[asterisk-dev] [svn-commits] mmichelson: branch mmichelson/correct_sdp_answer r206276 - /team/mmichelson/c...

[Mark Michelson]

Olle E. Johansson wrote:
> 13 jul 2009 kl. 23.29 skrev SVN commits to the Digium repositories:
> 
>> Author: mmichelson
>> Date: Mon Jul 13 16:29:13 2009
>> New Revision: 206276
>>
>> URL: http://svn.asterisk.org/svn-view/asterisk?view=rev&rev=206276
>> Log:
>> Creating a branch to solve issue 12434.
>>
>> Asterisk currently has a problem where it does not give proper answers
>> for all media streams offered in an SDP. For instance, in the issue
>> mentioned above, the SDP offer contains a media stream for video.  
>> Since
>> video support is disabled, though, Asterisk provides no answer for the
>> video stream offered. Asterisk should have a corresponding m= line
>> in its answer that sets the port to 0.
>>
>> For this branch, I will not be attempting to make any sweeping changes
>> to the SDP parser. I will simply be making sure that if we are going  
>> to
>> answer an SDP, that we have all media offers accounted for in the  
>> answer.
>>
> 
> The hard part is when you get an offer with multiple streams of the  
> same type
> and offers of unknown streams. We need to be able to handle that too,
> but it requires us to more or less store the incoming SDP verbatim.
> 
> This is a bug that has been in Asterisk for ages. If there's a simple  
> fix
> for just handling answering on the known media streams in Asterisk
> - fax, video, audio, text - we should propably look into integrating  
> that fix
> into 1.4 and 1.6.x as bug fixes.
> 
> A more complex fix that handles multiple streams and "unknown"
> media formats is propably something for trunk.
> 
> Thank you for looking into this very old bug.
> 
> /O

These are all excellent points. My goal for this branch, which is based off 1.4, 
is simply to have an answer for all media streams encountered, if we are going 
to answer at all. I won't try to provide answers for any SDP that would have 
been rejected previously, nor am I going to try to handle multiple streams of a 
single type.

Mark Michelson