Merge 04dd37f58f into 317218a682

audio.go

@@ -80,7 +80,7 @@ func startAudioSubprocesses() error {
 			[]string{
 				"ALSA_CAPTURE_DEVICE=" + alsaDevice,
 				"OPUS_BITRATE=128000",
-				"OPUS_COMPLEXITY=5",
+				"OPUS_COMPLEXITY=2",
 			},
 		)
 

config.go

@@ -160,11 +160,10 @@ var defaultConfig = &Config{
 		RelativeMouse: true,
 		Keyboard:      true,
 		MassStorage:   true,
-		Audio:         true,
 	},
 	NetworkConfig:     &network.NetworkConfig{},
 	DefaultLogLevel:   "INFO",
-	AudioOutputSource: "usb",
+	AudioOutputSource: "hdmi",
 }
 
 var (

internal/audio/c/audio.c

@@ -55,20 +55,20 @@ static uint8_t channels = 2;
 static uint16_t frame_size = 960;  // 20ms frames at 48kHz
 
 static uint32_t opus_bitrate = 128000;
-static uint8_t opus_complexity = 5;  // Higher complexity for better quality
+static uint8_t opus_complexity = 2;
 static uint16_t max_packet_size = 1500;
 
 // Opus encoder constants (hardcoded for production)
 #define OPUS_VBR 1                      // VBR enabled
-#define OPUS_VBR_CONSTRAINT 1           // Constrained VBR (prevents bitrate starvation at low volumes)
+#define OPUS_VBR_CONSTRAINT 0           // Unconstrained VBR (better for low-volume signals)
 #define OPUS_SIGNAL_TYPE 3002           // OPUS_SIGNAL_MUSIC (better transient handling)
-#define OPUS_BANDWIDTH 1104             // OPUS_BANDWIDTH_SUPERWIDEBAND (16kHz)
+#define OPUS_BANDWIDTH 1105             // OPUS_BANDWIDTH_FULLBAND (20kHz, enabled by 128kbps bitrate)
-#define OPUS_DTX 1                      // DTX enabled (bandwidth optimization)
+#define OPUS_DTX 0                      // DTX disabled (prevents audio drops)
 #define OPUS_LSB_DEPTH 16               // 16-bit depth
 
 // ALSA retry configuration
 static uint32_t sleep_microseconds = 1000;
-static uint32_t sleep_milliseconds = 1;
+static uint32_t sleep_milliseconds = 1;  // Precomputed: sleep_microseconds / 1000
 static uint8_t max_attempts_global = 5;
 static uint32_t max_backoff_us_global = 500000;
 
@@ -283,7 +283,7 @@ static int configure_alsa_device(snd_pcm_t *handle, const char *device_name) {
 	err = snd_pcm_hw_params_set_period_size_near(handle, params, &period_size, 0);
 	if (err < 0) return err;
 
-	snd_pcm_uframes_t buffer_size = period_size * 4;  // 4 periods = 80ms buffer for stability
+	snd_pcm_uframes_t buffer_size = period_size * 2;  // Optimized: minimal buffer for low latency
 	err = snd_pcm_hw_params_set_buffer_size_near(handle, params, &buffer_size);
 	if (err < 0) return err;
 
@@ -471,6 +471,72 @@ retry_read:
 		simd_clear_samples_s16(&pcm_buffer[pcm_rc * channels], remaining_samples);
 	}
 
