Extracted `AudioRecorder` out of `SoundPlugin`.

platypush/plugins/sound/__init__.py

@@ -1,42 +1,24 @@
+from collections import defaultdict
 import os
 import queue
 import stat
-import time
+from typing_extensions import override
 import warnings
 
-from enum import Enum
+from threading import Event, RLock
-from threading import Thread, Event, RLock
+from typing import Dict, Optional, Union
-from typing import Optional, Union
 
 import sounddevice as sd
 import soundfile as sf
 
-from platypush.context import get_bus
+from platypush.plugins import RunnablePlugin, action
-from platypush.message.event.sound import (
-    SoundRecordingStartedEvent,
-    SoundRecordingStoppedEvent,
-)
-
-from platypush.plugins import Plugin, action
-from platypush.utils import get_redis
 
 from .core import Sound, Mix
-from ._converter import ConverterProcess
+from ._controllers import AudioRecorder
+from ._model import AudioState
 
 
-class PlaybackState(Enum):
+class SoundPlugin(RunnablePlugin):
-    STOPPED = 'STOPPED'
-    PLAYING = 'PLAYING'
-    PAUSED = 'PAUSED'
-
-
-class RecordingState(Enum):
-    STOPPED = 'STOPPED'
-    RECORDING = 'RECORDING'
-    PAUSED = 'PAUSED'
-
-
-class SoundPlugin(Plugin):
     """
     Plugin to interact with a sound device.
 
@@ -105,24 +87,36 @@ class SoundPlugin(Plugin):
         self.playback_state_lock = RLock()
         self.playback_paused_changed = {}
         self.stream_mixes = {}
-        self.recording_state = RecordingState.STOPPED
-        self.recording_state_lock = RLock()
-        self.recording_paused_changed = Event()
         self.active_streams = {}
         self.stream_name_to_index = {}
         self.stream_index_to_name = {}
         self.completed_callback_events = {}
         self.ffmpeg_bin = ffmpeg_bin
 
+        self._recorders: Dict[str, AudioRecorder] = {}
+        self._recorder_locks: Dict[str, RLock] = defaultdict(RLock)
+
     @staticmethod
-    def _get_default_device(category):
+    def _get_default_device(category: str) -> str:
         """
         Query the default audio devices.
 
         :param category: Device category to query. Can be either input or output
-        :type category: str
         """
-        return sd.query_hostapis()[0].get('default_' + category.lower() + '_device')  # type: ignore
+        host_apis = sd.query_hostapis()
+        assert host_apis, 'No sound devices found'
+        available_devices = list(
+            filter(
+                lambda x: x is not None,
+                (
+                    host_api.get('default_' + category.lower() + '_device')  # type: ignore
+                    for host_api in host_apis
+                ),
+            ),
+        )
+
+        assert available_devices, f'No default "{category}" device found'
+        return available_devices[0]
 
     @action
     def query_devices(self, category=None):
@@ -175,10 +169,10 @@ class SoundPlugin(Plugin):
         is_raw_stream = streamtype == sd.RawOutputStream
 
         def audio_callback(outdata, frames, *, status):
-            if self._get_playback_state(stream_index) == PlaybackState.STOPPED:
+            if self._get_playback_state(stream_index) == AudioState.STOPPED:
                 raise sd.CallbackStop
 
-            while self._get_playback_state(stream_index) == PlaybackState.PAUSED:
+            while self._get_playback_state(stream_index) == AudioState.PAUSED:
                 self.playback_paused_changed[stream_index].wait()
 
             if frames != blocksize:
@@ -378,7 +372,7 @@ class SoundPlugin(Plugin):
                     finished_callback=completed_callback_event.set,
                 )
 
-                self._start_playback(stream_index=stream_index, stream=stream)
+                self.start_playback(stream_index=stream_index, stream=stream)
 
             with stream:
                 # Timeout set until we expect all the buffered blocks to
@@ -386,9 +380,7 @@ class SoundPlugin(Plugin):
                 timeout = blocksize * bufsize / samplerate
 
                 while True:
-                    while (
+                    while self._get_playback_state(stream_index) == AudioState.PAUSED:
-                        self._get_playback_state(stream_index) == PlaybackState.PAUSED
-                    ):
                         self.playback_paused_changed[stream_index].wait()
 
                     if f:
@@ -412,23 +404,20 @@ class SoundPlugin(Plugin):
                         if duration is not None and t >= duration:
                             break
 
