Live audio metrics monitor for PipeWire/PulseAudio mic input

mic-monitor.sh

#!/bin/bash
# Live audio metrics from the Yeti Nano mic
# Usage: mic-monitor.sh [duration_seconds] (default: 10)

DURATION="${1:-10}"
SOURCE="alsa_input.usb-Blue_Microphones_Yeti_Nano_2538SQ903SB8_888-000476140506-00.analog-stereo"

echo "Recording $DURATION seconds from Yeti Nano..."
echo

ffmpeg -f pulse -i "$SOURCE" -t "$DURATION" -af "astats=metadata=1:reset=0.5,ametadata=print:key=lavfi.astats.Overall.RMS_level:file=-:direct=1,ametadata=print:key=lavfi.astats.Overall.Peak_level:file=-:direct=1,ametadata=print:key=lavfi.astats.Overall.Flat_factor:file=-:direct=1" -vn -f null /dev/null 2>/dev/null | \
awk -F= '
/RMS_level/  { rms=$2; rms_sum+=$2; rms_n++; if(rms_min=="" || $2<rms_min) rms_min=$2; if($2>rms_max) rms_max=$2 }
/Peak_level/ { peak=$2; if(peak_max=="" || $2>peak_max) peak_max=$2; if($2 >= -0.1) clips++ }
/Flat_factor/ {
    printf "\r  RMS: %7.1f dB | Peak: %7.1f dB | Max Peak: %7.1f dB | Clips: %d  ", rms, peak, peak_max, clips+0
}
END {
    printf "\n\n"
    printf "=== Summary ===\n"
    printf "  Avg RMS:   %7.1f dB\n", (rms_n>0 ? rms_sum/rms_n : -999)
    printf "  RMS range: %7.1f to %.1f dB\n", rms_min, rms_max
    printf "  Max Peak:  %7.1f dB\n", peak_max
    printf "  Clips:     %d\n", clips+0
    if (peak_max > -1) printf "  ⚠ CLIPPING DETECTED\n"
    else if (peak_max > -6) printf "  ⚠ Hot - consider reducing gain\n"
    else if (peak_max > -20) printf "  ✓ Good levels\n"
    else printf "  ⚠ Quiet - consider increasing gain\n"
}'