Add audio channel selection (mono/left/right), show device LED count in target editor

Audio capture now produces per-channel FFT spectrum and RMS alongside
the existing mono mix. Each audio color strip source can select which
channel to visualize via a new "Channel" dropdown. This enables stereo
setups with separate left/right segments on the same LED strip.

Also shows the device LED count under the device selector in the target
editor for quick reference.

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

server/src/wled_controller/api/routes/color_strip_sources.py

@@ -83,6 +83,7 @@ def _css_to_response(source, overlay_active: bool = False) -> ColorStripSourceRe
         visualization_mode=getattr(source, "visualization_mode", None),
         audio_device_index=getattr(source, "audio_device_index", None),
         audio_loopback=getattr(source, "audio_loopback", None),
+        audio_channel=getattr(source, "audio_channel", None),
         sensitivity=getattr(source, "sensitivity", None),
         color_peak=getattr(source, "color_peak", None),
         overlay_active=overlay_active,
@@ -164,6 +165,7 @@ async def create_color_strip_source(
             visualization_mode=data.visualization_mode,
             audio_device_index=data.audio_device_index,
             audio_loopback=data.audio_loopback,
+            audio_channel=data.audio_channel,
             sensitivity=data.sensitivity,
             color_peak=data.color_peak,
         )
@@ -237,6 +239,7 @@ async def update_color_strip_source(
             visualization_mode=data.visualization_mode,
             audio_device_index=data.audio_device_index,
             audio_loopback=data.audio_loopback,
+            audio_channel=data.audio_channel,
             sensitivity=data.sensitivity,
             color_peak=data.color_peak,
         )

server/src/wled_controller/api/schemas/color_strip_sources.py

@@ -71,6 +71,7 @@ class ColorStripSourceCreate(BaseModel):
     audio_loopback: Optional[bool] = Field(None, description="True for system audio (WASAPI loopback), False for mic/line-in")
     sensitivity: Optional[float] = Field(None, description="Audio sensitivity/gain 0.1-5.0", ge=0.1, le=5.0)
     color_peak: Optional[List[int]] = Field(None, description="Peak/high RGB color for VU meter [R,G,B]")
+    audio_channel: Optional[str] = Field(None, description="Audio channel: mono|left|right")
     # shared
     led_count: int = Field(default=0, description="Total LED count (0 = auto from calibration / device)", ge=0)
     description: Optional[str] = Field(None, description="Optional description", max_length=500)
@@ -112,6 +113,7 @@ class ColorStripSourceUpdate(BaseModel):
     audio_loopback: Optional[bool] = Field(None, description="True for system audio (WASAPI loopback), False for mic/line-in")
     sensitivity: Optional[float] = Field(None, description="Audio sensitivity/gain 0.1-5.0", ge=0.1, le=5.0)
     color_peak: Optional[List[int]] = Field(None, description="Peak/high RGB color for VU meter [R,G,B]")
+    audio_channel: Optional[str] = Field(None, description="Audio channel: mono|left|right")
     # shared
     led_count: Optional[int] = Field(None, description="Total LED count (0 = auto from calibration / device)", ge=0)
     description: Optional[str] = Field(None, description="Optional description", max_length=500)
@@ -155,6 +157,7 @@ class ColorStripSourceResponse(BaseModel):
     audio_loopback: Optional[bool] = Field(None, description="WASAPI loopback mode")
     sensitivity: Optional[float] = Field(None, description="Audio sensitivity")
     color_peak: Optional[List[int]] = Field(None, description="Peak color [R,G,B]")
+    audio_channel: Optional[str] = Field(None, description="Audio channel: mono|left|right")
     # shared
     led_count: int = Field(0, description="Total LED count (0 = auto from calibration / device)")
     description: Optional[str] = Field(None, description="Description")

server/src/wled_controller/core/audio/audio_capture.py

@@ -37,14 +37,23 @@ class AudioAnalysis:
     """Snapshot of audio analysis results.
 
