Source code for mopidy.audio.actor

import logging
import os
import threading

import pykka

from mopidy import exceptions
from mopidy.audio import tags as tags_lib
from mopidy.audio import utils
from mopidy.audio.constants import PlaybackState
from mopidy.audio.listener import AudioListener
from mopidy.internal import process
from mopidy.internal.gi import GLib, GObject, Gst, GstPbutils

logger = logging.getLogger(__name__)

# This logger is only meant for debug logging of low level GStreamer info such
# as callbacks, event, messages and direct interaction with GStreamer such as
# set_state() on a pipeline.
gst_logger = logging.getLogger("mopidy.audio.gst")

_GST_PLAY_FLAGS_AUDIO = 0x02
_GST_PLAY_FLAGS_DOWNLOAD = 0x80

_GST_STATE_MAPPING = {
    Gst.State.PLAYING: PlaybackState.PLAYING,
    Gst.State.PAUSED: PlaybackState.PAUSED,
    Gst.State.NULL: PlaybackState.STOPPED,
}


# TODO: expose this as a property on audio?
class _Appsrc:

    """Helper class for dealing with appsrc based playback."""

    def __init__(self):
        self._signals = utils.Signals()
        self.reset()

    def reset(self):
        """Reset the helper.

        Should be called whenever the source changes and we are not setting up
        a new appsrc.
        """
        self.prepare(None, None, None, None)

    def prepare(self, caps, need_data, enough_data, seek_data):
        """Store info we will need when the appsrc element gets installed."""
        self._signals.clear()
        self._source = None
        self._caps = caps
        self._need_data_callback = need_data
        self._seek_data_callback = seek_data
        self._enough_data_callback = enough_data

    def configure(self, source):
        """Configure the supplied source for use.

        Should be called whenever we get a new appsrc.
        """
        source.set_property("caps", self._caps)
        source.set_property("format", "time")
        source.set_property("stream-type", "seekable")
        source.set_property("max-bytes", 1 << 20)  # 1MB
        source.set_property("min-percent", 50)

        if self._need_data_callback:
            self._signals.connect(
                source, "need-data", self._on_signal, self._need_data_callback
            )
        if self._seek_data_callback:
            self._signals.connect(
                source, "seek-data", self._on_signal, self._seek_data_callback
            )
        if self._enough_data_callback:
            self._signals.connect(
                source,
                "enough-data",
                self._on_signal,
                None,
                self._enough_data_callback,
            )

        self._source = source

    def push(self, buffer_):
        if self._source is None:
            return False

        if buffer_ is None:
            gst_logger.debug("Sending appsrc end-of-stream event.")
            result = self._source.emit("end-of-stream")
            return result == Gst.FlowReturn.OK
        else:
            result = self._source.emit("push-buffer", buffer_)
            return result == Gst.FlowReturn.OK

    def _on_signal(self, element, clocktime, func):
        # This shim is used to ensure we always return true, and also handles
        # that not all the callbacks have a time argument.
        if clocktime is None:
            func()
        else:
            func(utils.clocktime_to_millisecond(clocktime))
        return True


# TODO: expose this as a property on audio when #790 gets further along.
class _Outputs(Gst.Bin):
    def __init__(self):
        Gst.Bin.__init__(self)
        # TODO gst1: Set 'outputs' as the Bin name for easier debugging

        self._tee = Gst.ElementFactory.make("tee")
        self.add(self._tee)

        ghost_pad = Gst.GhostPad.new("sink", self._tee.get_static_pad("sink"))
        self.add_pad(ghost_pad)

    def add_output(self, description):
        # XXX This only works for pipelines not in use until #790 gets done.
        try:
            output = Gst.parse_bin_from_description(
                description, ghost_unlinked_pads=True
            )
        except GLib.GError as ex:
            logger.error(
                'Failed to create audio output "%s": %s', description, ex
            )
            raise exceptions.AudioException(ex)

        self._add(output)
        logger.info('Audio output set to "%s"', description)

    def _add(self, element):
        queue = Gst.ElementFactory.make("queue")
        self.add(element)
        self.add(queue)
        queue.link(element)
        self._tee.link(queue)


class SoftwareMixer:
    def __init__(self, mixer):
        self._mixer = mixer
        self._element = None
        self._last_volume = None
        self._last_mute = None
        self._signals = utils.Signals()

    def setup(self, element, mixer_ref):
        self._element = element
        self._mixer.setup(mixer_ref)

    def teardown(self):
        self._signals.clear()
        self._mixer.teardown()

