iOS 14.0.1 crashes with bundled WebRTC.framework when calling (begin|end)GeneratingDeviceOrientationNotifications M69 and M75 but not M84

[pasmat]

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• [*] I have used Google with the error message or bug in association with the library and Cordova words to make sure the issue I'm reporting is only related to iOSRTC.
• I have provided steps to reproduce (e.g. sample code or updated extra/renderer-and-libwebrtc-tests.js file).
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Versions affected

• Cordova version 10.0.0:
• Cordova iOS version 6.1.1:
• Plugin version master branch:
• iOS version 14.0.1:
• Xcode version 12.0.1:
• WebRTC-adapter version 7.4.0:
• WebRTC Framework version M69:

Description

The bundled WebRTC Framework causes crash, due to RTCCameraVideoCapturer.startCapture calling UIDevices beginGeneratingDeviceOrientationNotifications on non main thread

I used the linked guide to build WebRTC framework and modified RTCCameraVideoCapturer.m so that instead of calling the beginGeneratingDeviceOrientationNotifications and endGeneratingDeviceOrientationNotifications via RTCDispatchers RTCDispatcherTypeCaptureSession, I call them on RTCDispatcherTypeMain, and it works as expected.

I can't find any documentation regarding the changes to this functions behavior on iOS 14, but this works as expected on my iPad running iOS 13, and used to work on my iPhone running iOS 14.

Steps to reproduce

Run anything on iOS 14.0.1 that accesses the camera using cordova-plugin-iosrtc

Expected results

No crash

Actual results

Crash
*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'threading violation: expected the main thread'

[hthetiot]

hello @pasmat you modifed RTCCameraVideoCapturer.m in your WebRTC build ?
can you provide a diff.

[hthetiot]

can you try M72 and M84

• update WebRTC.framework to M79 #475
• update WebRTC.framework to M87 #545

[agelito]

Hello @hthetiot I've tried M84 #545 and it doesn't crash on iOS 14.0.1 iPad Air 2.

[pasmat]

diff webrtc-M69/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m webrtc-M69\ 2/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m

156,158d155
<   [RTCDispatcher
<       dispatchAsyncOnType:RTCDispatcherTypeMain
<                     block:^{
160d156
<                     }];
201,203d196
<   [RTCDispatcher
<       dispatchAsyncOnType:RTCDispatcherTypeMain
<                     block:^{
205d197
<                     }];

Here's the diff for M69 WebRTC that fixes it for 14.0.1.

If this is fixed on M84 as suggested by @agelito - that's must be the better fix, if it has no other compatibility issues.

Thanks.

[hthetiot]

First, it does not crash for me at all on iOS 14.0.1 so fare on iPad Pro and iPhone 6 and 11 on 14.0.1.
Second, thank you @pasmat for the diff, i did edit your comment to make the diff more readable, but its not clear for me, did you simply remove the RTCDispatcher to use main thread ?

[hthetiot]

I have provided steps to reproduce (e.g. sample code or updated extra/renderer-and-libwebrtc-tests.js file).

Can you provide a modified extra/renderer-and-libwebrtc-tests.js file to reproduce ? you did not exactly provided it.

Notice I cannot reproduce this issue, can you also try cordova 9 for me.

[hthetiot]

Here is minor update on BuildWebRTCLib to support Xcode 12:

• Fix Build webrtc using xcode 12 react-native-webrtc/react-native-webrtc#883

@pasmat did you have warning that where treated as errors, if not, what version of Xcode are you using?

[hthetiot]

Updated difff from @pasmat
diff --git i/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m w/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m

index 8f93937c75..e21cc76280 100644
--- i/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m
+++ w/sdk/objc/Framework/Classes/PeerConnection/RTCCameraVideoCapturer.m
@@ -148,7 +148,7 @@ const int64_t kNanosecondsPerSecond = 1000000000;
              completionHandler:(nullable void (^)(NSError *))completionHandler {
   _willBeRunning = YES;
   [RTCDispatcher
-      dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
+      dispatchAsyncOnType:RTCDispatcherTypeMain
                     block:^{
                       RTCLogInfo("startCaptureWithDevice %@ @ %ld fps", format, (long)fps);

@@ -184,7 +184,7 @@ const int64_t kNanosecondsPerSecond = 1000000000;
 - (void)stopCaptureWithCompletionHandler:(nullable void (^)(void))completionHandler {
   _willBeRunning = NO;
   [RTCDispatcher
-      dispatchAsyncOnType:RTCDispatcherTypeCaptureSession
+      dispatchAsyncOnType:RTCDispatcherTypeMain
                     block:^{
                       RTCLogInfo("Stop");
                       _currentDevice = nil;

testing fix now.

[hthetiot]

@pasmat can you test the PR there #585 (see instructions).
I confirmed the fix, but something odd is that existing application i have are working fine without this fix, only iosrtc-sample seem to be able to reproduce.

[hthetiot]

I'm closing for now, please comment if fix not working but it does for me.