Add audio streaming via USB microphone

- Neuer Endpunkt GET /audio: ffmpeg liest von plughw:2,0 (USB-Soundkarte CM108)
  und streamt Ogg/Opus mit 16kHz Mono 24kbps
- live.html: Ton-Button (🔇/🔊) startet/stoppt Audio-Stream on demand
- setup.sh: ffmpeg installieren, pi zur audio-Gruppe hinzufügen
- pi zur audio-Gruppe hinzugefügt (war nötig für /dev/snd Zugriff)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/main.py

@@ -104,6 +104,47 @@ def stream():
     )
 
 
+# ---------------------------------------------------------------------------
+# Audio-Stream (Ogg/Opus via ffmpeg)
+# ---------------------------------------------------------------------------
+
+AUDIO_DEVICE = "plughw:2,0"
+AUDIO_SAMPLERATE = 16000
+
+
+def generate_audio():
+    cmd = [
+        "ffmpeg",
+        "-f", "alsa",
+        "-i", AUDIO_DEVICE,
+        "-ar", str(AUDIO_SAMPLERATE),
+        "-ac", "1",
+        "-c:a", "libopus",
+        "-b:a", "24k",
+        "-f", "ogg",
+        "-",
+    ]
+    process = subprocess.Popen(
+        cmd, stdout=subprocess.PIPE, stderr=subprocess.DEVNULL
+    )
+    try:
+        while True:
+            chunk = process.stdout.read(4096)
+            if not chunk:
+                break
+            yield chunk
+    finally:
+        process.kill()
+
+
+@app.route("/audio")
+def audio():
+    return Response(
+        generate_audio(),
+        mimetype="audio/ogg; codecs=opus",
+    )
+
+
 # ---------------------------------------------------------------------------
 # WLAN-Verwaltung
 # ---------------------------------------------------------------------------

app/templates/live.html

@@ -163,9 +163,12 @@
 
 <div id="bottom-bar">
   <div id="clock"></div>
+  <button class="btn" id="audio-btn" onclick="toggleAudio()">🔇 Ton an</button>
   <a class="btn" href="/">⚙ Einstellungen</a>
 </div>
 
+<audio id="audio-stream" src="/audio" preload="none"></audio>
+
 <script>
   // UI bei Tap/Klick kurz einblenden
   let hideTimer;
@@ -190,6 +193,24 @@
   updateClock();
   setInterval(updateClock, 1000);
 
+  // Audio
+  let audioOn = false;
+  function toggleAudio() {
+    const a = document.getElementById("audio-stream");
+    const btn = document.getElementById("audio-btn");
+    if (audioOn) {
+      a.pause();
+      a.src = "";
+      btn.textContent = "🔇 Ton an";
+      audioOn = false;
+    } else {
+      a.src = "/audio";
+      a.play();
+      btn.textContent = "🔊 Ton aus";
+      audioOn = true;
+    }
+  }
+
   // Fullscreen
   function toggleFullscreen() {
     if (!document.fullscreenElement) {

setup.sh

@@ -30,7 +30,8 @@ apt-get install -y \
   rpicam-apps \
   avahi-daemon \
   network-manager \
-  iptables
+  iptables \
+  ffmpeg
 
 # ------------------------------------------------------------------------------
 # 2. Kamera-Interface aktivieren
@@ -50,6 +51,7 @@ info "Verzeichnisse anlegen..."
 mkdir -p /var/lib/babycam
 chown pi:pi /var/lib/babycam
 usermod -aG video pi
+usermod -aG audio pi
 
 info "Projektdateien nach $INSTALL_DIR kopieren..."
 mkdir -p "$INSTALL_DIR"