    def get_volume(self):
        return int(round(self._element.get_property("volume") * 100))

    def set_volume(self, volume):
        self._element.set_property("volume", volume / 100.0)
        self._mixer.trigger_volume_changed(self.get_volume())

    def get_mute(self):
        return self._element.get_property("mute")

    def set_mute(self, mute):
        self._element.set_property("mute", bool(mute))
        self._mixer.trigger_mute_changed(self.get_mute())


class _Handler:
    def __init__(self, audio):
        self._audio = audio
        self._element = None
        self._pad = None
        self._message_handler_id = None
        self._event_handler_id = None

    def setup_message_handling(self, element):
        self._element = element
        bus = element.get_bus()
        bus.add_signal_watch()
        self._message_handler_id = bus.connect("message", self.on_message)

    def setup_event_handling(self, pad):
        self._pad = pad
        self._event_handler_id = pad.add_probe(
            Gst.PadProbeType.EVENT_BOTH, self.on_pad_event
        )

    def teardown_message_handling(self):
        bus = self._element.get_bus()
        bus.remove_signal_watch()
        bus.disconnect(self._message_handler_id)
        self._message_handler_id = None

    def teardown_event_handling(self):
        self._pad.remove_probe(self._event_handler_id)
        self._event_handler_id = None

    def on_message(self, bus, msg):
        if msg.type == Gst.MessageType.STATE_CHANGED:
            if msg.src != self._element:
                return
            old_state, new_state, pending_state = msg.parse_state_changed()
            self.on_playbin_state_changed(old_state, new_state, pending_state)
        elif msg.type == Gst.MessageType.BUFFERING:
            self.on_buffering(msg.parse_buffering(), msg.get_structure())
        elif msg.type == Gst.MessageType.EOS:
            self.on_end_of_stream()
        elif msg.type == Gst.MessageType.ERROR:
            error, debug = msg.parse_error()
            self.on_error(error, debug)
        elif msg.type == Gst.MessageType.WARNING:
            error, debug = msg.parse_warning()
            self.on_warning(error, debug)
        elif msg.type == Gst.MessageType.ASYNC_DONE:
            self.on_async_done()
        elif msg.type == Gst.MessageType.TAG:
            taglist = msg.parse_tag()
            self.on_tag(taglist)
        elif msg.type == Gst.MessageType.ELEMENT:
            if GstPbutils.is_missing_plugin_message(msg):
                self.on_missing_plugin(msg)
        elif msg.type == Gst.MessageType.STREAM_START:
            self.on_stream_start()

    def on_pad_event(self, pad, pad_probe_info):
        event = pad_probe_info.get_event()
        if event.type == Gst.EventType.SEGMENT:
            self.on_segment(event.parse_segment())
        return Gst.PadProbeReturn.OK

    def on_playbin_state_changed(self, old_state, new_state, pending_state):
        gst_logger.debug(
            "Got STATE_CHANGED bus message: old=%s new=%s pending=%s",
            old_state.value_name,
            new_state.value_name,
            pending_state.value_name,
        )

        if new_state == Gst.State.READY and pending_state == Gst.State.NULL:
            # XXX: We're not called on the last state change when going down to
            # NULL, so we rewrite the second to last call to get the expected
            # behavior.
            new_state = Gst.State.NULL
            pending_state = Gst.State.VOID_PENDING

        if pending_state != Gst.State.VOID_PENDING:
            return  # Ignore intermediate state changes

        if new_state == Gst.State.READY:
            return  # Ignore READY state as it's GStreamer specific

        new_state = _GST_STATE_MAPPING[new_state]
        old_state, self._audio.state = self._audio.state, new_state

        target_state = _GST_STATE_MAPPING.get(self._audio._target_state)
        if target_state is None:
            # XXX: Workaround for #1430, to be fixed properly by #1222.
            logger.warning("Race condition happened. See #1222 and #1430.")
            return
        if target_state == new_state:
            target_state = None

        logger.debug(
            "Audio event: state_changed(old_state=%s, new_state=%s, "
            "target_state=%s)",
            old_state,
            new_state,
            target_state,
        )
        AudioListener.send(
            "state_changed",
            old_state=old_state,
            new_state=new_state,
            target_state=target_state,
        )
        if new_state == PlaybackState.STOPPED:
            logger.debug("Audio event: stream_changed(uri=None)")
            AudioListener.send("stream_changed", uri=None)

        if "GST_DEBUG_DUMP_DOT_DIR" in os.environ:
            Gst.debug_bin_to_dot_file(
                self._audio._playbin, Gst.DebugGraphDetails.ALL, "mopidy"
            )

    def on_buffering(self, percent, structure=None):
        if self._audio._target_state < Gst.State.PAUSED:
            gst_logger.debug("Skip buffering during track change.")
            return

        if structure is not None and structure.has_field("buffering-mode"):
            buffering_mode = structure.get_enum(
                "buffering-mode", Gst.BufferingMode
            )
            if buffering_mode == Gst.BufferingMode.LIVE:
                return  # Live sources stall in paused.