     Written by the capture thread, read by visualization streams.
+    Mono fields contain the mixed-down signal (all channels averaged).
+    Per-channel fields (left/right) are populated when the source is stereo+.
+    For mono sources, left/right are copies of the mono data.
     """
 
     timestamp: float = 0.0
+    # Mono (mixed) — backward-compatible fields
     rms: float = 0.0
     peak: float = 0.0
     spectrum: np.ndarray = field(default_factory=lambda: np.zeros(NUM_BANDS, dtype=np.float32))
     beat: bool = False
     beat_intensity: float = 0.0
+    # Per-channel
+    left_rms: float = 0.0
+    left_spectrum: np.ndarray = field(default_factory=lambda: np.zeros(NUM_BANDS, dtype=np.float32))
+    right_rms: float = 0.0
+    right_spectrum: np.ndarray = field(default_factory=lambda: np.zeros(NUM_BANDS, dtype=np.float32))
 
 
 # ---------------------------------------------------------------------------
@@ -111,6 +120,8 @@ class AudioCaptureStream:
 
         # Smoothed spectrum (exponential decay between frames)
         self._smooth_spectrum = np.zeros(NUM_BANDS, dtype=np.float32)
+        self._smooth_spectrum_left = np.zeros(NUM_BANDS, dtype=np.float32)
+        self._smooth_spectrum_right = np.zeros(NUM_BANDS, dtype=np.float32)
 
     def start(self) -> None:
         if self._running:
@@ -196,6 +207,8 @@ class AudioCaptureStream:
             )
 
             spectrum_buf = np.zeros(NUM_BANDS, dtype=np.float32)
+            spectrum_buf_left = np.zeros(NUM_BANDS, dtype=np.float32)
+            spectrum_buf_right = np.zeros(NUM_BANDS, dtype=np.float32)
 
             while self._running:
                 try:
@@ -206,45 +219,49 @@ class AudioCaptureStream:
                     time.sleep(0.05)
                     continue
 
-                # Mix to mono if multi-channel
+                # Split channels and mix to mono
                 if channels > 1:
                     data = data.reshape(-1, channels)
+                    left_samples = data[:, 0].copy()
+                    right_samples = data[:, 1].copy() if channels >= 2 else left_samples.copy()
                     samples = data.mean(axis=1).astype(np.float32)
                 else:
                     samples = data
+                    left_samples = samples
+                    right_samples = samples
 
-                # RMS and peak
+                # RMS and peak (mono)
                 rms = float(np.sqrt(np.mean(samples ** 2)))
                 peak = float(np.max(np.abs(samples)))
+                left_rms = float(np.sqrt(np.mean(left_samples ** 2)))
+                right_rms = float(np.sqrt(np.mean(right_samples ** 2)))
 
-                # FFT
+                # FFT helper
-                chunk = samples[: self._chunk_size]
+                alpha = 0.3  # smoothing factor (lower = smoother)
+
+                def _fft_bands(samps, buf, smooth_buf):
+                    chunk = samps[: self._chunk_size]
                     if len(chunk) < self._chunk_size:
                         chunk = np.pad(chunk, (0, self._chunk_size - len(chunk)))
                     windowed = chunk * self._window
                     fft_mag = np.abs(np.fft.rfft(windowed))
-                # Normalize by chunk size
                     fft_mag /= self._chunk_size
-
+                    for b, (s, e) in enumerate(self._bands):
-                # Bin into logarithmic bands
+                        if s < len(fft_mag) and e <= len(fft_mag):
-                for b, (start, end) in enumerate(self._bands):
+                            buf[b] = float(np.mean(fft_mag[s:e]))
-                    if start < len(fft_mag) and end <= len(fft_mag):
-                        spectrum_buf[b] = float(np.mean(fft_mag[start:end]))
                         else:
-                        spectrum_buf[b] = 0.0
+                            buf[b] = 0.0
-
+                    spec_max = float(np.max(buf))
-                # Normalize spectrum to 0-1 range (adaptive)
-                spec_max = float(np.max(spectrum_buf))
                     if spec_max > 1e-6:
-                    spectrum_buf /= spec_max
+                        buf /= spec_max
+                    smooth_buf[:] = alpha * buf + (1.0 - alpha) * smooth_buf
 
