This script mutes Spotify when it plays advertisements.

spotisilencer.py

#!/usr/bin/env python3
# encoding: utf-8

import sys
import dbus
import dbus.mainloop.glib
import subprocess
import time
import re
from gi.repository import GLib

# copied from https://github.com/avindra/pacmd-python
def parseList(output):
    lines = output.split('\n')
    first = lines.pop(0)
    if first.startswith('Unknown command'):
        raise Exception(first)
    data = {}
    currentItem = {}
    currentIndex = -1
    patternNewItem = re.compile('(\* )?index: (\d+)')
    patternKeyValue = re.compile('\t*([^:]+):(?: (.+))?')
    patternEnumerating = re.compile('^\tproperties:')
    patternProps = re.compile('(\S+) = "(.+)"')
    enumeratingProps = None
    lastKey = None
    for line in lines:
        matchNewItem = patternNewItem.search(line)
        matchKeyValue = patternKeyValue.search(line)
        matchEnumerating = patternEnumerating.search(line)
        if enumeratingProps:
            matchProps = patternProps.search(line)
            if matchProps:
                enumeratingProps[matchProps.group(1)] = matchProps.group(2)
                continue
            else: # reset
                currentItem['properties'] = enumeratingProps
                enumeratingProps = None
        if matchEnumerating:
            enumeratingProps = { 'device-api' : None }
        elif matchNewItem:
            isActive = matchNewItem.group(1) == '* '
            index = matchNewItem.group(2)
            # Finalize object and reset
            if currentIndex != -1:
                data[currentIndex] = currentItem
                currentItem = {}
            currentIndex = index
            if isActive:
                data['activeItem'] = index
        elif matchKeyValue:
            parsedKey = matchKeyValue.group(1).strip()
            parsedValue = matchKeyValue.group(2)
            # skip until we're out of "ports".
            # not currently supported
            if lastKey == 'ports' and parsedKey != 'active port':
                continue
            lastKey = parsedKey
            currentItem[parsedKey] = parsedValue
        elif lastKey and lastKey != 'ports': # If it gets to here, we can assume its a multiline attr
            currentItem[lastKey] += re.sub('^\s+', '\n', line)
    # Last item will need to be pushed manually
    data[currentIndex] = currentItem
    return data

def pacmd_list_sink_inputs():
    p = subprocess.Popen(['pacmd','list-sink-inputs'], stdout=subprocess.PIPE, encoding='utf-8')
    out, err = p.communicate()
    return parseList(out)

def pacmd_set_sink_input_mute(index, mutestate):
    p = subprocess.Popen(['pacmd','set-sink-input-mute', index, mutestate])
    out, err = p.communicate()

def pulse_mute_spotify(mutestate):
    inputs = pacmd_list_sink_inputs()
    # spotify may allocate more than one output
    spotify_indices = [
        index for index, sink in inputs.items()
        if 'properties' in sink and sink['properties']['application.process.binary'] == 'spotify'
    ]
    for spotify_index in spotify_indices:
        pacmd_set_sink_input_mute(spotify_index, mutestate)
    print('Set mutestate to %s for %s'%(mutestate, str(spotify_indices)))

def is_advert(metadata):
    """ Whether the current song is an advertisement. """
    if 'Metadata' in metadata:
        m = metadata['Metadata']
        artist = m['xesam:artist'][0]
        return artist == ""
    else:
        return False

def propertiesChanged_handler(sender=None, metadata=None, sig=None):
    time.sleep(0.5) # event comes a bit earlier than actual content change
    is_ad = is_advert(metadata)
    pulse_mute_spotify('1' if is_ad else '0')

def main():
    dbus.mainloop.glib.DBusGMainLoop(set_as_default=True)
    bus = dbus.SessionBus()
    try:
        remote_object = bus.get_object(
            "org.mpris.MediaPlayer2.spotify",
            "/org/mpris/MediaPlayer2"
        )
        change_manager = dbus.Interface(
            remote_object,
            'org.freedesktop.DBus.Properties'
        )
        change_manager.connect_to_signal(
            "PropertiesChanged",
            propertiesChanged_handler
        )
    except dbus.exceptions.DBusException as dbe:
        if (dbe.get_dbus_name() == "org.freedesktop.DBus.Error.ServiceUnknown"):
            print("Please start Spotify first. (%s)"%(dbe.get_dbus_message()))
            sys.exit(1)
    loop = GLib.MainLoop()
    loop.run()

if __name__ == '__main__':
    main()