Ffmpeg-f android_camera has blocked data that can not read the camera

I want to read the android camera via ffmpeg and save it to a file, but I block the process of reading the camera.Here are the commands that I have used:
ffmpeg -loglevel trace -f android_camera -camera_index 0 -video_size hd720 -framerate 30 -input_queue_size 2 -i ignored -map 0 -c copy output.raw