-                # Exponential smoothing
+                # Compute FFT for mono, left, right
-                alpha = 0.3  # smoothing factor (lower = smoother)
+                _fft_bands(samples, spectrum_buf, self._smooth_spectrum)
-                self._smooth_spectrum[:] = (
+                _fft_bands(left_samples, spectrum_buf_left, self._smooth_spectrum_left)
-                    alpha * spectrum_buf + (1.0 - alpha) * self._smooth_spectrum
+                _fft_bands(right_samples, spectrum_buf_right, self._smooth_spectrum_right)
-                )
 
-                # Beat detection — compare current energy to rolling average
+                # Beat detection — compare current energy to rolling average (mono)
                 energy = float(np.sum(samples ** 2))
                 self._energy_history[self._energy_idx % len(self._energy_history)] = energy
                 self._energy_idx += 1
@@ -265,6 +282,10 @@ class AudioCaptureStream:
                     spectrum=self._smooth_spectrum.copy(),
                     beat=beat,
                     beat_intensity=beat_intensity,
+                    left_rms=left_rms,
+                    left_spectrum=self._smooth_spectrum_left.copy(),
+                    right_rms=right_rms,
+                    right_spectrum=self._smooth_spectrum_right.copy(),
                 )
 
                 with self._lock:

server/src/wled_controller/core/processing/audio_stream.py

@@ -68,6 +68,7 @@ class AudioColorStripStream(ColorStripStream):
         self._auto_size = not source.led_count
         self._led_count = source.led_count if source.led_count and source.led_count > 0 else 1
         self._mirror = bool(getattr(source, "mirror", False))
+        self._audio_channel = getattr(source, "audio_channel", "mono")  # mono | left | right
         with self._colors_lock:
             self._colors: Optional[np.ndarray] = None
 
@@ -193,6 +194,16 @@ class AudioColorStripStream(ColorStripStream):
                 elapsed = time.perf_counter() - loop_start
                 time.sleep(max(frame_time - elapsed, 0.001))
 
+    # ── Channel selection ─────────────────────────────────────────
+
+    def _pick_channel(self, analysis):
+        """Return (spectrum, rms) for the configured audio channel."""
+        if self._audio_channel == "left":
+            return analysis.left_spectrum, analysis.left_rms
+        elif self._audio_channel == "right":
+            return analysis.right_spectrum, analysis.right_rms
+        return analysis.spectrum, analysis.rms
+
     # ── Spectrum Analyzer ──────────────────────────────────────────
 
     def _render_spectrum(self, buf: np.ndarray, n: int, analysis) -> None:
@@ -200,7 +211,7 @@ class AudioColorStripStream(ColorStripStream):
             buf[:] = 0
             return
 
-        spectrum = analysis.spectrum
+        spectrum, _ = self._pick_channel(analysis)
         sensitivity = self._sensitivity
         smoothing = self._smoothing
         lut = self._palette_lut
@@ -249,7 +260,8 @@ class AudioColorStripStream(ColorStripStream):
             buf[:] = 0
             return
 
