Crash when reading video frame bits on Android

I'm using a "wrapper" QAbstractVideoSurface to intercept video frames between a QML Camera and VideoOutput items.

When I try to map() the QVideoFrame, I get the following error:

checkAndUpdateEglState: invalid current EGLDisplay

This error bubbles up as a Java exception which is not handled, resulting in a JNI error later on:

JNI DETECTED ERROR IN APPLICATION: JNI NewFloatArray called with pending exception 'java.lang.IllegalStateException' thrown in unknown throw location
F/art     (21903): sart/runtime/check_jni.cc:65]     in call to NewFloatArray

The problem is caused by the fact that AndroidTextureVideoBuffer::map() results in EGL calls on a thread without an active EGL context.

I've tried using QAbstractVideoFilter instead of this stacking approach, but the results are the same.