Capture audio from desktop + mic with pulseaudio

capture-audio.sh

#!/bin/bash

#
# Usage:
#
# capture-audio.sh [ffmpeg args]
#

function get_default_sink_or_source() {
    SINK_OR_SOURCE=$1
    pacmd list-${SINK_OR_SOURCE}s |\
        grep -F -A1 \* |\
        tail -n1 |\
        sed -e 's/.*<\(.*\)>/\1/'
}

DEFAULT_INPUT="$(get_default_sink_or_source source)"
DEFAULT_OUTPUT="$(get_default_sink_or_source sink).monitor"

echo "Capturing from"
echo "Microphone: ${DEFAULT_INPUT}"
echo "Desktop audio: ${DEFAULT_OUTPUT}"
echo

if [ "$#" -gt 1 ]; then
    ARGS="$@"
else
    ARGS="${HOME}/$(date +%F_%H%M%S).mp3"
fi

exec ffmpeg -f pulse -i ${DEFAULT_INPUT} \
    -f pulse -i ${DEFAULT_OUTPUT} \
    -filter_complex amix=inputs=2 \
    ${ARGS}