fix(desktop): capture screen share audio from chosen devices (#3456)

fluxer_desktop/src/main/NativeAudio.ts

@@ -7,6 +7,7 @@ import type {
 	NativeAudioApplication,
 	NativeAudioAvailability,
 	NativeAudioEndReason,
+	NativeAudioPlaybackDevice,
 	NativeAudioStartOptions,
 	NativeAudioStartResult,
 	VirtmicLinkOptions,
@@ -22,7 +23,9 @@ import {
 	isValidAudioFrame,
 	isValidLinuxRule,
 	isValidTargetPid,
+	isValidWinEndpoints,
 	normalizeTimestampUs,
+	resolveWindowsCaptureScope,
 } from '@electron/main/NativeAudioValidation';
 import {ipcMain} from 'electron';
 
@@ -39,6 +42,7 @@ interface NativeCaptureInstance {
 	start(): Promise<void> | void;
 	stop(): Promise<void> | void;
 	setRoutingRule?: (target: {linuxRule: NonNullable<NativeAudioStartOptions['linuxRule']>}) => boolean;
+	setEndpoints?: (endpoints: Array<string>) => boolean;
 }
 
 interface WindowsNativeAudioModule {
@@ -59,12 +63,14 @@ interface WindowsNativeAudioModule {
 	};
 	pidFromHwnd: (hwnd: bigint) => number;
 	resolveAudioRootPid: (pid: number) => number;
+	listPlaybackDevices?: () => Promise<Array<NativeAudioPlaybackDevice>>;
 	ProcessLoopback: new (
 		pid: number,
 		options?: {
 			includeProcessTree?: boolean;
 			captureScope?: 'process' | 'system' | 'session-mixer';
 			winCaptureScope?: 'process' | 'system' | 'session-mixer';
+			endpoints?: Array<string>;
 		},
 	) => NativeCaptureInstance;
 	loadError?: Error | null;
@@ -270,6 +276,7 @@ function loadNativeAudioAddon(): NativeAddonLoadResult {
 							processInclude: false,
 							processExclude: false,
 							sessionMixer: false,
+							endpointSelect: false,
 							systemLoopbackMode: 'unavailable',
 						},
 					},
@@ -290,6 +297,7 @@ function loadNativeAudioAddon(): NativeAddonLoadResult {
 						processInclude,
 						processExclude,
 						sessionMixer,
+						endpointSelect: sessionMixer,
 						systemLoopbackMode:
 							systemLoopbackMode === 'process-exclude' || systemLoopbackMode === 'session-mixer'
 								? systemLoopbackMode
@@ -510,6 +518,21 @@ async function listNativeAudioApplications(): Promise<Array<NativeAudioApplicati
 	}
 }
 
+async function listWindowsPlaybackDevices(): Promise<Array<NativeAudioPlaybackDevice>> {
+	const loadResult = loadNativeAudioAddon();
+	if (loadResult.platform !== 'win32' || !loadResult.availability.available || !loadResult.addon) {
+		return [];
+	}
+	const addon = loadResult.addon as WindowsNativeAudioModule;
+	if (typeof addon.listPlaybackDevices !== 'function') return [];
+	try {
+		return await addon.listPlaybackDevices();
+	} catch (error) {
+		logger.warn('Failed to list Windows playback devices', error);
+		return [];
+	}
+}
+
 async function resolveAudioRootPidForSource(sourceId: unknown): Promise<number | null> {
 	const windowToken = parseDesktopWindowSourceToken(sourceId);
 	if (!windowToken) {
@@ -646,6 +669,19 @@ function reconfigureCaptureById(
 	}
 }
 