-                    if self._get_playback_state(stream_index) == PlaybackState.STOPPED:
+                    if self._get_playback_state(stream_index) == AudioState.STOPPED:
                         break
 
                     try:
                         q.put(data, timeout=timeout)
                     except queue.Full as e:
-                        if (
+                        if self._get_playback_state(stream_index) != AudioState.PAUSED:
-                            self._get_playback_state(stream_index)
-                            != PlaybackState.PAUSED
-                        ):
                             raise e
 
                 completed_callback_event.wait()
         except queue.Full:
             if (
                 stream_index is None
-                or self._get_playback_state(stream_index) != PlaybackState.STOPPED
+                or self._get_playback_state(stream_index) != AudioState.STOPPED
             ):
                 self.logger.warning('Playback timeout: audio callback failed?')
         finally:
@@ -450,6 +439,81 @@ class SoundPlugin(Plugin):
 
         return self.record(*args, **kwargs)
 
+    def create_recorder(
+        self,
+        device: str,
+        output_device: Optional[str] = None,
+        fifo: Optional[str] = None,
+        outfile: Optional[str] = None,
+        duration: Optional[float] = None,
+        sample_rate: Optional[int] = None,
+        dtype: str = 'int16',
+        blocksize: Optional[int] = None,
+        latency: Union[float, str] = 'high',
+        channels: int = 1,
+        redis_queue: Optional[str] = None,
+        format: str = 'wav',  # pylint: disable=redefined-builtin
+        stream: bool = True,
+        play_audio: bool = False,
+    ) -> AudioRecorder:
+        with self._recorder_locks[device]:
+            assert self._recorders.get(device) is None, (
+                f'Recording already in progress for device {device}',
+            )
+
+            if play_audio:
+                output_device = (
+                    output_device
+                    or self.output_device
+                    or self._get_default_device('output')
+                )
+
+                device = (device, output_device)  # type: ignore
+                input_device = device[0]
+            else:
+                input_device = device
+
+            if sample_rate is None:
+                dev_info = sd.query_devices(device, 'input')
+                sample_rate = int(dev_info['default_samplerate'])  # type: ignore
+
+            if blocksize is None:
+                blocksize = self.input_blocksize
+
+            if fifo:
+                fifo = os.path.expanduser(fifo)
+                if os.path.exists(fifo) and stat.S_ISFIFO(os.stat(fifo).st_mode):
+                    self.logger.info('Removing previous input stream FIFO %s', fifo)
+                    os.unlink(fifo)
+
+                os.mkfifo(fifo, 0o644)
+                outfile = fifo
+            elif outfile:
+                outfile = os.path.expanduser(outfile)
+
+            outfile = outfile or fifo or os.devnull
+            self._recorders[input_device] = AudioRecorder(
+                plugin=self,
+                device=device,
+                outfile=outfile,
+                duration=duration,
+                sample_rate=sample_rate,
+                dtype=dtype,
+                blocksize=blocksize,
+                latency=latency,
+                output_format=format,
+                channels=channels,
+                redis_queue=redis_queue,
+                stream=stream,
+                audio_pass_through=play_audio,
+                should_stop=self._should_stop,
+            )
+
+        return self._recorders[input_device]
+
+    def _get_input_device(self, device: Optional[str] = None) -> str:
+        return device or self.input_device or self._get_default_device('input')
+
     @action
     def record(  # pylint: disable=too-many-statements
         self,
@@ -499,121 +563,23 @@ class SoundPlugin(Plugin):
             HTTP endpoint too (default: ``/sound/stream<.format>``).
         """
 
