Add an example to record audio

diff --git a/examples/record_sound.py b/examples/record_sound.py
new file mode 100755 (executable)
index 0000000..c3277d4
--- /dev/null
+++ b/examples/record_sound.py
@@ -0,0 +1,89 @@
+#!/usr/bin/env python3
+
+'''
+Simple example to demonstrate using Gst.DeviceMonitor and `transcodebin` to
+record audio from a microphone into an .oga file
+'''
+import gi
+import sys
+gi.require_version('Gst', '1.0')
+gi.require_version('GstPbutils', '1.0')
+gi.require_version('GLib', '2.0')
+gi.require_version('GObject', '2.0')
+from gi.repository import GLib, GObject, Gst, GstPbutils
+
+def bus_call(bus, message, loop):
+    t = message.type
+    Gst.debug_bin_to_dot_file_with_ts(pipeline, Gst.DebugGraphDetails.ALL, "test")
+    if t == Gst.MessageType.EOS:
+        sys.stdout.write("End-of-stream\n")
+        loop.quit()
+    elif t == Gst.MessageType.ERROR:
+        err, debug = message.parse_error()
+        sys.stderr.write("Error: %s: %s\n" % (err, debug))
+        loop.quit()
+    return True
+
+def stop(loop, pipeline):
+    _, position = pipeline.query_position(Gst.Format.TIME)
+    print("Position: %s\r" % Gst.TIME_ARGS(position))
+
+    if position > 10 * Gst.SECOND:
+        loop.quit()
+        print("Stopping after 10 seconds")
+        return False
+
+    return True
+
+if __name__ == "__main__":
+    Gst.init(sys.argv)
+
+    if len(sys.argv) != 2:
+        print("Missing <output-location> parametter")
+        sys.exit(1)
+
+    monitor = Gst.DeviceMonitor.new()
+    monitor.add_filter("Audio/Source", None)
+    monitor.start()
+
+    # This is happening synchonously, use the GstBus based API and
+    # monitor.start() to avoid blocking the main thread.
+    devices = monitor.get_devices()
+
+    if not devices:
+        print("No microphone found...")
+        sys.exit(1)
+
+    default = [d for d in devices if d.get_properties().get_value("is-default") is True]
+    if len(default) == 1:
+        device = default[0]
+    else:
+        print("Avalaible microphones:")
+        for i, d in enumerate(devices):
+            print("%d - %s" % (i, d.get_display_name()))
+        res = int(input("Select device: "))
+        device = devices[res]
+
+    pipeline = Gst.ElementFactory.make("pipeline", None)
+    source = device.create_element()
+    transcodebin = Gst.ElementFactory.make("transcodebin", None)
+    Gst.util_set_object_arg(transcodebin, "profile", "video/ogg:audio/x-opus")
+    filesink = Gst.ElementFactory.make("filesink", None)
+    filesink.props.location = sys.argv[1]
+
+    pipeline.add(source, transcodebin, filesink)
+    source.link(transcodebin)
+    transcodebin.link(filesink)
+
+    pipeline.set_state(Gst.State.PLAYING)
+
+    bus = pipeline.get_bus()
+    bus.add_signal_watch()
+
+    loop = GLib.MainLoop()
+    GLib.timeout_add_seconds(1, stop, loop, pipeline)
+    bus.connect ("message", bus_call, loop)
+    loop.run()
+
+    pipeline.set_state(Gst.State.NULL)
+    pipeline.get_state(Gst.CLOCK_TIME_NONE)
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