feat: add voice pitch shifting

F6/F7 adjust outgoing voice pitch in 1-semitone steps (-12 to +12).
PitchShifter integrates into the capture path at dequeue time so the
PortAudio callback is never blocked.  Status bar shows current pitch
when non-zero.  Config reload treats pitch as a safe change.

pyproject.toml

@@ -11,6 +11,7 @@ dependencies = [
     "textual>=1.0.0",
     "pymumble>=1.6",
     "sounddevice>=0.5.0",
+    "numpy>=1.24.0",
     "tomli>=2.0.0;python_version<'3.11'",
 ]
 

src/tuimble/app.py

@@ -118,6 +118,7 @@ class StatusBar(Static):
     server_info = reactive("")
     output_vol = reactive(100)
     input_vol = reactive(100)
+    pitch = reactive(0)
 
     @staticmethod
     def _vol_bar(pct: int) -> str:
@@ -157,9 +158,14 @@ class StatusBar(Static):
             f"  [dim]out[/]{self._vol_bar(self.output_vol)}"
             f" [dim]in[/]{self._vol_bar(self.input_vol)}"
         )
+        if self.pitch != 0:
+            sign = "+" if self.pitch > 0 else ""
+            pitch_str = f"  [dim]pitch[/]{sign}{self.pitch}"
+        else:
+            pitch_str = ""
         info = f"  [dim]{self.server_info}[/]" if self.server_info else ""
         deaf = f"{deaf_full}  " if deaf_full else ""
-        return f" {conn_full}  {deaf}{ptt_full}{vol}{info}"
+        return f" {conn_full}  {deaf}{ptt_full}{vol}{pitch_str}{info}"
 
 
 class ChannelTree(Static):
@@ -412,6 +418,8 @@ class TuimbleApp(App):
         ("f2", "cycle_output_volume", "Vol Out"),
         ("f3", "cycle_input_volume", "Vol In"),
         ("f5", "reload_config", "Reload"),
+        ("f6", "pitch_down", "Pitch-"),
+        ("f7", "pitch_up", "Pitch+"),
         ("q", "quit", "Quit"),
         ("ctrl+c", "quit", "Quit"),
     ]
@@ -431,6 +439,7 @@ class TuimbleApp(App):
         )
         self._audio.input_gain = acfg.input_gain
         self._audio.output_gain = acfg.output_gain
+        self._audio.pitch = acfg.pitch
         self._device_monitor = DeviceMonitor(self._on_device_change)
         self._pending_reload: Config | None = None
         self._tree_refresh_timer = None
@@ -469,6 +478,7 @@ class TuimbleApp(App):
         status = self.query_one("#status", StatusBar)
         status.output_vol = int(self._audio.output_gain * 100)
         status.input_vol = int(self._audio.input_gain * 100)
+        status.pitch = int(self._audio.pitch)
 
         chatlog = self.query_one("#chatlog", ChatLog)
         chatlog.write("[dim]tuimble v0.1.0[/dim]")
@@ -687,6 +697,7 @@ class TuimbleApp(App):
         )
         self._audio.input_gain = acfg.input_gain
         self._audio.output_gain = acfg.output_gain
+        self._audio.pitch = acfg.pitch
 
         if self._client.connected:
             self._start_audio()
@@ -763,6 +774,26 @@ class TuimbleApp(App):
         chatlog = self.query_one("#chatlog", ChatLog)
         chatlog.write(f"[dim]input volume {pct}%[/dim]")
 
+    # -- pitch ----------------------------------------------------------------
+
+    def action_pitch_down(self) -> None:
+        """Decrease voice pitch by 1 semitone."""
+        self._audio.pitch = max(-12.0, self._audio.pitch - 1.0)
+        st = int(self._audio.pitch)
+        status = self.query_one("#status", StatusBar)
+        status.pitch = st
+        chatlog = self.query_one("#chatlog", ChatLog)
+        chatlog.write(f"[dim]pitch {st:+d} semitones[/dim]")
+
+    def action_pitch_up(self) -> None:
+        """Increase voice pitch by 1 semitone."""
+        self._audio.pitch = min(12.0, self._audio.pitch + 1.0)
+        st = int(self._audio.pitch)
+        status = self.query_one("#status", StatusBar)
+        status.pitch = st
+        chatlog = self.query_one("#chatlog", ChatLog)
+        chatlog.write(f"[dim]pitch {st:+d} semitones[/dim]")
+
     # -- config reload --------------------------------------------------------
 
     def _detect_config_changes(
@@ -782,7 +813,7 @@ class TuimbleApp(App):
                 safe.append(f"ptt {key}: {old_ptt[key]} -> {new_ptt[key]}")
 
