Drop video when dialing outbound trunk

FreePBX Configuration
1

I have a Cisco 8865 phone that I have connected to FreePBX and registered successfully. All the features that I need work, except for one quirk that I’d like to fix. When I place an outbound call to an outbound SIP trunk with the shutter closed, the phone still seems to negotiate video with FreePBX/Asterisk, even though the SIP trunk doesn’t have any video codecs enabled (ulaw only). Consequently, the call drops after 30 seconds if I keep the shutter closed even though it’s only an audio SIP trunk because “Disconnecting channel ‘PJSIP/xxxxxxxx’ for lack of video RTP activity in 32 seconds” If I place a call with the camera shutter open, the call stays online indefinitely on a SIP outbound trunk. I’d like to be able to drop the video connection when placing an outbound sip trunk call.

I’ve looked around at a few different posts and came up with adding the following to extensions_custom.conf, but this doesn’t do it. I also attempted to use Set(“__SIP_CODEC”), but I think that is only for chan_sip, so it didn’t work.

Am I going at this the right way or do I need to explore something else? Disabling the video codecs on the phone’s extension configuration does work, but then I lose video calling between extensions, which is something I want to keep.

[macro-dialout-trunk-predial-hook]
exten => s,1,NoOp(Run Dialout Trunk Predial Hook)
exten => s,n,Set(PJSIP_MEDIA_OFFER(video)=!all)
exten => s,n,Set(PJSIP_MEDIA_OFFER(audio)=ulaw)
exten => s,n,NoOp(Video Offer: ${PJSIP_MEDIA_OFFER(video)})
exten => s,n,NoOp(Audio Offer: ${PJSIP_MEDIA_OFFER(audio)})
exten => s,n,Return()

Edit: FreePBX 17.0.19.27 is the version I’m running.

2

Setting PJSIP_MEDIA_OFFER affects the outbound channel. You need a way to affect the SDP answer (not offer) from Asterisk back to your phone depending on the dialed number, which I don’t think you can do.

A hacky (bad) idea would be to set up two different extensions on the phone, one with the video codec enabled and one without, and use the video-enabled extension when you want video and the non-video extension for PSTN calls.

(I put bad ideas into the forum so that someone else will say how bad it is and rise to the challenge of providing a better solution.)

1 Like
3

Love this haha. I might have to do the second extension idea. My other bad idea is to put a sticker on the phone that says “leave shutter open when placing out of office call”

I’ll see what I can find on the SDP offer info, thanks for that direction. I worked with Asterisk about 10-15 years ago, but haven’t picked it back up until recently, and realize I’ve forgotten a lot of it.

If anyone else has any thoughts on this, please chime in!