iOS switches video codec from "H264" to "VP8" on app state change

General040642add70aa006ef56b5af5b5acae3
1

When app state changes from “background” to “foreground”. iOS seems to change video codec from “H264” to “VP8” on it’s own.

I’m using Kurento Media server and peer connection gets disconnected because it cannot sync the video track.

Kurrento Server Logs

error rtpsynchronizer           
kmsrtpsynchronizer.c:454 
kms_rtp_synchronizer_process_rtp_buffer_mapped() 
<KmsRtpSynchronizer@0x7fbe58012790>  
Unknown PT: 100, expected: 96

PT 100 is VP8 and 96 is H264

I have tried disabling the video track before putting app to the background state and enabling when it comes back to foreground. Peer connection remains connected but when video track is enabled, kurrento server throws codec mismatch error.

Version: WebRTC 111.0.1
Platform: iOS
React Native: 0.69.5

2

Bit of an unusual issue.
Have you tried altering the SDP to force the use of the h264 codec?

3

@8BallBomBom Yes, it works with forcing either H264 or VP8.
But would be great to find the underlying issue here.