        level = logging.getLevelName("TRACE")
        if percent < 10 and not self._audio._buffering:
            self._audio._playbin.set_state(Gst.State.PAUSED)
            self._audio._buffering = True
            level = logging.DEBUG
        if percent == 100:
            self._audio._buffering = False
            if self._audio._target_state == Gst.State.PLAYING:
                self._audio._playbin.set_state(Gst.State.PLAYING)
            level = logging.DEBUG

        gst_logger.log(
            level, "Got BUFFERING bus message: percent=%d%%", percent
        )

    def on_end_of_stream(self):
        gst_logger.debug("Got EOS (end of stream) bus message.")
        logger.debug("Audio event: reached_end_of_stream()")
        self._audio._tags = {}
        AudioListener.send("reached_end_of_stream")

    def on_error(self, error, debug):
        gst_logger.error(f"GStreamer error: {error.message}")
        gst_logger.debug(
            f"Got ERROR bus message: error={error!r} debug={debug!r}"
        )

        # TODO: is this needed?
        self._audio.stop_playback()

    def on_warning(self, error, debug):
        gst_logger.warning(f"GStreamer warning: {error.message}")
        gst_logger.debug(
            f"Got WARNING bus message: error={error!r} debug={debug!r}"
        )

    def on_async_done(self):
        gst_logger.debug("Got ASYNC_DONE bus message.")

    def on_tag(self, taglist):
        tags = tags_lib.convert_taglist(taglist)
        gst_logger.debug(
            f"Got TAG bus message: tags={tags_lib.repr_tags(tags)}"
        )

        # Postpone emitting tags until stream start.
        if self._audio._pending_tags is not None:
            self._audio._pending_tags.update(tags)
            return

        # TODO: Add proper tests for only emitting changed tags.
        unique = object()
        changed = []
        for key, value in tags.items():
            # Update any tags that changed, and store changed keys.
            if self._audio._tags.get(key, unique) != value:
                self._audio._tags[key] = value
                changed.append(key)

        if changed:
            logger.debug("Audio event: tags_changed(tags=%r)", changed)
            AudioListener.send("tags_changed", tags=changed)

    def on_missing_plugin(self, msg):
        desc = GstPbutils.missing_plugin_message_get_description(msg)
        debug = GstPbutils.missing_plugin_message_get_installer_detail(msg)
        gst_logger.debug("Got missing-plugin bus message: description=%r", desc)
        logger.warning("Could not find a %s to handle media.", desc)
        if GstPbutils.install_plugins_supported():
            logger.info(
                "You might be able to fix this by running: "
                'gst-installer "%s"',
                debug,
            )
        # TODO: store the missing plugins installer info in a file so we can
        # can provide a 'mopidy install-missing-plugins' if the system has the
        # required helper installed?

    def on_stream_start(self):
        gst_logger.debug("Got STREAM_START bus message")
        uri = self._audio._pending_uri
        logger.debug("Audio event: stream_changed(uri=%r)", uri)
        AudioListener.send("stream_changed", uri=uri)

        # Emit any postponed tags that we got after about-to-finish.
        tags, self._audio._pending_tags = self._audio._pending_tags, None
        self._audio._tags = tags or {}

        if tags:
            logger.debug("Audio event: tags_changed(tags=%r)", tags.keys())
            AudioListener.send("tags_changed", tags=tags.keys())

        if self._audio._pending_metadata:
            self._audio._playbin.send_event(self._audio._pending_metadata)
            self._audio._pending_metadata = None

    def on_segment(self, segment):
        gst_logger.debug(
            "Got SEGMENT pad event: "
            "rate=%(rate)s format=%(format)s start=%(start)s stop=%(stop)s "
            "position=%(position)s",
            {
                "rate": segment.rate,
                "format": Gst.Format.get_name(segment.format),
                "start": segment.start,
                "stop": segment.stop,
                "position": segment.position,
            },
        )
        position_ms = segment.position // Gst.MSECOND
        logger.debug("Audio event: position_changed(position=%r)", position_ms)
        AudioListener.send("position_changed", position=position_ms)


