Hello to everyone, we have a Kamailio 5.5 + RTPEngine deployment. Some devices will send an invite with both audio and video in the offer and we are trying to disable the video portion of the invite by either setting the video port to 0 or by setting a=inactive in the video portion of the SDP packet. We know that sdpops has a function that would be able to remove the video portion but it violates standards so we can't use it. We need to disable the video in the SDP offers because one of the pstn providers we are using doesn't accept invites that contain a video offer. I've spent days searching but I can't find an obvious way of achieving this. We were originally doing it with textops but we've been having some issues where the sdp wouldn't be modified correctly in reinvites after the original call is in place so we're looking for alternatives. Can someone please help us? Thanks in advance Simone de Blasiis
Hello,
I did not look in the RFC regarding the removing the video line in questions. You are probably referring to the sdp_remove_media() function.
Do you expect problems when you are doing this? A quick web search found a similar suggestion also e.g. for Cisco router and others.
Another option would be to just return a 415 on the proxy level, by also adding the supported types to the Accept header, like this: Accept: audio/*
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.comhttps://gilawa.com/
From: sr-users sr-users-bounces@lists.kamailio.org On Behalf Of Simone de Blasiis Sent: Friday, April 22, 2022 4:32 PM To: sr-users@lists.kamailio.org Subject: [SR-Users] How to disable video in invite with both audio and video
Hello to everyone, we have a Kamailio 5.5 + RTPEngine deployment. Some devices will send an invite with both audio and video in the offer and we are trying to disable the video portion of the invite by either setting the video port to 0 or by setting a=inactive in the video portion of the SDP packet. We know that sdpops has a function that would be able to remove the video portion but it violates standards so we can't use it. We need to disable the video in the SDP offers because one of the pstn providers we are using doesn't accept invites that contain a video offer. I've spent days searching but I can't find an obvious way of achieving this. We were originally doing it with textops but we've been having some issues where the sdp wouldn't be modified correctly in reinvites after the original call is in place so we're looking for alternatives. Can someone please help us? Thanks in advance Simone de Blasiis
On 22/04/2022 10.46, [EXT] Henning Westerholt wrote:
Hello,
I did not look in the RFC regarding the removing the video line in questions. You are probably referring to the sdp_remove_media() function.
Do you expect problems when you are doing this? A quick web search found a similar suggestion also e.g. for Cisco router and others.
The problem with simply removing a media section is that the answer going back to the A-side will have mismatched media sections, which is invalid according to the RFC.
You can remove the video media section in the offer going from A to B, but in the answer from B to A the media section should be restored with the port set to zero, indicating a rejected media section. Since the answer from B won't contain a section for the video, a new `m=` must be inserted in the SDP going back to A, matching the `m=` originally presented by A.
Cheers
Hello Henning, thanks for the suggestions. You are right, I was referring to the sdp_remove_media() function. In the documentation https://kamailio.org/docs/modules/5.5.x/modules/sdpops.html#sdpops.f.sdp_remove_media of the sdpops modules it cites RFC 3264 and it says that the number of m= lines must be the same for both the offer and the answer. We have experienced issues ourselves with this solution so it's not viable.
Sadly we can't return 415 either because it would mean that the call would be dropped. We have some devices that will always offer the video and that won't strip it in any occasion from their invites.
Our only solution is to find a way of doing it ourselves with either Kamailio or rtpengine.
Regards
Simone
Il giorno ven 22 apr 2022 alle ore 16:46 Henning Westerholt hw@gilawa.com ha scritto:
Hello,
I did not look in the RFC regarding the removing the video line in questions. You are probably referring to the sdp_remove_media() function.
Do you expect problems when you are doing this? A quick web search found a similar suggestion also e.g. for Cisco router and others.
