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 buffered chunks to send, but limit to ~5 seconds to avoid
157            # blocking real-time streaming to other players (causes packet loss)
158            max_late_join_buffer_seconds = 5.0
159            all_buffered = list(self._chunk_buffer)
160
161            # Filter to only include chunks within the time limit
162            if all_buffered:
163                min_position = self.seconds_streamed - max_late_join_buffer_seconds
164                buffered_chunks = [
165                    (chunk, pos) for chunk, pos in all_buffered if pos >= min_position
166                ]
167            else:
168                buffered_chunks = []
169
170            if buffered_chunks:
171                # Calculate how much buffer we're sending
172                first_chunk_position = buffered_chunks[0][1]
173                buffer_duration = self.seconds_streamed - first_chunk_position
174
175                # Set start NTP to account for the buffer we're about to send
176                # Device will start at (current_position - buffer_duration) and catch up
177                start_at = self.start_time + (self.seconds_streamed - buffer_duration)
178
179                self.prov.logger.debug(
180                    "Late joiner %s: sending %.2fs of buffered audio, start at %.2fs",
181                    airplay_player.player_id,
182                    buffer_duration,
183                    self.seconds_streamed - buffer_duration,
184                )
185            else:
186                # No buffer available, start from current position
187                start_at = self.start_time + self.seconds_streamed
188                self.prov.logger.debug(
189                    "Late joiner %s: no buffered chunks available, starting at %.2fs",
190                    airplay_player.player_id,
191                    self.seconds_streamed,
192                )
193
194            start_ntp = unix_time_to_ntp(start_at)
195
196            if airplay_player not in self.sync_clients:
197                self.sync_clients.append(airplay_player)
198
199            await self._start_client(airplay_player, start_ntp)
200            if airplay_player.stream:
201                await airplay_player.stream.wait_for_connection()
202
203            # Feed buffered chunks INSIDE the lock to prevent race conditions
204            # This ensures we don't send a new real-time chunk while feeding the buffer
205            if buffered_chunks:
206                await self._feed_buffered_chunks(airplay_player, buffered_chunks)
207
208    async def _audio_streamer(self, audio_source: AsyncGenerator[bytes, None]) -> None:
209        """Stream audio to all players."""
210        pcm_sample_size = self.pcm_format.pcm_sample_size
211        watchdog_task = asyncio.create_task(self._silence_watchdog(pcm_sample_size))
212        try:
213            async for chunk in audio_source:
214                if not self._first_chunk_received.is_set():
215                    watchdog_task.cancel()
216                    with suppress(asyncio.CancelledError):
217                        await watchdog_task
218                    self._first_chunk_received.set()
219
220                if not self.sync_clients:
221                    break
222
223                has_running_clients = await self._write_chunk_to_all_players(chunk)
224                if not has_running_clients:
225                    self.prov.logger.debug("No running clients remaining, stopping audio streamer")
226                    break
227                self.seconds_streamed += len(chunk) / pcm_sample_size
228        finally:
229            if not watchdog_task.done():
230                watchdog_task.cancel()
231                with suppress(asyncio.CancelledError):
232                    await watchdog_task
233        async with self._lock:
234            await asyncio.gather(
235                *[
236                    self._write_eof_to_player(x)
237                    for x in self.sync_clients
238                    if x.stream and x.stream.running
239                ],
240                return_exceptions=True,
241            )
242
243    async def _silence_watchdog(self, pcm_sample_size: int) -> None:
244        """Insert silence if audio source is slow to deliver first chunk."""
245        grace_period = 0.2
246        max_silence_padding = 5.0
247        silence_inserted = 0.0
248
249        await asyncio.sleep(grace_period)
250        while not self._first_chunk_received.is_set() and silence_inserted < max_silence_padding:
251            silence_duration = 0.1
252            silence_bytes = int(pcm_sample_size * silence_duration)
253            silence_chunk = bytes(silence_bytes)
254            has_running_clients = await self._write_chunk_to_all_players(silence_chunk)
255            if not has_running_clients:
256                break
257            self.seconds_streamed += silence_duration
258            silence_inserted += silence_duration
259            await asyncio.sleep(0.05)
260
261        if silence_inserted > 0:
262            self.prov.logger.warning(
263                "Inserted %.1fs silence padding while waiting for audio source",
264                silence_inserted,
265            )
266
267    async def _write_chunk_to_all_players(self, chunk: bytes) -> bool:
268        """Write a chunk to all connected players.
269
270        :return: True if there are still running clients, False otherwise.
