opalvoip-user] Trable with adjisting media formats in
OpenSourceMediaStreams

 

Hi OPAL community.

 

My use case is H323 -> OPAL -> MyEndPoint.

My EndPoint connections may processing only G711.

>From H323 I wish to receive only for example G729 and G723.1 in
corresponding order.

So two stage transcoding require (G729 -> PCM -> G711).

 

I implement this by SetMediaFormatOrder to [G729, G723.1] and
SetMediaFormatMask to [all except G729, G723.1].

 

All work perfect till commit number 23581 of rjongbloed "Added ability for
connections to get in and adjust media formats during OPenSourceMediaStreams
execution.",

Index: call.cxx

===================================================================

--- call.cxx    (revision 23580)

+++ call.cxx    (revision 23581)

@@ -477,6 +477,8 @@

     order += '@' + mediaType;        // And media of the same type

 

     OpalMediaFormatList sinkMediaFormats =
otherConnection->GetMediaFormats();

+    otherConnection->AdjustMediaFormats(sinkMediaFormats);

+    connection.AdjustMediaFormats(sinkMediaFormats);

     if (preselectedFormat.IsValid() &&
sinkMediaFormats.HasFormat(preselectedFormat))

       sinkMediaFormats = preselectedFormat;

     else

@@ -487,6 +489,8 @@

       sourceMediaFormats = sourceFormat; // Use the source format already
established

     else {

       sourceMediaFormats = connection.GetMediaFormats();

+      otherConnection->AdjustMediaFormats(sourceMediaFormats);

+      connection.AdjustMediaFormats(sourceMediaFormats);

       if (preselectedFormat.IsValid() &&
sourceMediaFormats.HasFormat(preselectedFormat))

         sourceMediaFormats = preselectedFormat;

       else

 

Now I receive this message in log (and no correct media streams are opening
in result):

call.cxx(509)        Call        OpenSourceMediaStreams failed with no
source formats for audio session 1 on
Call[C4b6633511]-EP<voipadapt>[adaptconnection/1]

because default implementation of AdjustMediaFormats gets from OpalManager:

void OpalManager::AdjustMediaFormats(const OpalConnection & /*connection*/,

                                     OpalMediaFormatList & mediaFormats)
const

{

  mediaFormats.Remove(mediaFormatMask);

  mediaFormats.Reorder(mediaFormatOrder);

}

so

      sourceMediaFormats = connection.GetMediaFormats(); << call.cxx:505

return G711 in sourceMediaFormats variable, and after 

      otherConnection->AdjustMediaFormats(sourceMediaFormats);

      connection.AdjustMediaFormats(sourceMediaFormats);

G711 codec removed from sourceMediaFormats variable due to default
implementation of AdjustMediaFormats method.

 

Does something wrong with this commit or something wrong with my logic?

Please explain how I need to implement such behavior, if problem in my
logic.

Or correct this commit, if problem in it.

 

Truly yours, Yuriy.