mopidy/mopidy/outputs/gstreamer.py

181 lines
6.5 KiB
Python

import gobject
import pygst
pygst.require('0.10')
import gst
import logging
from mopidy.process import BaseProcess, unpickle_connection
logger = logging.getLogger('mopidy.outputs.gstreamer')
class GStreamerOutput(object):
"""
Audio output through GStreamer.
Starts the :class:`GStreamerProcess`.
"""
def __init__(self, core_queue, input_connection):
process = GStreamerProcess(core_queue, input_connection)
process.start()
class GStreamerProcess(BaseProcess):
"""
A process for all work related to GStreamer.
The main loop processes events from both Mopidy and GStreamer.
"""
def __init__(self, core_queue, input_connection):
super(GStreamerProcess, self).__init__()
self.core_queue = core_queue
self.input_connection = input_connection
self.gobject_context = None
self.gst_pipeline = None
self.gst_bus = None
self.gst_bus_id = None
self.gst_uri_src = None
self.gst_data_src = None
self.gst_volume = None
self.gst_sink = None
def run_inside_try(self):
self.setup()
while True:
# FIXME Should we block on poll() or not? Need to see iteration()
# behaviour first.
if self.input_connection.poll():
message = self.input_connection.recv()
self.process_mopidy_message(message)
self.gobject_context.iteration(True)
def setup(self):
# See http://www.jejik.com/articles/2007/01/
# python-gstreamer_threading_and_the_main_loop/ for details.
gobject.threads_init()
self.gobject_context = gobject.MainLoop().get_context()
# A pipeline consisting of many elements
self.gst_pipeline = gst.Pipeline("pipeline")
# Setup bus and message processor
self.gst_bus = self.gst_pipeline.get_bus()
self.gst_bus.add_signal_watch()
self.gst_bus_id = self.gst_bus.connect('message',
self.process_gst_message)
# Bin for playing audio URIs
self.gst_uri_src = gst.element_factory_make('uridecodebin', 'uri_src')
self.gst_pipeline.add(self.gst_uri_src)
# Bin for playing audio data
self.gst_data_src = gst.element_factory_make('appsrc', 'data_src')
self.gst_pipeline.add(self.gst_data_src)
# Volume filter
self.gst_volume = gst.element_factory_make('volume', 'volume')
self.gst_pipeline.add(self.gst_volume)
# Audio output sink
self.gst_sink = gst.element_factory_make('autoaudiosink', 'sink')
self.gst_pipeline.add(self.gst_sink)
# Add callback that will link uri_src output with volume filter input
# when the output pad is ready.
# See http://stackoverflow.com/questions/2993777 for details.
def on_new_decoded_pad(dbin, pad, is_last):
uri_src = pad.get_parent()
pipeline = uri_src.get_parent()
volume = pipeline.get_by_name('volume')
uri_src.link(volume)
logger.debug("Linked uri_src's new decoded pad to volume filter")
# FIXME uridecodebin got no new-decoded-pad signal, but it's
# subcomponent decodebin2 got that signal. Fixing this is postponed
# till after data_src is up and running perfectly
#self.gst_uri_src.connect('new-decoded-pad', on_new_decoded_pad)
# Link data source output with volume filter input
self.gst_data_src.link(self.gst_volume)
# Link volume filter output to audio sink input
self.gst_volume.link(self.gst_sink)
def process_mopidy_message(self, message):
"""Process messages from the rest of Mopidy."""
if message['command'] == 'play_uri':
response = self.play_uri(message['uri'])
connection = unpickle_connection(message['reply_to'])
connection.send(response)
elif message['command'] == 'deliver_data':
# FIXME Do we care about sending responses for every data delivery?
self.deliver_data(message['caps'], message['data'])
elif message['command'] == 'set_state':
response = self.set_state(message['state'])
connection = unpickle_connection(message['reply_to'])
connection.send(response)
else:
logger.warning(u'Cannot handle message: %s', message)
def process_gst_message(self, bus, message):
"""Process messages from GStreamer."""
if message.type == gst.MESSAGE_EOS:
self.core_queue.put({'message': 'end_of_track'})
elif message.type == gst.MESSAGE_ERROR:
self.set_state('NULL')
error, debug = message.parse_error()
logger.error(u'%s %s', error, debug)
# FIXME Should we send 'stop_playback' to core here? Can we
# differentiate on how serious the error is?
def deliver_data(self, caps_string, data):
"""Deliver audio data to be played"""
caps = gst.caps_from_string(caps_string)
buffer_ = gst.Buffer(data)
buffer_.set_caps(caps)
self.gst_data_src.emit('push-buffer', buffer_)
def play_uri(self, uri):
"""Play audio at URI"""
self.set_state('READY')
self.gst_uri_src.set_property('uri', uri)
self.set_state('PLAYING')
# TODO Return status
def set_state(self, state_name):
"""
Set the GStreamer state. Returns :class:`True` if successful.
.. digraph:: gst_state_transitions
"NULL" -> "READY"
"PAUSED" -> "PLAYING"
"PAUSED" -> "READY"
"PLAYING" -> "PAUSED"
"READY" -> "NULL"
"READY" -> "PAUSED"
:param state_name: NULL, READY, PAUSED, or PLAYING
:type state_name: string
:rtype: :class:`True` or :class:`False`
"""
result = self.gst_pipeline.set_state(
getattr(gst, 'STATE_' + state_name))
if result == gst.STATE_CHANGE_SUCCESS:
logger.debug('Setting GStreamer state to %s: OK', state_name)
return True
else:
logger.warning('Setting GStreamer state to %s: failed', state_name)
return False
def get_volume(self):
"""Get volume in range [0..100]"""
gst_volume = self.gst_volume.get_property('volume')
return int(gst_volume * 100)
def set_volume(self, volume):
"""Set volume in range [0..100]"""
gst_volume = volume / 100.0
self.gst_volume.set_property('volume', gst_volume)