# TODO: create a player class which replaces the actors internals
[docs]class Audio(pykka.ThreadingActor): """ Audio output through `GStreamer <https://gstreamer.freedesktop.org/>`_. """ #: The GStreamer state mapped to :class:`mopidy.audio.PlaybackState` state = PlaybackState.STOPPED #: The software mixing interface :class:`mopidy.audio.actor.SoftwareMixer` mixer = None def __init__(self, config, mixer): super().__init__() self._config = config self._target_state = Gst.State.NULL self._buffering = False self._live_stream = False self._tags = {} self._pending_uri = None self._pending_tags = None self._pending_metadata = None self._playbin = None self._outputs = None self._queue = None self._about_to_finish_callback = None self._source_setup_callback = None self._handler = _Handler(self) self._appsrc = _Appsrc() self._signals = utils.Signals() if mixer and self._config["audio"]["mixer"] == "software": self.mixer = pykka.traversable(SoftwareMixer(mixer))
[docs] def on_start(self): self._thread = threading.current_thread() try: self._setup_preferences() self._setup_playbin() self._setup_outputs() self._setup_audio_sink() except GLib.GError as ex: logger.exception(ex) process.exit_process()
[docs] def on_stop(self): self._teardown_mixer() self._teardown_playbin()
def _setup_preferences(self): # TODO: move out of audio actor? # Fix for https://github.com/mopidy/mopidy/issues/604 registry = Gst.Registry.get() jacksink = registry.find_feature("jackaudiosink", Gst.ElementFactory) if jacksink: jacksink.set_rank(Gst.Rank.SECONDARY) def _setup_playbin(self): playbin = Gst.ElementFactory.make("playbin") playbin.set_property("flags", _GST_PLAY_FLAGS_AUDIO) # TODO: turn into config values... playbin.set_property("buffer-size", 5 << 20) # 5MB playbin.set_property("buffer-duration", 5 * Gst.SECOND) self._signals.connect(playbin, "source-setup", self._on_source_setup) self._signals.connect( playbin, "about-to-finish", self._on_about_to_finish ) self._playbin = playbin self._handler.setup_message_handling(playbin) def _teardown_playbin(self): self._handler.teardown_message_handling() self._handler.teardown_event_handling() self._signals.disconnect(self._playbin, "about-to-finish") self._signals.disconnect(self._playbin, "source-setup") self._playbin.set_state(Gst.State.NULL) def _setup_outputs(self): # We don't want to use outputs for regular testing, so just install # an unsynced fakesink when someone asks for a 'testoutput'. if self._config["audio"]["output"] == "testoutput": self._outputs = Gst.ElementFactory.make("fakesink") else: self._outputs = _Outputs() try: self._outputs.add_output(self._config["audio"]["output"]) except exceptions.AudioException: process.exit_process() # TODO: move this up the chain self._handler.setup_event_handling(self._outputs.get_static_pad("sink")) def _setup_audio_sink(self): audio_sink = Gst.ElementFactory.make("bin", "audio-sink") queue = Gst.ElementFactory.make("queue") volume = Gst.ElementFactory.make("volume") # Queue element to buy us time between the about-to-finish event and # the actual switch, i.e. about to switch can block for longer thanks # to this queue. # TODO: See if settings should be set to minimize latency. Previous # setting breaks appsrc, and settings before that broke on a few # systems. So leave the default to play it safe. buffer_time = self._config["audio"]["buffer_time"] if buffer_time is not None and buffer_time > 0: queue.set_property("max-size-time", buffer_time * Gst.MSECOND) audio_sink.add(queue) audio_sink.add(self._outputs) audio_sink.add(volume) queue.link(volume) volume.link(self._outputs) if self.mixer: self.mixer.setup(volume, self.actor_ref.proxy().mixer) ghost_pad = Gst.GhostPad.new("sink", queue.get_static_pad("sink")) audio_sink.add_pad(ghost_pad) self._playbin.set_property("audio-sink", audio_sink) self._queue = queue def _teardown_mixer(self): if self.mixer: self.mixer.teardown() def _on_about_to_finish(self, element): if self._thread == threading.current_thread(): logger.error( "about-to-finish in actor, aborting to avoid deadlock." ) return gst_logger.debug("Got about-to-finish event.") if self._about_to_finish_callback: logger.debug("Running about-to-finish callback.") self._about_to_finish_callback() def _on_source_setup(self, element, source): gst_logger.debug( "Got source-setup signal: element=%s", source.__class__.__name__ ) if source.get_factory().get_name() == "appsrc": self._appsrc.configure(source) else: self._appsrc.reset() if self._source_setup_callback: logger.debug("Running source-setup callback") self._source_setup_callback(source) if self._live_stream and hasattr(source.props, "is_live"): gst_logger.debug("Enabling live stream mode") source.set_live(True) utils.setup_proxy(source, self._config["proxy"])