-        self.recording_paused_changed.clear()
+        device = self._get_input_device(device)
-
+        self.create_recorder(
-        if device is None:
+            device,
-            device = self.input_device
+            output_device=output_device,
-        if device is None:
+            fifo=fifo,
-            device = self._get_default_device('input')
+            outfile=outfile,
-
+            duration=duration,
-        if play_audio:
+            sample_rate=sample_rate,
-            output_device = (
+            dtype=dtype,
-                output_device
+            blocksize=blocksize,
-                or self.output_device
+            latency=latency,
-                or self._get_default_device('output')
+            channels=channels,
-            )
+            redis_queue=redis_queue,
-
+            format=format,
-            device = (device, output_device)  # type: ignore
+            stream=stream,
-
+            play_audio=play_audio,
-        if sample_rate is None:
+        ).start()
-            dev_info = sd.query_devices(device, 'input')
-            sample_rate = int(dev_info['default_samplerate'])  # type: ignore
-
-        if blocksize is None:
-            blocksize = self.input_blocksize
-
-        if fifo:
-            fifo = os.path.expanduser(fifo)
-            if os.path.exists(fifo) and stat.S_ISFIFO(os.stat(fifo).st_mode):
-                self.logger.info('Removing previous input stream FIFO %s', fifo)
-                os.unlink(fifo)
-
-            os.mkfifo(fifo, 0o644)
-            outfile = fifo
-        elif outfile:
-            outfile = os.path.expanduser(outfile)
-
-        outfile = outfile or fifo or os.devnull
-
-        def audio_callback(audio_converter: ConverterProcess):
-            # _ = frames
-            # __ = time
-            def callback(indata, outdata, _, __, status):
-                while self._get_recording_state() == RecordingState.PAUSED:
-                    self.recording_paused_changed.wait()
-
-                if status:
-                    self.logger.warning('Recording callback status: %s', status)
-
-                audio_converter.write(indata.tobytes())
-                if play_audio:
-                    outdata[:] = indata
-
-            return callback
-
-        def streaming_thread():
-            try:
-                stream_index = self._allocate_stream_index() if play_audio else None
-
-                with ConverterProcess(
-                    ffmpeg_bin=self.ffmpeg_bin,
-                    sample_rate=sample_rate,
-                    channels=channels,
-                    dtype=dtype,
-                    chunk_size=self.input_blocksize,
-                    output_format=format,
-                ) as converter, sd.Stream(
-                    samplerate=sample_rate,
-                    device=device,
-                    channels=channels,
-                    callback=audio_callback(converter),
-                    dtype=dtype,
-                    latency=latency,
-                    blocksize=blocksize,
-                ) as audio_stream, open(
-                    outfile, 'wb'
-                ) as f:
-                    self.start_recording()
-                    if stream_index:
-                        self._start_playback(
-                            stream_index=stream_index, stream=audio_stream
-                        )
-
-                    get_bus().post(SoundRecordingStartedEvent())
-                    self.logger.info('Started recording from device [%s]', device)
-                    recording_started_time = time.time()
-
-                    while self._get_recording_state() != RecordingState.STOPPED and (
-                        duration is None
-                        or time.time() - recording_started_time < duration
-                    ):
-                        while self._get_recording_state() == RecordingState.PAUSED:
-                            self.recording_paused_changed.wait()
-
-                        timeout = (
-                            max(
-                                0,
-                                duration - (time.time() - recording_started_time),
-                            )
-                            if duration is not None
-                            else 1
-                        )
-
-                        data = converter.read(timeout=timeout)
-                        if not data:
-                            continue
-
-                        f.write(data)
-                        if redis_queue and stream:
-                            get_redis().publish(redis_queue, data)
-
-            except queue.Empty:
-                self.logger.warning('Recording timeout: audio callback failed?')
-            finally:
-                self.stop_recording()
-                get_bus().post(SoundRecordingStoppedEvent())
-
-        Thread(target=streaming_thread).start()
 
     @action
     def recordplay(self, *args, **kwargs):
@@ -626,6 +592,7 @@ class SoundPlugin(Plugin):
             stacklevel=1,
         )
 
+        kwargs['play_audio'] = True
         return self.record(*args, **kwargs)
 
     @action
@@ -718,9 +685,9 @@ class SoundPlugin(Plugin):
 
         return stream_index
 
-    def _start_playback(self, stream_index, stream):
+    def start_playback(self, stream_index, stream):
         with self.playback_state_lock:
-            self.playback_state[stream_index] = PlaybackState.PLAYING
+            self.playback_state[stream_index] = AudioState.RUNNING
             self.active_streams[stream_index] = stream
 
             if isinstance(self.playback_paused_changed.get(stream_index), Event):
@@ -756,7 +723,7 @@ class SoundPlugin(Plugin):
 
                 if self.completed_callback_events[i]:
                     completed_callback_events[i] = self.completed_callback_events[i]
-                self.playback_state[i] = PlaybackState.STOPPED
+                self.playback_state[i] = AudioState.STOPPED
 
         for i, event in completed_callback_events.items():
             event.wait()
@@ -800,10 +767,10 @@ class SoundPlugin(Plugin):
                     self.logger.info('No such stream index or name: %d', i)
                     continue
 
