music-assistant-server

1"""Unified AirPlay/RAOP stream session logic for AirPlay devices."""
2
3from __future__ import annotations
4
5import asyncio
6import time
7from collections import deque
8from collections.abc import AsyncGenerator
9from contextlib import suppress
10from typing import TYPE_CHECKING
11
12from music_assistant_models.enums import PlaybackState
13from music_assistant_models.errors import PlayerCommandFailed
14
15from music_assistant.constants import CONF_SYNC_ADJUST
16from music_assistant.helpers.audio import get_player_filter_params
17from music_assistant.helpers.ffmpeg import FFMpeg
18from music_assistant.providers.airplay.helpers import ntp_to_unix_time, unix_time_to_ntp
19
20from .constants import (
21    AIRPLAY2_CONNECT_TIME_MS,
22    CONF_ENABLE_LATE_JOIN,
23    ENABLE_LATE_JOIN_DEFAULT,
24    RAOP_CONNECT_TIME_MS,
25    StreamingProtocol,
26)
27from .protocols.airplay2 import AirPlay2Stream
28from .protocols.raop import RaopStream
29
30if TYPE_CHECKING:
31    from music_assistant_models.media_items import AudioFormat
32
33    from .player import AirPlayPlayer
34    from .provider import AirPlayProvider
35
36
37class AirPlayStreamSession:
38    """Stream session (RAOP or AirPlay2) to one or more players."""
39
40    def __init__(
41        self,
42        airplay_provider: AirPlayProvider,
43        sync_clients: list[AirPlayPlayer],
44        pcm_format: AudioFormat,
45    ) -> None:
46        """Initialize AirPlayStreamSession.
47
48        :param airplay_provider: The AirPlay provider instance.
49        :param sync_clients: List of AirPlay players to stream to.
50        :param pcm_format: PCM format of the input stream.
51        """
52        assert sync_clients
53        self.prov = airplay_provider
54        self.mass = airplay_provider.mass
55        self.pcm_format = pcm_format
56        self.sync_clients = sync_clients
57        self._audio_source_task: asyncio.Task[None] | None = None
58        self._player_ffmpeg: dict[str, FFMpeg] = {}
59        self._lock = asyncio.Lock()
60        self.start_ntp: int = 0
61        self.start_time: float = 0.0
62        self.wait_start: float = 0.0
63        self.seconds_streamed: float = 0
64        self._first_chunk_received = asyncio.Event()
65        # Ring buffer for late joiners: stores (chunk_data, seconds_offset) tuples
66        # Chunks from streams controller are ~1 second each (pcm_sample_size bytes)
67        # Keep 8 seconds of buffer for late joiners (maxlen=10 for safety with variable sizes)
68        self._chunk_buffer: deque[tuple[bytes, float]] = deque(maxlen=10)
69
70    async def start(self, audio_source: AsyncGenerator[bytes, None]) -> None:
71        """Initialize stream session for all players."""
72        cur_time = time.time()
73        has_airplay2_client = any(
74            p.protocol == StreamingProtocol.AIRPLAY2 for p in self.sync_clients
75        )
76        wait_start = AIRPLAY2_CONNECT_TIME_MS if has_airplay2_client else RAOP_CONNECT_TIME_MS
77        wait_start_seconds = wait_start / 1000
78        self.wait_start = wait_start_seconds
79        self.start_time = cur_time + wait_start_seconds
80        self.start_ntp = unix_time_to_ntp(self.start_time)
81        await asyncio.gather(*[self._start_client(p, self.start_ntp) for p in self.sync_clients])
82        self._audio_source_task = asyncio.create_task(self._audio_streamer(audio_source))
83        try:
84            await asyncio.gather(
85                *[p.stream.wait_for_connection() for p in self.sync_clients if p.stream]
86            )
87        except Exception:
88            # playback failed to start, cleanup
89            await self.stop()
90            raise PlayerCommandFailed("Playback failed to start")
91
92    async def stop(self) -> None:
93        """Stop playback and cleanup."""
94        if self._audio_source_task and not self._audio_source_task.done():
95            self._audio_source_task.cancel()
96            with suppress(asyncio.CancelledError):
97                await self._audio_source_task
98        await asyncio.gather(
99            *[self.remove_client(x) for x in self.sync_clients],
100        )
101
102    async def remove_client(self, airplay_player: AirPlayPlayer) -> None:
103        """Remove a sync client from the session."""
104        async with self._lock:
105            if airplay_player not in self.sync_clients:
106                return
107            self.sync_clients.remove(airplay_player)
108        await self.stop_client(airplay_player)
109        airplay_player.set_state_from_stream(PlaybackState.IDLE)
110        # If this was the last client, stop the session
111        if not self.sync_clients:
112            await self.stop()
113            return
114
115    async def stop_client(self, airplay_player: AirPlayPlayer) -> None:
116        """
117        Stop a client's stream and ffmpeg.
118
119        :param airplay_player: The player to stop.
120        :param force: If True, kill CLI process immediately.