[docs] def set_uri(self, uri, live_stream=False, download=False): """ Set URI of audio to be played. You *MUST* call :meth:`prepare_change` before calling this method. :param uri: the URI to play :type uri: string :param live_stream: disables buffering, reducing latency for stream, and discarding data when paused :type live_stream: bool :param download: enables "download" buffering mode :type download: bool """ # XXX: Hack to workaround issue on Mac OS X where volume level # does not persist between track changes. mopidy/mopidy#886 if self.mixer is not None: current_volume = self.mixer.get_volume() else: current_volume = None flags = _GST_PLAY_FLAGS_AUDIO if download: flags |= _GST_PLAY_FLAGS_DOWNLOAD logger.debug(f"Flags: {flags}") if live_stream and download: logger.warning( "Ambiguous buffering flags: " "'live_stream' and 'download' should not both be set." ) self._pending_uri = uri self._pending_tags = {} self._live_stream = live_stream self._playbin.set_property("flags", flags) self._playbin.set_property("uri", uri) if self.mixer is not None and current_volume is not None: self.mixer.set_volume(current_volume)
[docs] def set_appsrc( self, caps, need_data=None, enough_data=None, seek_data=None ): """ Switch to using appsrc for getting audio to be played. You *MUST* call :meth:`prepare_change` before calling this method. :param caps: GStreamer caps string describing the audio format to expect :type caps: string :param need_data: callback for when appsrc needs data :type need_data: callable which takes data length hint in ms :param enough_data: callback for when appsrc has enough data :type enough_data: callable :param seek_data: callback for when data from a new position is needed to continue playback :type seek_data: callable which takes time position in ms """ self._appsrc.prepare( Gst.Caps.from_string(caps), need_data, enough_data, seek_data ) uri = "appsrc://" self._pending_uri = uri self._live_stream = False self._playbin.set_property("flags", _GST_PLAY_FLAGS_AUDIO) self._playbin.set_property("uri", uri)
[docs] def emit_data(self, buffer_): """ Call this to deliver raw audio data to be played. If the buffer is :class:`None`, the end-of-stream token is put on the playbin. We will get a GStreamer message when the stream playback reaches the token, and can then do any end-of-stream related tasks. Note that the URI must be set to ``appsrc://`` for this to work. Returns :class:`True` if data was delivered. :param buffer_: buffer to pass to appsrc :type buffer_: :class:`Gst.Buffer` or :class:`None` :rtype: boolean """ return self._appsrc.push(buffer_)
[docs] def set_source_setup_callback(self, callback): """ Configure audio to use a source-setup callback. This should be used to modify source-specific properties such as login details. :param callable callback: Callback to run when we setup the source. """ self._source_setup_callback = callback
[docs] def set_about_to_finish_callback(self, callback): """ Configure audio to use an about-to-finish callback. This should be used to achieve gapless playback. For this to work the callback *MUST* call :meth:`set_uri` with the new URI to play and block until this call has been made. :meth:`prepare_change` is not needed before :meth:`set_uri` in this one special case. :param callable callback: Callback to run when we need the next URI. """ self._about_to_finish_callback = callback
[docs] def get_position(self): """ Get position in milliseconds. :rtype: int """ success, position = self._playbin.query_position(Gst.Format.TIME) if not success: # TODO: take state into account for this and possibly also return # None as the unknown value instead of zero? logger.debug("Position query failed") return 0 return utils.clocktime_to_millisecond(position)
[docs] def set_position(self, position): """ Set position in milliseconds. :param position: the position in milliseconds :type position: int :rtype: :class:`True` if successful, else :class:`False` """ # TODO: double check seek flags in use. gst_position = utils.millisecond_to_clocktime(position) gst_logger.debug("Sending flushing seek: position=%r", gst_position) # Send seek event to the queue not the playbin. The default behavior # for bins is to forward this event to all sinks. Which results in # duplicate seek events making it to appsrc. Since elements are not # allowed to act on the seek event, only modify it, this should be safe # to do. result = self._queue.seek_simple( Gst.Format.TIME, Gst.SeekFlags.FLUSH, gst_position ) return result
