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