+	// Find peak amplitude with NEON SIMD
+	uint32_t total_samples = frame_size * channels;
+	int16x8_t vmax = vdupq_n_s16(0);
+
+	uint32_t i;
+	for (i = 0; i + 8 <= total_samples; i += 8) {
+		int16x8_t v = vld1q_s16(&pcm_buffer[i]);
+		int16x8_t vabs = vabsq_s16(v);
+		vmax = vmaxq_s16(vmax, vabs);
+	}
+
+	// Horizontal max reduction (manual for ARMv7)
+	int16x4_t vmax_low = vget_low_s16(vmax);
+	int16x4_t vmax_high = vget_high_s16(vmax);
+	int16x4_t vmax_reduced = vmax_s16(vmax_low, vmax_high);
+	vmax_reduced = vpmax_s16(vmax_reduced, vmax_reduced);
+	vmax_reduced = vpmax_s16(vmax_reduced, vmax_reduced);
+	int16_t peak = vget_lane_s16(vmax_reduced, 0);
+
+	// Handle remaining samples
+	for (; i < total_samples; i++) {
+		int16_t abs_val = (pcm_buffer[i] < 0) ? -pcm_buffer[i] : pcm_buffer[i];
+		if (abs_val > peak) peak = abs_val;
+	}
+
+	// Apply gain if signal is weak (below -18dB = 4096) but above noise floor
+	// Noise gate: only apply gain if peak > 256 (below this is likely just noise)
+	// Target: boost to ~50% of range (16384) to improve SNR
+	if (peak > 256 && peak < 4096) {
+		float gain = 16384.0f / peak;
+		if (gain > 8.0f) gain = 8.0f;  // Max 18dB boost
+
+		// Apply gain with NEON and saturation
+		float32x4_t vgain = vdupq_n_f32(gain);
+		for (i = 0; i + 8 <= total_samples; i += 8) {
+			int16x8_t v = vld1q_s16(&pcm_buffer[i]);
+
+			// Convert to float, apply gain, saturate back to int16
+			int32x4_t v_low = vmovl_s16(vget_low_s16(v));
+			int32x4_t v_high = vmovl_s16(vget_high_s16(v));
+
+			float32x4_t f_low = vcvtq_f32_s32(v_low);
+			float32x4_t f_high = vcvtq_f32_s32(v_high);
+
+			f_low = vmulq_f32(f_low, vgain);
+			f_high = vmulq_f32(f_high, vgain);
+
+			v_low = vcvtq_s32_f32(f_low);
+			v_high = vcvtq_s32_f32(f_high);
+
+			// Saturate to int16 range
+			int16x4_t result_low = vqmovn_s32(v_low);
+			int16x4_t result_high = vqmovn_s32(v_high);
+
+			vst1q_s16(&pcm_buffer[i], vcombine_s16(result_low, result_high));
+		}
+
+		// Handle remaining samples
+		for (; i < total_samples; i++) {
+			int32_t boosted = (int32_t)(pcm_buffer[i] * gain);
+			if (boosted > 32767) boosted = 32767;
+			if (boosted < -32768) boosted = -32768;
+			pcm_buffer[i] = (int16_t)boosted;
+		}
+	}
+
 	nb_bytes = opus_encode(encoder, pcm_buffer, frame_size, out, max_packet_size);
 	return nb_bytes;
 }

ui/src/components/popovers/AudioPopover.tsx

@@ -10,7 +10,7 @@ import notifications from "@/notifications";
 
 export default function AudioPopover() {
   const { send } = useJsonRpc();
-  const [audioOutputSource, setAudioOutputSource] = useState<string>("usb");
+  const [audioOutputSource, setAudioOutputSource] = useState<string>("hdmi");
   const [audioOutputEnabled, setAudioOutputEnabled] = useState<boolean>(true);
   const [audioInputEnabled, setAudioInputEnabled] = useState<boolean>(true);
   const [usbAudioEnabled, setUsbAudioEnabled] = useState<boolean>(false);

ui/src/routes/devices.$id.tsx

@@ -191,7 +191,7 @@ export default function KvmIdRoute() {
           console.warn("[SDP] Opus 48kHz stereo not found in answer - stereo may not work");
         } else {
           const pt = opusMatch[1];
-          const stereoParams = 'stereo=1;sprop-stereo=1;maxaveragebitrate=128000;usedtx=1;useinbandfec=1';
+          const stereoParams = 'stereo=1;sprop-stereo=1;maxaveragebitrate=128000';
           const fmtpRegex = new RegExp(`a=fmtp:${pt}\\s+(.+)`, 'i');
           const fmtpMatch = remoteDescription.sdp.match(fmtpRegex);
 
@@ -463,7 +463,7 @@ export default function KvmIdRoute() {
             console.warn("[SDP] Opus 48kHz stereo not found in offer - stereo may not work");
           } else {
             const pt = opusMatch[1];
-            const stereoParams = 'stereo=1;sprop-stereo=1;maxaveragebitrate=128000;usedtx=1;useinbandfec=1';
+            const stereoParams = 'stereo=1;sprop-stereo=1;maxaveragebitrate=128000';
             const fmtpRegex = new RegExp(`a=fmtp:${pt}\\s+(.+)`, 'i');
             const fmtpMatch = offer.sdp.match(fmtpRegex);