Another option would be to just return a 415 on the proxy level, by also adding the supported types to the Accept header, like this:
Accept: audio/*
Cheers,
Henning
--
Henning Westerholt – https://skalatan.de/blog/
Kamailio services – https://gilawa.com
*From:* sr-users sr-users-bounces@lists.kamailio.org *On Behalf Of *Simone de Blasiis *Sent:* Friday, April 22, 2022 4:32 PM *To:* sr-users@lists.kamailio.org *Subject:* [SR-Users] How to disable video in invite with both audio and video
Hello to everyone,
we have a Kamailio 5.5 + RTPEngine deployment. Some devices will send an invite with both audio and video in the offer and we are trying to disable the video portion of the invite by either setting the video port to 0 or by setting a=inactive in the video portion of the SDP packet.
We know that sdpops has a function that would be able to remove the video portion but it violates standards so we can't use it. We need to disable the video in the SDP offers because one of the pstn providers we are using doesn't accept invites that contain a video offer.
I've spent days searching but I can't find an obvious way of achieving this.
We were originally doing it with textops but we've been having some issues where the sdp wouldn't be modified correctly in reinvites after the original call is in place so we're looking for alternatives.
Can someone please help us? Thanks in advance
Simone de Blasiis
Hello,
Ok, understood – have a look to the reply from Richard in this e-mail thread, he also provided a standard compliant suggestion.
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.comhttps://gilawa.com/
From: Simone de Blasiis simone.deblasiis@teameis.it Sent: Friday, April 22, 2022 5:33 PM To: Henning Westerholt hw@gilawa.com Cc: Kamailio (SER) - Users Mailing List sr-users@lists.kamailio.org Subject: Re: [SR-Users] How to disable video in invite with both audio and video
Hello Henning, thanks for the suggestions. You are right, I was referring to the sdp_remove_media() function. In the documentationhttps://kamailio.org/docs/modules/5.5.x/modules/sdpops.html#sdpops.f.sdp_remove_media of the sdpops modules it cites RFC 3264 and it says that the number of m= lines must be the same for both the offer and the answer. We have experienced issues ourselves with this solution so it's not viable.
Sadly we can't return 415 either because it would mean that the call would be dropped. We have some devices that will always offer the video and that won't strip it in any occasion from their invites.
Our only solution is to find a way of doing it ourselves with either Kamailio or rtpengine.
Regards
Simone
Il giorno ven 22 apr 2022 alle ore 16:46 Henning Westerholt <hw@gilawa.commailto:hw@gilawa.com> ha scritto: Hello,
I did not look in the RFC regarding the removing the video line in questions. You are probably referring to the sdp_remove_media() function.
Do you expect problems when you are doing this? A quick web search found a similar suggestion also e.g. for Cisco router and others.
Another option would be to just return a 415 on the proxy level, by also adding the supported types to the Accept header, like this: Accept: audio/*
Cheers,
Henning
-- Henning Westerholt – https://skalatan.de/blog/ Kamailio services – https://gilawa.comhttps://gilawa.com/
From: sr-users <sr-users-bounces@lists.kamailio.orgmailto:sr-users-bounces@lists.kamailio.org> On Behalf Of Simone de Blasiis Sent: Friday, April 22, 2022 4:32 PM To: sr-users@lists.kamailio.orgmailto:sr-users@lists.kamailio.org Subject: [SR-Users] How to disable video in invite with both audio and video
Hello to everyone, we have a Kamailio 5.5 + RTPEngine deployment. Some devices will send an invite with both audio and video in the offer and we are trying to disable the video portion of the invite by either setting the video port to 0 or by setting a=inactive in the video portion of the SDP packet. We know that sdpops has a function that would be able to remove the video portion but it violates standards so we can't use it. We need to disable the video in the SDP offers because one of the pstn providers we are using doesn't accept invites that contain a video offer. I've spent days searching but I can't find an obvious way of achieving this. We were originally doing it with textops but we've been having some issues where the sdp wouldn't be modified correctly in reinvites after the original call is in place so we're looking for alternatives. Can someone please help us? Thanks in advance Simone de Blasiis
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Henning Westerholt -
Richard Fuchs -
Simone de Blasiis