[asterisk-dev] [Code Review] 3365: res_pjsip_session: decline SDP offers with no audio streams

[Matt Jordan]

> On March 17, 2014, 2:12 a.m., Olle E Johansson wrote:
> > That Asterisk *needs* audio was not true before. If it is, then we've broken things. When I worked with T.140 realtime text we made it possible to place calls with video and text, no audio. It took a while, but it did work in a few releases. Have no test software at this moment, but if that statement is true we have a problem.

Well, real-time text isn't really applicable here, as that support hasn't been added to the PJSIP channel driver.

Video only is something that is a bit ... odd ... in Asterisk. I'm sure it worked better at one point in time, but it's probably been a long time since it worked correctly - and consistently - in all applications. I have a feeling that the translation core is most likely to blame for something in there.

This patch is really due to a lot of tests I'm writing to support Josh's format work; that may end up precluding the need for this in the first place. I'm happy to pull it for now - we'll see if we can't find what is wonky.


- Matt


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On March 16, 2014, 3:36 p.m., Matt Jordan wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> https://reviewboard.asterisk.org/r/3365/
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> 
> (Updated March 16, 2014, 3:36 p.m.)
> 
> 
> Review request for Asterisk Developers and Joshua Colp.
> 
> 
> Repository: Asterisk
> 
> 
> Description
> -------
> 
> In a perfect world, an Asterisk channel would care very little (if at all) about the media streams that happened to be related to it. It would merrily exist as a path of communication between some endpoint and Asterisk, and the data (which may or may not be media at all!) that flowed (like a stream!) between the endpoint and Asterisk would be a completely separate concept. Alas, such is not the world we exist in. Asterisk *needs* audio. As frames. At a nice periodic rate, please. Strange things happen when it doesn't get it.
> 
> Today, the res_pjsip stack will do some funky things if you give it an offer with no media. There will be a slew of warnings, some compatibility errors, strange transcoding attempts, and finally you may get an Answer to the Offer that contains an audio codec in a video media stream (probably ulaw) - just because Asterisk *really* wants audio. (Can you please send some with this video?)
> 
> This is clearly not right. This patch makes it so that res_pjsip_session looks to see if we have an audio stream (in validate_sdp) and, if not, it declines the offer.
> 
> I offer this patch in the hopes that it will some day be removed...
> 
> 
> Diffs
> -----
> 
>   /branches/12/res/res_pjsip_session.c 410554 
>   /branches/12/res/res_pjsip_sdp_rtp.c 410554 
>   /branches/12/include/asterisk/res_pjsip_session.h 410554 
> 
> Diff: https://reviewboard.asterisk.org/r/3365/diff/
> 
> 
> Testing
> -------
> 
> Tests are ongoing. A test has been written that offers only a single video stream. Prior to this patch; hilarity. With this patch, Asterisk rejects the offer with a 488.
> 
> 
> Thanks,
> 
> Matt Jordan
> 
>

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