-        rms = analysis.rms * self._sensitivity
+        _, ch_rms = self._pick_channel(analysis)
+        rms = ch_rms * self._sensitivity
         # Temporal smoothing on RMS
         rms = self._smoothing * self._prev_rms + (1.0 - self._smoothing) * rms
         self._prev_rms = rms

server/src/wled_controller/static/css/modal.css

@@ -240,6 +240,13 @@
     background: var(--card-bg, #1e1e1e);
 }
 
+.device-led-info {
+    display: block;
+    margin-top: 4px;
+    color: var(--text-muted, #888);
+    font-size: 0.85em;
+}
+
 .segment-row-header {
     display: flex;
     justify-content: space-between;

server/src/wled_controller/static/js/features/color-strips.js

@@ -438,6 +438,7 @@ function _loadAudioState(css) {
     document.getElementById('css-editor-audio-smoothing').value = smoothing;
     document.getElementById('css-editor-audio-smoothing-val').textContent = parseFloat(smoothing).toFixed(2);
 
+    document.getElementById('css-editor-audio-channel').value = css.audio_channel || 'mono';
     document.getElementById('css-editor-audio-palette').value = css.palette || 'rainbow';
     document.getElementById('css-editor-audio-color').value = rgbArrayToHex(css.color || [0, 255, 0]);
     document.getElementById('css-editor-audio-color-peak').value = rgbArrayToHex(css.color_peak || [255, 0, 0]);
@@ -461,6 +462,7 @@ function _resetAudioState() {
     document.getElementById('css-editor-audio-sensitivity-val').textContent = '1.0';
     document.getElementById('css-editor-audio-smoothing').value = 0.3;
     document.getElementById('css-editor-audio-smoothing-val').textContent = '0.30';
+    document.getElementById('css-editor-audio-channel').value = 'mono';
     document.getElementById('css-editor-audio-palette').value = 'rainbow';
     document.getElementById('css-editor-audio-color').value = '#00ff00';
     document.getElementById('css-editor-audio-color-peak').value = '#ff0000';
@@ -544,9 +546,12 @@ export function createColorStripCard(source, pictureSourceMap) {
     } else if (isAudio) {
         const vizLabel = t('color_strip.audio.viz.' + (source.visualization_mode || 'spectrum')) || source.visualization_mode || 'spectrum';
         const sensitivityVal = (source.sensitivity || 1.0).toFixed(1);
+        const ch = source.audio_channel || 'mono';
+        const chBadge = ch !== 'mono' ? `<span class="stream-card-prop" title="${t('color_strip.audio.channel')}">${ch === 'left' ? 'L' : 'R'}</span>` : '';
         propsHtml = `
             <span class="stream-card-prop">🎵 ${escapeHtml(vizLabel)}</span>
             <span class="stream-card-prop" title="${t('color_strip.audio.sensitivity')}">📶 ${sensitivityVal}</span>
+            ${chBadge}
             ${source.mirror ? `<span class="stream-card-prop">🪞</span>` : ''}
         `;
     } else {
@@ -808,6 +813,7 @@ export async function saveCSSEditor() {
             visualization_mode: document.getElementById('css-editor-audio-viz').value,
             audio_device_index: parseInt(devIdx) || -1,
             audio_loopback: devLoop !== '0',
+            audio_channel: document.getElementById('css-editor-audio-channel').value,
             sensitivity: parseFloat(document.getElementById('css-editor-audio-sensitivity').value),
             smoothing: parseFloat(document.getElementById('css-editor-audio-smoothing').value),
             palette: document.getElementById('css-editor-audio-palette').value,