121        """
122        ffmpeg = self._player_ffmpeg.pop(airplay_player.player_id, None)
123        # note that we use kill instead of graceful close here,
124        # because otherwise it can take a very long time for the process to exit.
125        if ffmpeg and not ffmpeg.closed:
126            await ffmpeg.kill()
127        if airplay_player.stream and airplay_player.stream.session == self:
128            await airplay_player.stream.stop(force=True)
129
130    async def add_client(self, airplay_player: AirPlayPlayer) -> None:
131        """Add a sync client to the session as a late joiner.
132
133        The late joiner will:
134        1. Start with NTP timestamp accounting for buffered chunks we'll send
135        2. Receive buffered chunks immediately to prime the ffmpeg/CLI pipeline
136        3. Join the real-time stream in perfect sync with other players
137        """
138        sync_leader = self.sync_clients[0]
139        if not sync_leader.stream or not sync_leader.stream.running:
140            return
141
142        allow_late_join = self.prov.config.get_value(
143            CONF_ENABLE_LATE_JOIN, ENABLE_LATE_JOIN_DEFAULT
144        )
145        if not allow_late_join:
146            await self.stop()
147            if sync_leader.state.current_media:
148                self.mass.call_later(
149                    0.5,
150                    self.mass.players.cmd_resume(sync_leader.player_id),
151                    task_id=f"resync_session_{sync_leader.player_id}",
152                )
153            return
154
155        async with self._lock:
156            # Get all buffered chunks to send
157            buffered_chunks = list(self._chunk_buffer)
158
159            if buffered_chunks:
160                # Calculate how much buffer we're sending
161                first_chunk_position = buffered_chunks[0][1]
162                buffer_duration = self.seconds_streamed - first_chunk_position
163
164                # Set start NTP to account for the buffer we're about to send
165                # Device will start at (current_position - buffer_duration) and catch up
166                start_at = self.start_time + (self.seconds_streamed - buffer_duration)
167
168                self.prov.logger.debug(
169                    "Late joiner %s: sending %.2fs of buffered audio, start at %.2fs",
170                    airplay_player.player_id,
171                    buffer_duration,
172                    self.seconds_streamed - buffer_duration,
173                )
174            else:
175                # No buffer available, start from current position
176                start_at = self.start_time + self.seconds_streamed
177                self.prov.logger.debug(
178                    "Late joiner %s: no buffered chunks available, starting at %.2fs",
179                    airplay_player.player_id,
180                    self.seconds_streamed,
181                )
182
183            start_ntp = unix_time_to_ntp(start_at)
184
185            if airplay_player not in self.sync_clients:
186                self.sync_clients.append(airplay_player)
187
188            await self._start_client(airplay_player, start_ntp)
189            if airplay_player.stream:
190                await airplay_player.stream.wait_for_connection()
191
192            # Feed buffered chunks INSIDE the lock to prevent race conditions
193            # This ensures we don't send a new real-time chunk while feeding the buffer
194            if buffered_chunks:
195                await self._feed_buffered_chunks(airplay_player, buffered_chunks)
196
197    async def _audio_streamer(self, audio_source: AsyncGenerator[bytes, None]) -> None:
198        """Stream audio to all players."""
199        pcm_sample_size = self.pcm_format.pcm_sample_size
200        watchdog_task = asyncio.create_task(self._silence_watchdog(pcm_sample_size))
201        try:
202            async for chunk in audio_source:
203                if not self._first_chunk_received.is_set():
204                    watchdog_task.cancel()
205                    with suppress(asyncio.CancelledError):
206                        await watchdog_task
207                    self._first_chunk_received.set()
208
209                if not self.sync_clients:
210                    break
211
212                await self._write_chunk_to_all_players(chunk)
213                self.seconds_streamed += len(chunk) / pcm_sample_size
214        finally:
215            if not watchdog_task.done():
216                watchdog_task.cancel()
217                with suppress(asyncio.CancelledError):
218                    await watchdog_task
219        async with self._lock:
220            await asyncio.gather(
221                *[
222                    self._write_eof_to_player(x)
223                    for x in self.sync_clients
224                    if x.stream and x.stream.running
225                ],
226                return_exceptions=True,
227            )
228
229    async def _silence_watchdog(self, pcm_sample_size: int) -> None:
230        """Insert silence if audio source is slow to deliver first chunk."""
231        grace_period = 0.2
232        max_silence_padding = 5.0
233        silence_inserted = 0.0
234
235        await asyncio.sleep(grace_period)
236        while not self._first_chunk_received.is_set() and silence_inserted < max_silence_padding:
237            silence_duration = 0.1
238            silence_bytes = int(pcm_sample_size * silence_duration)
239            silence_chunk = bytes(silence_bytes)
240            await self._write_chunk_to_all_players(silence_chunk)
241            self.seconds_streamed += silence_duration
242            silence_inserted += silence_duration
243            await asyncio.sleep(0.05)
244
245        if silence_inserted > 0:
246            self.prov.logger.warning(
247                "Inserted %.1fs silence padding while waiting for audio source",
248                silence_inserted,
249            )
250
251    async def _write_chunk_to_all_players(self, chunk: bytes) -> None:
252        """Write a chunk to all connected players."""
