WebView crash when accessing camera on Android R + external camera HAL

[Michael Goffioul]

I'm using a webview-based app on a device running Android R. The device only has the external camera HAL enabled: android.hardware...@2.5-external-service. And the device has one USB camera connected to it.

The webview is self-compiled @ 88.0.4324.181 (but I can reproduce the problem also with 87.0.4280.66).

When the webview attempts to access the camera (e.g. navigator.mediaDevices.getUserMedia({video:true,audio:true})), the whole app crashes and logcat contains entries about invalid camera index followed by a NullPointerException. The invalid camera index message comes from here:

https://source.chromium.org/chromium/chromium/src/+/refs/tags/88.0.4324.181:media/capture/video/android/java/src/org/chromium/media/VideoCaptureCamera2.java;l=1027;bpv=0;bpt=0

and the NullPointerException is simply a consequence of getCameraCharacteristics() returning null. The uncaught java exception is then handled in jni_android.cc and triggers the app crash. I added some more extensive debug information and determined that when the problem occurs:

index = 100

cameraIdList = [ "100" ]

So it seems that chromium code assumes the camera ID is identical to a 0-based index, but this is not valid in this case. The value 100 is coming from the default ID offset used in the external camera HAL:

https://cs.android.com/android/platform/superproject/+/android-11.0.0_r3:hardware/interfaces/camera/device/3.4/default/ExternalCameraUtils.cpp;l=706

Is this a bug in webview/chromium, or is it just that the external camera HAL is not (supposed to be) supported?

Michael.

[Torne (Richard Coles)]

Does this same issue happen in Chrome on this device? This doesn't seem likely to be WebView-specific, and so you're more likely to find someone who can help if you can reproduce it in Chrome and file a bug against Chrome. The WebView team don't have detailed knowledge about many of the common parts of Chromium code like the media support.

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[Michael Goffioul]

Yes, Chrome also crashes the same way. I'll file a bug against Chrome, then.

[Eyasin Mollah]

Hi, Michael. Have you been able to fix the error in webview and Chrome?

[Michael Goffioul]

You can find the bug report here: https://bugs.chromium.org/p/chromium/issues/detail?id=1183362
A change has been integrated into Chrome, which avoids the crash. The more correct approach of handling camera ID as string (and not integer) has never been done, to my knowledge.