1 files changed, 72 insertions, 0 deletions
diff --git a/src/mic_clipper/audio_input.py b/src/mic_clipper/audio_input.py
new file mode 100644
index 0000000..1d77aa0
--- /dev/null
+++ b/src/mic_clipper/audio_input.py
@@ -0,0 +1,72 @@
+"""PipeWire/Pulse microphone capture through the local ffmpeg binary."""
+
+from __future__ import annotations
+
+import subprocess
+from collections.abc import Iterator
+
+import numpy as np
+
+from mic_clipper.vad import FRAME_SAMPLES
+
+
+class AudioInputUnavailable(RuntimeError):
+    """The dynamic Pulse default source could not supply another frame."""
+
+
+class PulseAudioInput:
+    """Yield fixed 16 kHz mono float PCM frames from Pulse's `default` source."""
+
+    @staticmethod
+    def command() -> list[str]:
+        return [
+            "ffmpeg",
+            "-nostdin",
+            "-hide_banner",
+            "-loglevel",
+            "error",
+            "-f",
+            "pulse",
+            "-sample_rate",
+            "16000",
+            "-channels",
+            "1",
+            "-i",
+            "default",
+            "-ac",
+            "1",
+            "-ar",
+            "16000",
+            "-f",
+            "f32le",
+            "pipe:1",
+        ]
+
+    def frames(self) -> Iterator[np.ndarray]:
+        process = subprocess.Popen(
+            self.command(),
+            stdin=subprocess.DEVNULL,
+            stdout=subprocess.PIPE,
+            stderr=subprocess.PIPE,
+        )
+        assert process.stdout is not None
+        assert process.stderr is not None
+        try:
+            while True:
+                payload = process.stdout.read(FRAME_SAMPLES * np.dtype("<f4").itemsize)
+                if len(payload) != FRAME_SAMPLES * np.dtype("<f4").itemsize:
+                    error = process.stderr.read(4096).decode("utf-8", errors="replace").strip()
+                    return_code = process.wait()
+                    detail = f": {error}" if error else ""
+                    raise AudioInputUnavailable(
+                        f"ffmpeg Pulse input ended with exit code {return_code}{detail}"
+                    )
+                yield np.frombuffer(payload, dtype="<f4").copy()
+        finally:
+            if process.poll() is None:
+                process.terminate()
+                try:
+                    process.wait(timeout=5)
+                except subprocess.TimeoutExpired:
+                    process.kill()
+                    process.wait()