+function reconfigureWindowsEndpointsById(senderId: number, captureId: string, endpoints: Array<string>): boolean {
+	const session = activeSessions.get(captureId);
+	if (!session || session.sender.id !== senderId) return false;
+	if (session.finalized || session.stopping) return false;
+	if (typeof session.capture.setEndpoints !== 'function') return false;
+	try {
+		return session.capture.setEndpoints(endpoints);
+	} catch (error) {
+		logger.warn('Failed to change Windows playback devices in place', {captureId, error});
+		return false;
+	}
+}
+
 async function makeRoomForSenderSession(senderId: number): Promise<void> {
 	const senderSessions = activeSessionIdsBySenderId.get(senderId);
 	if (!senderSessions) return;
@@ -679,6 +715,10 @@ async function startNativeAudioCapture(
 				: 'process';
 	const winSystemCapture =
 		loadResult.platform === 'win32' && (winCaptureScope === 'system' || winCaptureScope === 'session-mixer');
+	const winEndpoints = loadResult.platform === 'win32' ? options?.winEndpoints : undefined;
+	if (winEndpoints !== undefined && !isValidWinEndpoints(winEndpoints)) {
+		throw new Error('Invalid Windows playback device selection');
+	}
 	const targetPid = options?.targetPid;
 	if (!options || (!linuxRule && !macSystemCapture && !winSystemCapture && !isValidTargetPid(targetPid))) {
 		throw new Error('Invalid native audio target PID');
@@ -715,13 +755,7 @@ async function startNativeAudioCapture(
 	if (requestedScope === 'system' && availability.capabilities?.systemExcludesSelf !== true) {
 		throw new Error(`Native ${loadResult.platform} system audio capture does not guarantee Fluxer self-exclusion`);
 	}
-	const effectiveWinCaptureScope =
-		loadResult.platform === 'win32' &&
-		winCaptureScope === 'system' &&
-		availability.capabilities?.processExclude === false &&
-		availability.capabilities?.sessionMixer === true
-			? 'session-mixer'
-			: winCaptureScope;
+	const windowsCapture = resolveWindowsCaptureScope(winCaptureScope, winEndpoints, availability.capabilities);
 	if (sender.isDestroyed()) {
 		throw new Error('Cannot start native audio capture for destroyed renderer');
 	}
@@ -739,7 +773,8 @@ async function startNativeAudioCapture(
 		if (!isValidTargetPid(targetPidForCapture)) throw new Error('Invalid native audio target PID');
 		capture = new (loadResult.addon as WindowsNativeAudioModule).ProcessLoopback(targetPidForCapture, {
 			includeProcessTree: winSystemCapture ? false : (options.includeProcessTree ?? true),
-			captureScope: effectiveWinCaptureScope,
+			captureScope: windowsCapture.captureScope,
+			...(windowsCapture.endpoints ? {endpoints: windowsCapture.endpoints} : {}),
 		});
 	} else if (loadResult.platform === 'darwin') {
 		if (!isValidTargetPid(targetPidForCapture)) throw new Error('Invalid native audio target PID');
@@ -883,6 +918,16 @@ export function registerNativeAudioHandlers(): void {
 			return reconfigureCaptureById(event.sender.id, captureId, linuxRule);
 		},
 	);
+	ipcMain.handle('native-audio:set-win-endpoints', (event, captureId: unknown, endpoints: unknown): boolean => {
+		if (typeof captureId !== 'string' || !isValidWinEndpoints(endpoints)) {
+			return false;
+		}
+		return reconfigureWindowsEndpointsById(event.sender.id, captureId, endpoints);
+	});
+	ipcMain.handle(
+		'native-audio:list-playback-devices',
+		(): Promise<Array<NativeAudioPlaybackDevice>> => listWindowsPlaybackDevices(),
+	);
 	ipcMain.handle('native-audio:stop', async (event, captureId: string): Promise<void> => {
 		const session = activeSessions.get(captureId);
 		if (!session || session.sender.id !== event.sender.id) {
@@ -899,6 +944,8 @@ export function cleanupNativeAudio(): void {
 	ipcMain.removeHandler('native-audio:resolve-root-pid');
 	ipcMain.removeHandler('native-audio:start');
 	ipcMain.removeHandler('native-audio:set-rule');
+	ipcMain.removeHandler('native-audio:set-win-endpoints');
+	ipcMain.removeHandler('native-audio:list-playback-devices');
 	ipcMain.removeHandler('native-audio:stop');
 	handlersRegistered = false;
 	for (const session of [...activeSessions.values()]) {