271        """
272        async with self._lock:
273            sync_clients = [x for x in self.sync_clients if x.stream and x.stream.running]
274            if not sync_clients:
275                return False
276
277            # Add chunk to ring buffer for late joiners (before seconds_streamed is updated)
278            chunk_position = self.seconds_streamed
279            self._chunk_buffer.append((chunk, chunk_position))
280
281            # Write chunk to all players
282            write_tasks = [self._write_chunk_to_player(x, chunk) for x in sync_clients if x.stream]
283            results = await asyncio.gather(*write_tasks, return_exceptions=True)
284
285            # Check for write errors or timeouts
286            players_to_remove: list[AirPlayPlayer] = []
287            for i, result in enumerate(results):
288                if i >= len(sync_clients):
289                    continue
290                player = sync_clients[i]
291
292                if isinstance(result, TimeoutError):
293                    self.prov.logger.warning(
294                        "Removing player %s from session: stopped reading data (write timeout)",
295                        player.player_id,
296                    )
297                    players_to_remove.append(player)
298                elif isinstance(result, Exception):
299                    self.prov.logger.warning(
300                        "Removing player %s from session due to write error: %s",
301                        player.player_id,
302                        result,
303                    )
304                    players_to_remove.append(player)
305
306            for player in players_to_remove:
307                self.mass.create_task(self.remove_client(player))
308
309            # Return False if all clients were removed (or scheduled for removal)
310            remaining_clients = len(sync_clients) - len(players_to_remove)
311            return remaining_clients > 0
312
313    async def _write_chunk_to_player(self, airplay_player: AirPlayPlayer, chunk: bytes) -> None:
314        """Write audio chunk to a player's ffmpeg process."""
315        player_id = airplay_player.player_id
316        if ffmpeg := self._player_ffmpeg.get(player_id):
317            if ffmpeg.closed:
318                return
319            await asyncio.wait_for(ffmpeg.write(chunk), timeout=35.0)
320
321    async def _feed_buffered_chunks(
322        self,
323        airplay_player: AirPlayPlayer,
324        buffered_chunks: list[tuple[bytes, float]],
325    ) -> None:
326        """Feed buffered chunks to a late joiner to prime the ffmpeg pipeline.
327
328        :param airplay_player: The late joiner player.
329        :param buffered_chunks: List of (chunk_data, position) tuples to send.
330        """
331        try:
332            for chunk, _position in buffered_chunks:
333                await self._write_chunk_to_player(airplay_player, chunk)
334        except Exception as err:
335            self.prov.logger.warning(
336                "Failed to feed buffered chunks to late joiner %s: %s",
337                airplay_player.player_id,
338                err,
339            )
340            # Remove the client if feeding buffered chunks fails
341            self.mass.create_task(self.remove_client(airplay_player))
342
343    async def _write_eof_to_player(self, airplay_player: AirPlayPlayer) -> None:
344        """Write EOF to a specific player."""
345        if ffmpeg := self._player_ffmpeg.pop(airplay_player.player_id, None):
346            await ffmpeg.write_eof()
347            await ffmpeg.wait_with_timeout(30)
348            if airplay_player.stream and airplay_player.stream._cli_proc:
349                await airplay_player.stream._cli_proc.write_eof()
350
351    async def _start_client(self, airplay_player: AirPlayPlayer, start_ntp: int) -> None:
352        """Start CLI process and ffmpeg for a single client."""
353        if airplay_player.stream and airplay_player.stream.running:
354            await airplay_player.stream.stop()
355        if airplay_player.protocol == StreamingProtocol.AIRPLAY2:
356            airplay_player.stream = AirPlay2Stream(airplay_player)
357        else:
358            airplay_player.stream = RaopStream(airplay_player)
359        airplay_player.stream.session = self
360        sync_adjust = airplay_player.config.get_value(CONF_SYNC_ADJUST, 0)
361        assert isinstance(sync_adjust, int)
362        if sync_adjust != 0:
363            start_ntp = unix_time_to_ntp(ntp_to_unix_time(start_ntp) + (sync_adjust / 1000))
364        await airplay_player.stream.start(start_ntp)
365        # Start ffmpeg to feed audio to CLI stdin
366        if ffmpeg := self._player_ffmpeg.pop(airplay_player.player_id, None):
367            await ffmpeg.close()
368        filter_params = get_player_filter_params(
369            self.mass,
370            airplay_player.player_id,
371            self.pcm_format,
372            airplay_player.stream.pcm_format,
373        )
374        cli_proc = airplay_player.stream._cli_proc
375        assert cli_proc
376        assert cli_proc.proc
377        assert cli_proc.proc.stdin
378        stdin_transport = cli_proc.proc.stdin.transport
379        audio_output: str | int = stdin_transport.get_extra_info("pipe").fileno()
380        ffmpeg = FFMpeg(
381            audio_input="-",
382            input_format=self.pcm_format,
383            output_format=airplay_player.stream.pcm_format,
384            filter_params=filter_params,
385            audio_output=audio_output,
386        )
387        await ffmpeg.start()
388        self._player_ffmpeg[airplay_player.player_id] = ffmpeg
389