-                if self.playback_state[i] == PlaybackState.PAUSED:
+                if self.playback_state[i] == AudioState.PAUSED:
-                    self.playback_state[i] = PlaybackState.PLAYING
+                    self.playback_state[i] = AudioState.RUNNING
-                elif self.playback_state[i] == PlaybackState.PLAYING:
+                elif self.playback_state[i] == AudioState.RUNNING:
-                    self.playback_state[i] = PlaybackState.PAUSED
+                    self.playback_state[i] = AudioState.PAUSED
                 else:
                     continue
 
@@ -814,28 +781,41 @@ class SoundPlugin(Plugin):
             ', '.join([str(stream) for stream in streams]),
         )
 
-    def start_recording(self):
-        with self.recording_state_lock:
-            self.recording_state = RecordingState.RECORDING
-
     @action
-    def stop_recording(self):
+    def stop_recording(
-        with self.recording_state_lock:
+        self, device: Optional[str] = None, timeout: Optional[float] = 2
-            self.recording_state = RecordingState.STOPPED
+    ):
-        self.logger.info('Recording stopped')
+        """
-
+        Stop the current recording process on the selected device (default:
-    @action
+        default input device), if it is running.
-    def pause_recording(self):
+        """
-        with self.recording_state_lock:
+        device = self._get_input_device(device)
-            if self.recording_state == RecordingState.PAUSED:
+        with self._recorder_locks[device]:
-                self.recording_state = RecordingState.RECORDING
+            recorder = self._recorders.pop(device, None)
-            elif self.recording_state == RecordingState.RECORDING:
+            if not recorder:
-                self.recording_state = RecordingState.PAUSED
+                self.logger.warning('No active recording session for device %s', device)
-            else:
                 return
 
-        self.logger.info('Recording paused state toggled')
+            recorder.notify_stop()
-        self.recording_paused_changed.set()
+            recorder.join(timeout=timeout)
+
+    @action
+    def pause_recording(self, device: Optional[str] = None):
+        """
+        Toggle the recording pause state on the selected device (default:
+        default input device), if it is running.
+
+        If paused, the recording will be resumed. If running, it will be
+        paused. Otherwise, no action will be taken.
+        """
+        device = self._get_input_device(device)
+        with self._recorder_locks[device]:
+            recorder = self._recorders.get(device)
+            if not recorder:
+                self.logger.warning('No active recording session for device %s', device)
+                return
+
+            recorder.notify_pause()
 
     @action
     def release(
@@ -905,9 +885,17 @@ class SoundPlugin(Plugin):
         with self.playback_state_lock:
             return self.playback_state[stream_index]
 
-    def _get_recording_state(self):
+    @override
-        with self.recording_state_lock:
+    def main(self):
-            return self.recording_state
+        self.wait_stop()
+
+    @override
+    def stop(self):
+        super().stop()
+        devices = list(self._recorders.keys())
+
+        for device in devices:
+            self.stop_recording(device, timeout=0)
 
 
 # vim:sw=4:ts=4:et:

platypush/plugins/sound/_controllers/__init__.py

@@ -0,0 +1,5 @@
+from ._base import AudioThread
+from ._recorder import AudioRecorder
+
+
+__all__ = ['AudioRecorder', 'AudioThread']

