Intel® Collaboration Suite for WebRTC
Community support and discussions on the Intel® Collaboration Suite for WebRTC (Intel® CS for WebRTC).
Welcome to the Intel Community. If you get an answer you like, please mark it as an Accepted Solution to help others. Thank you!
For the latest information on Intel’s response to the Log4j/Log4Shell vulnerability, please see Intel-SA-00646
1136 Discussions

Subscribing from safari ios SDP offer error. ios 12.3

New Contributor I

I think ios 12.3 may have changed something.

Now when I try to subscribe to a forward stream in safari, I get the following error:

InvalidAccessError: Failed to set remote answer sdp: The order of m-lines in answer doesn't match order in offer. Rejecting answer.

The streams are from chrome and firefox, both do not work.

Could someone please verify if they can subscribe successfully from ios 12.3 safari on an iphone? I am only publishing video only streams, no audio.

I hope to fix this quickly because now all my iphone users are annoyed :( .


0 Kudos
4 Replies
New Contributor I


It appears that there is a unified plan bug. If you go into the Advanced Experimental Features on safari and switch OFF webrtc unified plan, then you can subscribe like normal.

Please try to fix this bug (but dont just switch us back to non-unified!!!) as we don't know when Apple may decide to drop non-unified support.

I'm glad there is a workaround for now, but I don't want too many users to flip that switch!

New Contributor I

Has anyone had a chance to test this further? From my understanding intel webrtc is incompatible with the latest safari ios with default settings. That's quite a big hit to my user base.


Hi Stephen,

This issue is expected to be fixed

New Contributor I

Thanks Jianjun, do you know when the next official version is expected to be released?

And have you guys been testing with ios 13 yet? It's set for release in just a couple of months.

I had one user who was only seeing black cams on ios 13, even with unified plan turned off, but I haven't been able to test it myself yet!


I must be honest, I'm getting an urge to consider switching away to a different webrtc platform like mediasoup.

So many users want to move to firefox, but intel webrtc can't yet limit the upload bandwidth of firefox. This means I can't allow a resolution more than 240p, because 480p uses way too much bandwidth. BUT, to make matters worse, firefox will not resize webcams, so webcams that only support 480p (but not 240p!) simply cannot use my website. I wish 

If I could just limit the upload rate on firefox that would be good enough. I definitely think this should be a high priority, people are getting very annoyed with the chrome browser.