ffmpeg -f avfoundation -framerate 30 -i "1:0" \
-f avfoundation -framerate 30 -video_size 640x480 -i "0" \
-c:v libx264 -preset ultrafast \
-filter_complex 'overlay=main_w-overlay_w-10:main_h-overlay_h-10' \
-acodec libmp3lame -ar 44100 -ac 1 \
-f flv rtmp://localhost/live1/room1