platypush/plugins/sound/_controllers/_base.py

@@ -0,0 +1,227 @@
+from contextlib import contextmanager
+import queue
+import time
+
+from abc import ABC, abstractmethod
+from logging import getLogger
+from threading import Event, RLock, Thread
+from typing import IO, Generator, Optional, Tuple, Union
+from typing_extensions import override
+
+import sounddevice as sd
+
+from .._converter import ConverterProcess
+from .._model import AudioState
+
+
+class AudioThread(Thread, ABC):
+    """
+    Base class for audio play/record threads.
+    """
+
+    _STREAM_NAME_PREFIX = 'platypush-stream-'
+
+    def __init__(
+        self,
+        plugin,
+        device: Union[str, Tuple[str, str]],
+        outfile: str,
+        output_format: str,
+        channels: int,
+        sample_rate: int,
+        dtype: str,
+        stream: bool,
+        audio_pass_through: bool,
+        duration: Optional[float] = None,
+        blocksize: Optional[int] = None,
+        latency: Union[float, str] = 'high',
+        redis_queue: Optional[str] = None,
+        should_stop: Optional[Event] = None,
+        **kwargs,
+    ):
+        from .. import SoundPlugin
+
+        super().__init__(**kwargs)
+
+        self.plugin: SoundPlugin = plugin
+        self.device = device
+        self.outfile = outfile
+        self.output_format = output_format
+        self.channels = channels
+        self.sample_rate = sample_rate
+        self.dtype = dtype
+        self.stream = stream
+        self.duration = duration
+        self.blocksize = blocksize
+        self.latency = latency
+        self.redis_queue = redis_queue
+        self.audio_pass_through = audio_pass_through
+        self.logger = getLogger(__name__)
+
+        self._state = AudioState.STOPPED
+        self._state_lock = RLock()
+        self._started_time: Optional[float] = None
+        self._converter: Optional[ConverterProcess] = None
+        self._should_stop = should_stop or Event()
+        self.paused_changed = Event()
+
+    @property
+    def should_stop(self) -> bool:
+        """
+        Proxy for `._should_stop.is_set()`.
+        """
+        return self._should_stop.is_set()
+
+    @abstractmethod
+    def _audio_callback(self, audio_converter: ConverterProcess):
+        """
+        Returns a callback to handle the raw frames captures from the audio device.
+        """
+        raise NotImplementedError()
+
+    @abstractmethod
+    def _on_audio_converted(self, data: bytes, out_f: IO):
+        """
+        This callback will be called when the audio data has been converted.
+        """
+        raise NotImplementedError()
+
+    def main(
+        self,
+        converter: ConverterProcess,
+        audio_stream: sd.Stream,
+        out_stream_index: Optional[int],
+        out_f: IO,
+    ):
+        """
+        Main loop.
+        """
+        self.notify_start()
+        if out_stream_index:
+            self.plugin.start_playback(
+                stream_index=out_stream_index, stream=audio_stream
+            )
+
+        self.logger.info(
+            'Started %s on device [%s]', self.__class__.__name__, self.device
+        )
+        self._started_time = time.time()
+
+        while (
+            self.state != AudioState.STOPPED
+            and not self.should_stop
+            and (
+                self.duration is None
+                or time.time() - self._started_time < self.duration
+            )
+        ):
+            while self.state == AudioState.PAUSED:
+                self.paused_changed.wait()
+
+            if self.should_stop:
+                break
+
+            timeout = (
+                max(
+                    0,
+                    self.duration - (time.time() - self._started_time),
+                )
+                if self.duration is not None
+                else 1
+            )
+
+            data = converter.read(timeout=timeout)
+            if not data:
+                continue
+
+            self._on_audio_converted(data, out_f)
+
+    @override
+    def run(self):
+        super().run()
+        self.paused_changed.clear()
+
+        try:
+            stream_index = (
+                self.plugin._allocate_stream_index()  # pylint: disable=protected-access
+                if self.audio_pass_through
+                else None
+            )
+
+            with self.open_converter() as converter, sd.Stream(
+                samplerate=self.sample_rate,
+                device=self.device,
+                channels=self.channels,
+                callback=self._audio_callback(converter),
+                dtype=self.dtype,
+                latency=self.latency,
+                blocksize=self.blocksize,
+            ) as audio_stream, open(self.outfile, 'wb') as f:
+                self.main(
+                    out_stream_index=stream_index,
+                    converter=converter,
+                    audio_stream=audio_stream,
+                    out_f=f,
+                )
+        except queue.Empty:
+            self.logger.warning(
+                'Audio callback timeout for %s', self.__class__.__name__
+            )
+        finally:
+            self.notify_stop()
+
+    @contextmanager
+    def open_converter(self) -> Generator[ConverterProcess, None, None]:
+        assert not self._converter, 'A converter process is already running'
+        self._converter = ConverterProcess(
+            ffmpeg_bin=self.plugin.ffmpeg_bin,
+            sample_rate=self.sample_rate,
+            channels=self.channels,
+            dtype=self.dtype,
+            chunk_size=self.plugin.input_blocksize,
+            output_format=self.output_format,
+        )
+
+        self._converter.start()
+        yield self._converter
+
+        self._converter.stop()
+        self._converter.join(timeout=2)
+        self._converter = None
+
+    def notify_start(self):
+        self.state = AudioState.RUNNING
+
+    def notify_stop(self):
+        self.state = AudioState.STOPPED
+        if self._converter:
+            self._converter.stop()
+
+    def notify_pause(self):
+        states = {
+            AudioState.PAUSED: AudioState.RUNNING,
+            AudioState.RUNNING: AudioState.PAUSED,
+        }
+
+        with self._state_lock:
+            new_state = states.get(self.state)
+            if new_state:
+                self.state = new_state
+            else:
+                return
+
+        self.logger.info('Paused state toggled for %s', self.__class__.__name__)
+        self.paused_changed.set()
+
+    @property
+    def state(self):
+        with self._state_lock:
+            return self._state
+
+    @state.setter
+    def state(self, value: AudioState):
+        with self._state_lock:
+            self._state = value
+
+
+# vim:sw=4:ts=4:et:

