Vibecoded Bash Script to Check SBC Bitpool & Bitrate

sbc_check.sh

#!/usr/bin/env bash
# Thanks gemini
# Also since im on Gentoo, this DOESN't need systemd! (Should work on systemd still I think)
set -eo pipefail

# Dependency check
if ! command -v busctl &> /dev/null; then
    echo "Error: 'busctl' is not installed."
    exit 1
fi

echo "Scanning for Bluetooth Audio Transports..."
echo "----------------------------------------------------------------------------------------------------"
printf "%-25s | %-12s | %-10s | %-30s\n" "Device Address" "Status" "Codec" "Details / Bitrate"
echo "----------------------------------------------------------------------------------------------------"

# 1. Find all Transport paths
# We use grep -oE to reliably grab the path ending in fdX
mapfile -t paths < <(busctl --system tree org.bluez | grep -oE '/org/bluez/.*fd[0-9]+')

if [ ${#paths[@]} -eq 0 ]; then
    echo "No audio transports found. Ensure headphones are connected."
    exit 0
fi

for path in "${paths[@]}"; do
    # Extract clean MAC address for display
    device_addr=$(echo "$path" | grep -o 'dev_[^/]*' | sed 's/dev_//;s/_/:/g')

    # 2. Get State
    # CHANGED: 'get' -> 'get-property', removed 2>/dev/null
    # We use || true so the script doesn't crash if a device disconnects mid-loop
    raw_state=$(busctl --system get-property org.bluez "$path" org.bluez.MediaTransport1 State || true)
    
    if [[ -z "$raw_state" ]]; then
        printf "%-25s | %-12s | %-10s | %-30s\n" "$device_addr" "ERROR" "-" "Device vanished or call failed"
        continue
    fi
    
    # Parse: Output is usually 's "active"'
    state=$(echo "$raw_state" | cut -d' ' -f2 | tr -d '"')

    # 3. Get Codec ID
    # CHANGED: 'get' -> 'get-property'
    raw_codec=$(busctl --system get-property org.bluez "$path" org.bluez.MediaTransport1 Codec)
    codec_id=$(echo "$raw_codec" | cut -d' ' -f2)

    # Determine Codec Name
    case "$codec_id" in
        0) codec_name="SBC" ;;
        1) codec_name="MPEG" ;;
        2) codec_name="AAC" ;;
        255) codec_name="Vendor" ;;
        *) codec_name="ID:$codec_id" ;;
    esac

    # --- CHECK: IDLE ---
    if [[ "$state" != "active" ]]; then
        printf "%-25s | %-12s | %-10s | %-30s\n" "$device_addr" "IDLE" "$codec_name" "Stream paused/inactive"
        continue
    fi

    # --- CHECK: NON-SBC ---
    if [[ "$codec_id" != "0" ]]; then
        printf "%-25s | %-12s | %-10s | %-30s\n" "$device_addr" "ACTIVE" "$codec_name" "Not SBC (Skipping calc)"
        continue
    fi

    # 4. Parse SBC Configuration
    # CHANGED: 'get' -> 'get-property'
    raw_config=$(busctl --system get-property org.bluez "$path" org.bluez.MediaTransport1 Configuration)
    
    # Output is like: "ay 4 20 21 53 53"
    # We want everything after the 3rd space to get the bytes
    config_bytes=$(echo "$raw_config" | cut -d' ' -f3-)
    read -r -a config_arr <<< "$config_bytes"

    # --- DECODE SBC ---
    # Byte 0: Frequency & Channel Mode
    b0=${config_arr[0]}
    
    if   (( (b0 & 16) )); then freq=48000; freq_str="48kHz"
    elif (( (b0 & 32) )); then freq=44100; freq_str="44.1kHz"
    elif (( (b0 & 64) )); then freq=32000; freq_str="32kHz"
    else freq=16000; freq_str="16kHz"; fi

    if   (( (b0 & 1) )); then ch_mode="JointStereo"; channels=2; join=1
    elif (( (b0 & 2) )); then ch_mode="Stereo";      channels=2; join=0
    elif (( (b0 & 4) )); then ch_mode="DualChannel"; channels=2; join=0
    else                      ch_mode="Mono";        channels=1; join=0; fi

    # Byte 1: Blocks, Subbands
    b1=${config_arr[1]}
    if   (( (b1 & 16) )); then blocks=16
    elif (( (b1 & 32) )); then blocks=12
    elif (( (b1 & 64) )); then blocks=8
    else blocks=4; fi

    if   (( (b1 & 4) )); then subbands=8
    else subbands=4; fi

    # Byte 3: Max Bitpool
    bitpool=${config_arr[3]}

    # --- CALCULATE BITRATE ---
    header_part=$(( 4 + (4 * subbands * channels) / 8 ))

    if [[ "$ch_mode" == "DualChannel" ]] || [[ "$ch_mode" == "Mono" ]]; then
        bits_payload=$(( blocks * channels * bitpool ))
    else
        bits_payload=$(( (join * subbands) + (blocks * bitpool) ))
    fi

    payload_bytes=$(( (bits_payload + 7) / 8 ))
    frame_len=$(( header_part + payload_bytes ))
    bitrate_bps=$(( (8 * frame_len * freq) / (subbands * blocks) ))
    bitrate_kbps=$(( bitrate_bps / 1000 ))

    # Print Active SBC Row
    info_str="BP:$bitpool | $ch_mode | $freq khz | $bitrate_kbps kbps"
    printf "%-25s | %-12s | %-10s | %-30s\n" "$device_addr" "ACTIVE" "$codec_name" "$info_str"

done

I just manually edited and applied https://github.com/ezrakhuzadi/bluetooth-bitrate-manager/blob/e300d7e1ee3857132a4c43d23c96c122c17968d2/bluetooth_bitrate_manager/resources/pipewire-sbc-custom-bitpool.patch lol

Didn't want it messing with directly installing over when I already have Gentoo's extremely convenient patching system.