Add example rec_unlimited.py

Author: mgeier

doc/examples.rst

@@ -30,3 +30,10 @@ Real-Time Text-Mode Spectrogram
 :download:`spectrogram.py <../examples/spectrogram.py>`
 
 .. literalinclude:: ../examples/spectrogram.py
+
+Recording with Arbitrary Duration
+---------------------------------
+
+:download:`rec_unlimited.py <../examples/rec_unlimited.py>`
+
+.. literalinclude:: ../examples/rec_unlimited.py

examples/rec_unlimited.py

@@ -0,0 +1,75 @@
+#!/usr/bin/env python3
+"""Create a recording with arbitrary duration.
+
+PySoundFile (https://github.com/bastibe/PySoundFile/) has to be installed!
+
+WARNING: This works only in Python 3.x!
+
+"""
+import argparse
+import tempfile
+from queue import Queue
+
+
+def int_or_str(text):
+    """Helper function for argument parsing."""
+    try:
+        return int(text)
+    except ValueError:
+        return text
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument(
+    '-l', '--list-devices', action='store_true',
+    help='show list of audio devices and exit')
+parser.add_argument(
+    '-d', '--device', type=int_or_str,
+    help='input device (numeric ID or substring)')
+parser.add_argument(
+    '-r', '--samplerate', type=int, help='sampling rate')
+parser.add_argument(
+    '-c', '--channels', type=int, default=1, help='number of input channels')
+parser.add_argument(
+    'filename', nargs='?', metavar='FILENAME',
+    help='audio file to store recording to')
+parser.add_argument(
+    '-t', '--subtype', type=str, help='sound file subtype (e.g. "PCM_24")')
+args = parser.parse_args()
+
+try:
+    import sounddevice as sd
+    import soundfile as sf
+
+    if args.list_devices:
+        print(sd.query_devices())
+        parser.exit()
+    if args.samplerate is None:
+        device_info = sd.query_devices(args.device, 'input')
+        # soundfile expects an int, sounddevice provides a float:
+        args.samplerate = int(device_info['default_samplerate'])
+    if args.filename is None:
+        args.filename = tempfile.mktemp(prefix='rec_unlimited_',
+                                        suffix='.wav', dir='')
+    queue = Queue()
+
+    def callback(indata, frames, time, status):
+        """This is called (from a separate thread) for each audio block."""
+        if status:
+            print(status, flush=True)
+        queue.put(indata.copy())
+
+    # Make sure the file is opened before recording anything:
+    with sf.SoundFile(args.filename, mode='x', samplerate=args.samplerate,
+                      channels=args.channels, subtype=args.subtype) as file:
+        with sd.InputStream(samplerate=args.samplerate, device=args.device,
+                            channels=args.channels, callback=callback):
+            print("#" * 80)
+            print("press Ctrl+C to stop the recording")
+            print("#" * 80)
+            while True:
+                file.write(queue.get())
+
+except KeyboardInterrupt:
+    parser.exit('\nRecording finished: ' + repr(args.filename))
+except Exception as e:
+    parser.exit(type(e).__name__ + ': ' + str(e))