server/src/wled_controller/static/js/features/targets.js

@@ -140,6 +140,18 @@ function _updateFpsRecommendation() {
     }
 }
 
+function _updateDeviceInfo() {
+    const deviceSelect = document.getElementById('target-editor-device');
+    const el = document.getElementById('target-editor-device-info');
+    const device = _targetEditorDevices.find(d => d.id === deviceSelect.value);
+    if (device && device.led_count) {
+        el.textContent = `${device.led_count} LEDs`;
+        el.style.display = '';
+    } else {
+        el.style.display = 'none';
+    }
+}
+
 function _updateKeepaliveVisibility() {
     const deviceSelect = document.getElementById('target-editor-device');
     const keepaliveGroup = document.getElementById('target-editor-keepalive-group');
@@ -267,10 +279,11 @@ export async function showTargetEditor(targetId = null) {
         _targetNameManuallyEdited = !!targetId;
         document.getElementById('target-editor-name').oninput = () => { _targetNameManuallyEdited = true; };
         window._targetAutoName = _autoGenerateTargetName;
-        deviceSelect.onchange = () => { _updateKeepaliveVisibility(); _updateFpsRecommendation(); _autoGenerateTargetName(); };
+        deviceSelect.onchange = () => { _updateDeviceInfo(); _updateKeepaliveVisibility(); _updateFpsRecommendation(); _autoGenerateTargetName(); };
         if (!targetId) _autoGenerateTargetName();
 
         // Show/hide standby interval based on selected device capabilities
+        _updateDeviceInfo();
         _updateKeepaliveVisibility();
         _updateFpsRecommendation();
 

server/src/wled_controller/static/locales/en.json

@@ -667,6 +667,11 @@
   "color_strip.audio.viz.vu_meter": "VU Meter",
   "color_strip.audio.device": "Audio Device:",
   "color_strip.audio.device.hint": "Audio input source. Loopback devices capture system audio output; input devices capture microphone or line-in.",
+  "color_strip.audio.channel": "Channel:",
+  "color_strip.audio.channel.hint": "Select which audio channel to visualize. Use Left/Right for stereo setups.",
+  "color_strip.audio.channel.mono": "Mono (L+R mix)",
+  "color_strip.audio.channel.left": "Left",
+  "color_strip.audio.channel.right": "Right",
   "color_strip.audio.sensitivity": "Sensitivity:",
   "color_strip.audio.sensitivity.hint": "Gain multiplier for audio levels. Higher values make LEDs react to quieter sounds.",
   "color_strip.audio.smoothing": "Smoothing:",

server/src/wled_controller/static/locales/ru.json

@@ -667,6 +667,11 @@
   "color_strip.audio.viz.vu_meter": "VU-метр",
   "color_strip.audio.device": "Аудиоустройство:",
   "color_strip.audio.device.hint": "Источник аудиосигнала. Устройства обратной петли захватывают системный звук; устройства ввода — микрофон или линейный вход.",
+  "color_strip.audio.channel": "Канал:",
+  "color_strip.audio.channel.hint": "Какой аудиоканал визуализировать. Используйте Левый/Правый для стерео-режима.",
+  "color_strip.audio.channel.mono": "Моно (Л+П микс)",
+  "color_strip.audio.channel.left": "Левый",
+  "color_strip.audio.channel.right": "Правый",
   "color_strip.audio.sensitivity": "Чувствительность:",
   "color_strip.audio.sensitivity.hint": "Множитель усиления аудиосигнала. Более высокие значения делают LED чувствительнее к тихим звукам.",
   "color_strip.audio.smoothing": "Сглаживание:",

server/src/wled_controller/storage/color_strip_source.py

@@ -78,6 +78,7 @@ class ColorStripSource:
             "audio_loopback": None,
             "sensitivity": None,
             "color_peak": None,
+            "audio_channel": None,
         }
 
     @staticmethod
@@ -165,6 +166,7 @@ class ColorStripSource:
                 visualization_mode=data.get("visualization_mode") or "spectrum",
                 audio_device_index=int(data.get("audio_device_index", -1)),
                 audio_loopback=bool(data.get("audio_loopback", True)),
+                audio_channel=data.get("audio_channel") or "mono",
                 sensitivity=float(data.get("sensitivity") or 1.0),
                 smoothing=float(data.get("smoothing") or 0.3),
                 palette=data.get("palette") or "rainbow",
@@ -366,6 +368,7 @@ class AudioColorStripSource(ColorStripSource):
     visualization_mode: str = "spectrum"    # spectrum | beat_pulse | vu_meter
     audio_device_index: int = -1            # -1 = default input device
     audio_loopback: bool = True             # True = WASAPI loopback (system audio)
+    audio_channel: str = "mono"             # mono | left | right
     sensitivity: float = 1.0                # gain multiplier (0.1–5.0)
     smoothing: float = 0.3                  # temporal smoothing (0.0–1.0)
     palette: str = "rainbow"                # named color palette
@@ -379,6 +382,7 @@ class AudioColorStripSource(ColorStripSource):
         d["visualization_mode"] = self.visualization_mode
         d["audio_device_index"] = self.audio_device_index
         d["audio_loopback"] = self.audio_loopback
+        d["audio_channel"] = self.audio_channel
         d["sensitivity"] = self.sensitivity
         d["smoothing"] = self.smoothing
         d["palette"] = self.palette

