System information (version)

OpenCV version: 4.5.1 or 4.2.0
Platform: OS X 11.1
Compiler: Apple clang version 12.0.0 (clang-1200.0.32.29) x86_64-apple-darwin20.3.0

Detailed description

Opened VideoCapture fails on assertion when calling getBackendName():

libc++abi.dylib: terminating with uncaught exception of type cv::Exception: OpenCV(4.5.1) /Users/user/app/build.release/opencv/src/opencv-pe/modules/videoio/src/cap.cpp:299: error: (-215:Assertion failed) api != 0 in function 'getBackendName'

Error: signal 6:

Steps to reproduce

1. Create and open instance of VideoCapture (e.g. using device 0).
2. Call getBackendName() method.