[docs] def start_playback(self): """ Notify GStreamer that it should start playback. :rtype: :class:`True` if successfull, else :class:`False` """ return self._set_state(Gst.State.PLAYING)
[docs] def pause_playback(self): """ Notify GStreamer that it should pause playback. :rtype: :class:`True` if successfull, else :class:`False` """ return self._set_state(Gst.State.PAUSED)
[docs] def prepare_change(self): """ Notify GStreamer that we are about to change state of playback. This function *MUST* be called before changing URIs or doing changes like updating data that is being pushed. The reason for this is that GStreamer will reset all its state when it changes to :attr:`Gst.State.READY`. """ return self._set_state(Gst.State.READY)
[docs] def stop_playback(self): """ Notify GStreamer that is should stop playback. :rtype: :class:`True` if successfull, else :class:`False` """ return self._set_state(Gst.State.NULL)
[docs] def wait_for_state_change(self): """Block until any pending state changes are complete. Should only be used by tests. """ self._playbin.get_state(timeout=Gst.CLOCK_TIME_NONE)
[docs] def enable_sync_handler(self): """Enable manual processing of messages from bus. Should only be used by tests. """ def sync_handler(bus, message): self._handler.on_message(bus, message) return Gst.BusSyncReply.DROP bus = self._playbin.get_bus() bus.set_sync_handler(sync_handler)
def _set_state(self, state): """ Internal method for setting the raw GStreamer state. .. digraph:: gst_state_transitions graph [rankdir="LR"]; node [fontsize=10]; "NULL" -> "READY" "PAUSED" -> "PLAYING" "PAUSED" -> "READY" "PLAYING" -> "PAUSED" "READY" -> "NULL" "READY" -> "PAUSED" :param state: State to set playbin to. One of: `Gst.State.NULL`, `Gst.State.READY`, `Gst.State.PAUSED` and `Gst.State.PLAYING`. :type state: :class:`Gst.State` :rtype: :class:`True` if successfull, else :class:`False` """ if state < Gst.State.PAUSED: self._buffering = False self._target_state = state result = self._playbin.set_state(state) gst_logger.debug( "Changing state to %s: result=%s", state.value_name, result.value_name, ) if result == Gst.StateChangeReturn.FAILURE: logger.warning( "Setting GStreamer state to %s failed", state.value_name ) return False # TODO: at this point we could already emit stopped event instead # of faking it in the message handling when result=OK return True # TODO: bake this into setup appsrc perhaps?
[docs] def set_metadata(self, track): """ Set track metadata for currently playing song. Only needs to be called by sources such as ``appsrc`` which do not already inject tags in playbin, e.g. when using :meth:`emit_data` to deliver raw audio data to GStreamer. :param track: the current track :type track: :class:`mopidy.models.Track` """ taglist = Gst.TagList.new_empty() artists = [a for a in (track.artists or []) if a.name] def set_value(tag, value): gobject_value = GObject.Value() gobject_value.init(GObject.TYPE_STRING) gobject_value.set_string(value) taglist.add_value(Gst.TagMergeMode.REPLACE, tag, gobject_value) # Default to blank data to trick shoutcast into clearing any previous # values it might have. # TODO: Verify if this works at all, likely it doesn't. set_value(Gst.TAG_ARTIST, " ") set_value(Gst.TAG_TITLE, " ") set_value(Gst.TAG_ALBUM, " ") if artists: set_value(Gst.TAG_ARTIST, ", ".join(a.name for a in artists)) if track.name: set_value(Gst.TAG_TITLE, track.name) if track.album and track.album.name: set_value(Gst.TAG_ALBUM, track.album.name) gst_logger.debug( "Sending TAG event for track %r: %r", track.uri, taglist.to_string() ) event = Gst.Event.new_tag(taglist) if self._pending_uri: self._pending_metadata = event else: self._playbin.send_event(event)
[docs] def get_current_tags(self): """ Get the currently playing media's tags. If no tags have been found, or nothing is playing this returns an empty dictionary. For each set of tags we collect a tags_changed event is emitted with the keys of the changes tags. After such calls users may call this function to get the updated values. :rtype: {key: [values]} dict for the current media. """ # TODO: should this be a (deep) copy? most likely yes # TODO: should we return None when stopped? # TODO: support only fetching keys we care about? return self._tags