253        async with self._lock:
254            sync_clients = [x for x in self.sync_clients if x.stream and x.stream.running]
255            if not sync_clients:
256                return
257
258            # Add chunk to ring buffer for late joiners (before seconds_streamed is updated)
259            chunk_position = self.seconds_streamed
260            self._chunk_buffer.append((chunk, chunk_position))
261
262            # Write chunk to all players
263            write_tasks = [self._write_chunk_to_player(x, chunk) for x in sync_clients if x.stream]
264            results = await asyncio.gather(*write_tasks, return_exceptions=True)
265
266            # Check for write errors or timeouts
267            players_to_remove: list[AirPlayPlayer] = []
268            for i, result in enumerate(results):
269                if i >= len(sync_clients):
270                    continue
271                player = sync_clients[i]
272
273                if isinstance(result, TimeoutError):
274                    self.prov.logger.warning(
275                        "Removing player %s from session: stopped reading data (write timeout)",
276                        player.player_id,
277                    )
278                    players_to_remove.append(player)
279                elif isinstance(result, Exception):
280                    self.prov.logger.warning(
281                        "Removing player %s from session due to write error: %s",
282                        player.player_id,
283                        result,
284                    )
285                    players_to_remove.append(player)
286
287            for player in players_to_remove:
288                self.mass.create_task(self.remove_client(player))
289
290    async def _write_chunk_to_player(self, airplay_player: AirPlayPlayer, chunk: bytes) -> None:
291        """Write audio chunk to a player's ffmpeg process."""
292        player_id = airplay_player.player_id
293        if ffmpeg := self._player_ffmpeg.get(player_id):
294            if ffmpeg.closed:
295                return
296            await asyncio.wait_for(ffmpeg.write(chunk), timeout=35.0)
297
298    async def _feed_buffered_chunks(
299        self,
300        airplay_player: AirPlayPlayer,
301        buffered_chunks: list[tuple[bytes, float]],
302    ) -> None:
303        """Feed buffered chunks to a late joiner to prime the ffmpeg pipeline.
304
305        :param airplay_player: The late joiner player.
306        :param buffered_chunks: List of (chunk_data, position) tuples to send.
307        """
308        try:
309            for chunk, _position in buffered_chunks:
310                await self._write_chunk_to_player(airplay_player, chunk)
311        except Exception as err:
312            self.prov.logger.warning(
313                "Failed to feed buffered chunks to late joiner %s: %s",
314                airplay_player.player_id,
315                err,
316            )
317            # Remove the client if feeding buffered chunks fails
318            self.mass.create_task(self.remove_client(airplay_player))
319
320    async def _write_eof_to_player(self, airplay_player: AirPlayPlayer) -> None:
321        """Write EOF to a specific player."""
322        if ffmpeg := self._player_ffmpeg.pop(airplay_player.player_id, None):
323            await ffmpeg.write_eof()
324            await ffmpeg.wait_with_timeout(30)
325            if airplay_player.stream and airplay_player.stream._cli_proc:
326                await airplay_player.stream._cli_proc.write_eof()
327
328    async def _start_client(self, airplay_player: AirPlayPlayer, start_ntp: int) -> None:
329        """Start CLI process and ffmpeg for a single client."""
330        if airplay_player.stream and airplay_player.stream.running:
331            await airplay_player.stream.stop()
332        if airplay_player.protocol == StreamingProtocol.AIRPLAY2:
333            airplay_player.stream = AirPlay2Stream(airplay_player)
334        else:
335            airplay_player.stream = RaopStream(airplay_player)
336        airplay_player.stream.session = self
337        sync_adjust = airplay_player.config.get_value(CONF_SYNC_ADJUST, 0)
338        assert isinstance(sync_adjust, int)
339        if sync_adjust != 0:
340            start_ntp = unix_time_to_ntp(ntp_to_unix_time(start_ntp) + (sync_adjust / 1000))
341        await airplay_player.stream.start(start_ntp)
342        # Start ffmpeg to feed audio to CLI stdin
343        if ffmpeg := self._player_ffmpeg.pop(airplay_player.player_id, None):
344            await ffmpeg.close()
345        filter_params = get_player_filter_params(
346            self.mass,
347            airplay_player.player_id,
348            self.pcm_format,
349            airplay_player.stream.pcm_format,
350        )
351        cli_proc = airplay_player.stream._cli_proc
352        assert cli_proc
353        assert cli_proc.proc
354        assert cli_proc.proc.stdin
355        stdin_transport = cli_proc.proc.stdin.transport
356        audio_output: str | int = stdin_transport.get_extra_info("pipe").fileno()
357        ffmpeg = FFMpeg(
358            audio_input="-",
359            input_format=self.pcm_format,
360            output_format=airplay_player.stream.pcm_format,
361            filter_params=filter_params,
362            audio_output=audio_output,
363        )
364        await ffmpeg.start()
365        self._player_ffmpeg[airplay_player.player_id] = ffmpeg
366