server/src/wled_controller/storage/color_strip_store.py

@@ -122,6 +122,7 @@ class ColorStripStore:
         visualization_mode: str = "spectrum",
         audio_device_index: int = -1,
         audio_loopback: bool = True,
+        audio_channel: str = "mono",
         sensitivity: float = 1.0,
         color_peak: Optional[list] = None,
     ) -> ColorStripSource:
@@ -215,6 +216,7 @@ class ColorStripStore:
                 visualization_mode=visualization_mode or "spectrum",
                 audio_device_index=audio_device_index if audio_device_index is not None else -1,
                 audio_loopback=bool(audio_loopback),
+                audio_channel=audio_channel or "mono",
                 sensitivity=float(sensitivity) if sensitivity else 1.0,
                 smoothing=float(smoothing) if smoothing else 0.3,
                 palette=palette or "rainbow",
@@ -292,6 +294,7 @@ class ColorStripStore:
         visualization_mode: Optional[str] = None,
         audio_device_index: Optional[int] = None,
         audio_loopback: Optional[bool] = None,
+        audio_channel: Optional[str] = None,
         sensitivity: Optional[float] = None,
         color_peak: Optional[list] = None,
     ) -> ColorStripSource:
@@ -381,6 +384,8 @@ class ColorStripStore:
                 source.audio_device_index = audio_device_index
             if audio_loopback is not None:
                 source.audio_loopback = bool(audio_loopback)
+            if audio_channel is not None:
+                source.audio_channel = audio_channel
             if sensitivity is not None:
                 source.sensitivity = float(sensitivity)
             if smoothing is not None:

server/src/wled_controller/templates/modals/css-editor.html

@@ -342,6 +342,19 @@
                         </select>
                     </div>
 
+                    <div class="form-group">
+                        <div class="label-row">
+                            <label for="css-editor-audio-channel" data-i18n="color_strip.audio.channel">Channel:</label>
+                            <button type="button" class="hint-toggle" onclick="toggleHint(this)" title="?" data-i18n-aria-label="aria.hint">?</button>
+                        </div>
+                        <small class="input-hint" style="display:none" data-i18n="color_strip.audio.channel.hint">Select which audio channel to visualize. Use Left/Right for stereo setups.</small>
+                        <select id="css-editor-audio-channel">
+                            <option value="mono" data-i18n="color_strip.audio.channel.mono">Mono (L+R mix)</option>
+                            <option value="left" data-i18n="color_strip.audio.channel.left">Left</option>
+                            <option value="right" data-i18n="color_strip.audio.channel.right">Right</option>
+                        </select>
+                    </div>
+
                     <div class="form-group">
                         <div class="label-row">
                             <label for="css-editor-audio-sensitivity">

server/src/wled_controller/templates/modals/target-editor.html

@@ -21,6 +21,7 @@
                     </div>
                     <small class="input-hint" style="display:none" data-i18n="targets.device.hint">Select the LED device to send data to</small>
                     <select id="target-editor-device"></select>
+                    <small id="target-editor-device-info" class="device-led-info" style="display:none"></small>
                 </div>
 
                 <div class="form-group" id="target-editor-segments-group">