How to record what you hear and what you see, to 1 mp3-file? Do this!

Get Names of your devices

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Mono-Micro + Head-phones to 1 file - works fine

ffmpeg \
-f pulse -ac 2 -ar 48000 -i alsa_output.usb-C-Media_Electronics_Inc._USB_PnP_Sound_Device-00.analog-stereo.monitor \
-f pulse -ac 1 -ar 48000 -i alsa_input.usb-Solid_State_System_Co._Ltd._LCS_USB_Audio_000000000000-00.mono-fallback \
-filter_complex amix=inputs=2 \
-acodec libmp3lame -ar 48000 -q:a 1 \
all.mp3

Credits to MrWhat!