code: private VideoCapturer getVideoCapturer() {
          String[] cameraFacing = {"front", "back"};
          int[] cameraIndex = {0, 1};
          int[] cameraOrientation = {0, 90, 180, 270};
          for (String facing : cameraFacing) {
              for (int index : cameraIndex) {
                  for (int orientation : cameraOrientation) {
                      String name = "Camera " + index + ", Facing " + facing +
                              ", Orientation " + orientation;
                      VideoCapturer capturer = VideoCapturer.create(name);
                      if (capturer != null) {
                          return capturer;
                      }
                  }
              }
          }
          throw new RuntimeException("Failed to open capturer");
      }
docs: capturer that works, or crash if none do.