Implemented recorder

birbnetes_iot_platform_raspberry/__init__.py

@@ -1 +1,3 @@
 from .led_stuff import BirbnetesIoTPlatformStatusDriver
+from .playback_stuff import BirbnetesIoTPlatformPlaybackDriver
+from .record_stuff import BirbnetesIoTPlatformRecordDriver

birbnetes_iot_platform_raspberry/record_stuff.py

@@ -0,0 +1,88 @@
+from typing import Optional, Tuple
+import alsaaudio
+import tempfile
+from queue import Queue, Empty
+from threading import Thread
+import wave
+
+SAMPLE_RATE = 44100
+MICROPHONE = 'default'
+DEST_FOLDER = "/dev/shm/"
+
+
+class SlicedRecorder(Thread):
+
+    BYTES_PER_SAMPLE = 2 # 16bit
+
+    def __init__(self, slice_size: float, sample_rate=SAMPLE_RATE, microphone=MICROPHONE, dest_folder=DEST_FOLDER):
+        super().__init__()
+        self._output_queue = Queue()
+        self._samples_per_slice = slice_size * sample_rate
+        self._dest_folder = dest_folder
+        self._sample_rate = sample_rate
+        self._inp = alsaaudio.PCM(
+            alsaaudio.PCM_CAPTURE,
+            alsaaudio.PCM_NORMAL,
+            microphone,
+            channels=1,
+            rate=sample_rate,
+            format=alsaaudio.PCM_FORMAT_S16_LE, # = 2bytes
+            periodsize=512
+        )
+        self._active = True
+
+    def _request_new_file(self) -> Tuple[str, wave.Wave_write]:
+        _, record_path = tempfile.mkstemp(prefix="rec", suffix=".wav", dir=self._dest_folder)
+        wavefile = wave.open(record_path, 'wb')
+        wavefile.setnchannels(1)  # mono
+        wavefile.setframerate(self._sample_rate)
+        wavefile.setsampwidth(self.BYTES_PER_SAMPLE)  # 16bit
+        return record_path, wavefile
+
+    def run(self):
+
+        current_working_file_name, current_working_file = self._request_new_file()
+        current_samples_saved = 0
+
+        while self._active:
+            length, data = self._inp.read()
+
+            if length > 0:  # will be always larger than zero (except on error)
+                file_size_after_append = current_samples_saved + length
+
+                if file_size_after_append > self._samples_per_slice:  # Appending this would cause a too big slice
+
+                    samples_append_to_this_slice = self._samples_per_slice - current_samples_saved
+
+                    current_working_file.writeframes(data[:(samples_append_to_this_slice*self.BYTES_PER_SAMPLE)])
+
+                    current_working_file.close()
+                    self._output_queue.put(current_working_file_name)
+                    current_working_file_name, current_working_file = self._request_new_file()
+
+                    current_working_file.writeframes(data[(samples_append_to_this_slice*self.BYTES_PER_SAMPLE):])
+                    current_samples_saved = length - samples_append_to_this_slice
+
+                else:  # it is safe to append, the resulting file will be smaller than the slice
+                    current_working_file.writeframes(data)
+                    current_samples_saved = file_size_after_append
+
+    def get_recording(self, blocking: bool) -> Optional[str]:
+        try:
+            return self._output_queue.get(block=blocking)
+        except Empty:
+            return None
+
+    def stop(self):
+        self._active = False
+
+
+class BirbnetesIoTPlatformRecordDriver:
+
+    @classmethod
+    def init(cls, sample_length_sec: float):
+        pass
+
+    @classmethod
+    def get_recording(cls, blocking: bool = False):
+        pass