         # Audio: gains are safe; hardware settings require restart
-        safe_audio = {"input_gain", "output_gain"}
+        safe_audio = {"input_gain", "output_gain", "pitch"}
         old_aud = dataclasses.asdict(old.audio)
         new_aud = dataclasses.asdict(new.audio)
         for key in old_aud:
@@ -809,9 +840,11 @@ class TuimbleApp(App):
 
         self._audio.input_gain = new.audio.input_gain
         self._audio.output_gain = new.audio.output_gain
+        self._audio.pitch = new.audio.pitch
         status = self.query_one("#status", StatusBar)
         status.input_vol = int(new.audio.input_gain * 100)
         status.output_vol = int(new.audio.output_gain * 100)
+        status.pitch = int(new.audio.pitch)
 
     def _apply_restart_changes(self, new: Config) -> None:
         """Apply changes that require reconnect/audio restart."""
@@ -852,6 +885,7 @@ class TuimbleApp(App):
             )
             self._audio.input_gain = acfg.input_gain
             self._audio.output_gain = acfg.output_gain
+            self._audio.pitch = acfg.pitch
             self._config = new
             if self._client.connected:
                 self._start_audio()
@@ -897,6 +931,7 @@ class TuimbleApp(App):
         self._apply_safe_changes(new)
         self._config.audio.input_gain = new.audio.input_gain
         self._config.audio.output_gain = new.audio.output_gain
+        self._config.audio.pitch = new.audio.pitch
 
         if safe:
             for change in safe:

src/tuimble/audio.py

@@ -13,6 +13,8 @@ import queue
 import threading
 from typing import Callable
 
+from tuimble.modulator import PitchShifter
+
 log = logging.getLogger(__name__)
 
 SAMPLE_RATE = 48000
@@ -110,6 +112,7 @@ class AudioPipeline:
         self._deafened = False
         self._input_gain = 1.0
         self._output_gain = 1.0
+        self._pitch_shifter = PitchShifter(sample_rate)
 
     def start(self) -> None:
         """Open audio streams."""
@@ -185,6 +188,14 @@ class AudioPipeline:
     def output_gain(self, value: float):
         self._output_gain = max(0.0, min(2.0, value))
 
+    @property
+    def pitch(self) -> float:
+        return self._pitch_shifter.semitones
+
+    @pitch.setter
+    def pitch(self, value: float):
+        self._pitch_shifter.semitones = value
+
     def _capture_callback(self, indata, frames, time_info, status) -> None:
         """Called by sounddevice when input data is available."""
         if status:
@@ -219,15 +230,20 @@ class AudioPipeline:
     def get_capture_frame(self, timeout: float = 0.0) -> bytes | None:
         """Retrieve next captured PCM frame for transmission.
 
+        Pitch shifting runs here (worker thread) rather than in the
+        PortAudio callback, which must return within the frame period.
+
         Args:
             timeout: Seconds to wait for a frame.  0 returns immediately.
         """
         try:
             if timeout > 0:
-                return self._capture_queue.get(timeout=timeout)
-            return self._capture_queue.get_nowait()
+                pcm = self._capture_queue.get(timeout=timeout)
+            else:
+                pcm = self._capture_queue.get_nowait()
         except queue.Empty:
             return None
+        return self._pitch_shifter.process(pcm)
 
     def queue_playback(self, pcm_data: bytes) -> None:
         """Queue raw PCM data for playback (16-bit, mono, 48kHz)."""

src/tuimble/config.py

@@ -32,6 +32,7 @@ class AudioConfig:
     frame_size: int = 960  # 20ms at 48kHz
     input_gain: float = 1.0
     output_gain: float = 1.0
+    pitch: float = 0.0
 
 
 @dataclass