PythonGStreamer: Difference between revisions

Latest revision as of 11:41, 1 June 2009

Generating random tones

A python random oscillator stream:

import pygst
pygst.require("0.10")
import gst

pipeline = gst.Pipeline("mypipeline")
audiotestsrc = gst.element_factory_make("audiotestsrc", "audio")
pipeline.add(audiotestsrc)
sink = gst.element_factory_make("alsasink", "sink")
pipeline.add(sink)
audiotestsrc.link(sink)
audiotestsrc.set_property("freq", 800)
pipeline.set_state(gst.STATE_PLAYING)

import time, random

while 1:
	f = random.randint(200, 800)
	print "setting freq to: %d" % f 
	audiotestsrc.set_property("freq", f)
	time.sleep(1.0/random.randint(1, 10))

Other Examples

@@ Line 1: / Line 1: @@
 Using [[Python]] to program [[GStreamer]]
-== Generating random tones ===
+== Generating random tones ==
 A python random oscillator stream:
@@ Line 27: / Line 27: @@
 </source>
-== A command-line spectrum analyzer ==
+== Other Examples ==
-[[Media:Spectrum.zip]]
-<source lang="python">
-import pygst
-pygst.require("0.10")
-import gst, gobject
-import time, thread
-class Spectrum:
-	def __init__(self):
-		# Create a gstreamer pipeline, listen to it's messages via on_message callback
-		# listener_desc = 'alsasrc ! spectrum ! fakesink'
-		listener_desc = 'alsasrc ! spectrum bands=64 ! fakesink'
-		self.listener = gst.parse_launch(listener_desc)
-		bus = self.listener.get_bus()
-		bus.add_signal_watch()
-		bus.connect("message", self.on_message)
-	def on_message (self, bus, message):
-		""" callback function for gstreamer messages """
-		s = message.structure
-		# print "message.name", s.get_name()
-		# print "message.structure.keys", s.keys()
-		if s and s.get_name() == "spectrum":
-			# spectrum messages have 'endtime', 'timestamp', 'stream-time', 'running-time', 'duration', 'magnitude'
-			# print len(s['magnitude'])
-			print "data: " + " ".join([str(x) for x in s['magnitude']])
-		return True
-	def start(self):
-		self.listener.set_state(gst.STATE_PLAYING)
-		while True:
-			time.sleep(1)
+* [[Level.py | Level analyzer]]
-# Run the Spectrum object in it's own thread, then start the gobject.MainLoop as required
+* [[Spectrum.py | Spectral analysis]]
-spectrum = Spectrum()
-thread.start_new_thread(spectrum.start, ())
-gobject.threads_init()
-loop = gobject.MainLoop()
-loop.run()
-</source>
-== Other Examples ==
 * [[ListeningAndWatching]]