platypush/plugins/sound/_controllers/_recorder.py

@@ -0,0 +1,70 @@
+from dataclasses import dataclass
+
+from typing import IO
+from typing_extensions import override
+
+from platypush.context import get_bus
+from platypush.message.event.sound import (
+    SoundRecordingStartedEvent,
+    SoundRecordingStoppedEvent,
+)
+
+from platypush.utils import get_redis
+
+from .._converter import ConverterProcess
+from .._model import AudioState
+from ._base import AudioThread
+
+
+@dataclass
+class AudioRecorder(AudioThread):
+    """
+    The ``AudioRecorder`` thread is responsible for recording audio from the
+    input device, writing it to the converter process and dispatch the
+    converted audio to the registered consumers.
+    """
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+
+    @override
+    def _audio_callback(self, audio_converter: ConverterProcess):
+        # _ = frames
+        # __ = time
+        def callback(indata, outdata, _, __, status):
+            if self.state == AudioState.PAUSED:
+                return
+
+            if status:
+                self.logger.warning('Recording callback status: %s', status)
+
+            try:
+                audio_converter.write(indata.tobytes())
+            except AssertionError as e:
+                self.logger.warning('Audio recorder callback error: %s', e)
+                self.state = AudioState.STOPPED
+                return
+
+            if self.audio_pass_through:
+                outdata[:] = indata
+
+        return callback
+
+    @override
+    def _on_audio_converted(self, data: bytes, out_f: IO):
+        out_f.write(data)
+        if self.redis_queue and self.stream:
+            get_redis().publish(self.redis_queue, data)
+
+    @override
+    def notify_start(self):
+        super().notify_start()
+        get_bus().post(SoundRecordingStartedEvent())
+
+    @override
+    def notify_stop(self):
+        super().notify_stop()
+        get_bus().post(SoundRecordingStoppedEvent())
+
+
+# vim:sw=4:ts=4:et:

platypush/plugins/sound/_converter.py

@@ -3,7 +3,7 @@ from asyncio.subprocess import PIPE
 from queue import Empty
 
 from queue import Queue
-from threading import Thread
+from threading import Event, RLock, Thread
 from typing import Optional, Self
 
 from platypush.context import get_or_create_event_loop
@@ -75,19 +75,15 @@ class ConverterProcess(Thread):
         self._out_queue = Queue()
         self.ffmpeg = None
         self._loop = None
+        self._should_stop = Event()
+        self._stop_lock = RLock()
 
     def __enter__(self) -> Self:
         self.start()
         return self
 
     def __exit__(self, *_, **__):
-        if self.ffmpeg and self._loop:
+        self.stop()
-            self._loop.call_soon_threadsafe(self.ffmpeg.kill)
-
-        self.ffmpeg = None
-
-        if self._loop:
-            self._loop = None
 
     def _check_ffmpeg(self):
         assert (
@@ -125,7 +121,12 @@ class ConverterProcess(Thread):
         except asyncio.TimeoutError:
             pass
 
-        while self._loop and self.ffmpeg and self.ffmpeg.returncode is None:
+        while (
+            self._loop
+            and self.ffmpeg
+            and self.ffmpeg.returncode is None
+            and not self.should_stop
+        ):
             self._check_ffmpeg()
             assert (
                 self.ffmpeg and self.ffmpeg.stdout
@@ -158,5 +159,23 @@ class ConverterProcess(Thread):
         self._loop = get_or_create_event_loop()
         self._loop.run_until_complete(self._audio_proxy(timeout=1))
 
+    def stop(self):
+        with self._stop_lock:
+            self._should_stop.set()
+            if self.ffmpeg:
+                try:
+                    self.ffmpeg.kill()
+                except ProcessLookupError:
+                    pass
+
+            self.ffmpeg = None
+
+            if self._loop:
+                self._loop = None
+
+    @property
+    def should_stop(self) -> bool:
+        return self._should_stop.is_set()
+
 
 # vim:sw=4:ts=4:et:

platypush/plugins/sound/_model.py

@@ -0,0 +1,11 @@
+from enum import Enum
+
+
+class AudioState(Enum):
+    """
+    Audio states.
+    """
+
+    STOPPED = 'STOPPED'
+    RUNNING = 'RUNNING'
+    PAUSED = 'PAUSED'