Started with sounddevice renderer implementation

Author: dschreij

mediadecoder/decoder.py

@@ -170,7 +170,7 @@ def load_media(self, mediafile, play_audio=True):
 				logger.debug("Video clip FPS: {}".format(self.fps))
 
 				if play_audio and self.clip.audio:
-					buffersize = int(self.frame_interval*self.clip.audio.fps)+1
+					buffersize = int(self.frame_interval*self.clip.audio.fps)
 					self.audioformat = {
 						'nbytes':  	  	2,
 						'nchannels':	self.clip.audio.nchannels,

mediadecoder/soundrenderers/__init__.py

@@ -1,5 +1,6 @@
 from mediadecoder.soundrenderers.pyaudiorenderer import SoundrendererPyAudio
 from mediadecoder.soundrenderers.pygamerenderer import SoundrendererPygame
+from mediadecoder.soundrenderers.sounddevicerenderer import SoundrendererSounddevice
 
-__all__ = ['SoundrendererPygame', 'SoundrendererPyAudio']
+__all__ = ['SoundrendererPygame', 'SoundrendererPyAudio','SoundrendererSounddevice']
 

mediadecoder/soundrenderers/sounddevicerenderer.py

@@ -0,0 +1,58 @@
+import time
+import sounddevice as sd
+
+try:
+	# Python 3
+	from queue import Queue, Empty
+except:
+	# Python 2
+	from Queue import Queue, Empty
+
+from mediadecoder.soundrenderers._base import SoundRenderer
+
+queue_timeout=0.01
+
+class SoundrendererSounddevice(SoundRenderer):
+	""" Uses pyaudio to play sound """
+	def __init__(self, audioformat, queue=None):
+		"""Constructor.
+		Creates a pyaudio sound renderer.
+		
+		Parameters
+		----------
+		audioformat : dict
+			A dictionary containing the properties of the audiostream
+		queue : Queue.queue
+			A queue object which serves as a buffer on which the individual
+			audio frames are placed by the decoder.
+		"""
+		if not queue is None:
+			self.queue = queue
+
+		self.stream = sd.OutputStream(
+			channels  	= audioformat["nchannels"],
+			samplerate 	= audioformat["fps"],
+			blocksize 	= 0,
+			callback 	= self.get_frame
+		)
+		self.keep_listening = True
+
+	def get_frame(self, outdata, frames, timedata, status):
+		""" Callback function for the pyaudio stream. Don't use directly. """
+		try:
+			chunk = self.queue.get_nowait()
+			outdata[:] = chunk
+		except Empty:
+			outdata.fill(0)
+
+	def start(self):
+		""" Initializes the stream. """
+		if not hasattr(self, 'queue'):
+			raise RuntimeError("Audio queue is not intialized.")
+		self.stream.start()
+
+	def close_stream(self):
+		""" Closes the stream. Performs cleanup. """
+		self.keep_listening = False
+		self.stream.stop
+		self.stream.close()

play.py

@@ -133,8 +133,10 @@ def load_media(self, vidSource):
 		if(self.decoder.audioformat):
 			if self.soundrenderer == "pygame":
 				self.audio = SoundrendererPygame(self.decoder.audioformat)
-			if self.soundrenderer == "pyaudio":
+			elif self.soundrenderer == "pyaudio":
 				self.audio = SoundrendererPyAudio(self.decoder.audioformat)
+			elif self.soundrenderer == "sounddevice":
+				self.audio = SoundrendererSounddevice(self.decoder.audioformat)
 			self.decoder.set_audiorenderer(self.audio)
 
 	def __textureSetup(self):
@@ -289,8 +291,8 @@ def pause(self):
 	parser.add_argument("-l", "--loop", help="loop the video", 
 		action="store_true", default=False)
 	parser.add_argument("-s", "--soundrenderer", help="the backend that should "
-		" render the sound (default: pyaudio)", choices=["pygame","pyaudio"], 
-		default="pyaudio")
+		" render the sound (default: pyaudio)", choices=["pygame","pyaudio",
+		"sounddevice"], default="pyaudio")
 	parser.add_argument("-r", "--resolution", help="The resolution of the video."
 		"\nSpecify as <width>x<height> (default: 1024x768)", default="1024x768")