refactor: Update default and YouTube video formats for compatibility

backend/src/__tests__/services/downloaders/YtDlpDownloader.safari.test.ts

@@ -0,0 +1,103 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+// Mock dependencies
+const mockExecuteYtDlpSpawn = vi.fn();
+const mockExecuteYtDlpJson = vi.fn().mockResolvedValue({
+    title: 'Test Video',
+    uploader: 'Test Author',
+    upload_date: '20230101',
+    thumbnail: 'http://example.com/thumb.jpg',
+    extractor: 'youtube'
+});
+const mockGetUserYtDlpConfig = vi.fn().mockReturnValue({});
+
+vi.mock('../../../utils/ytDlpUtils', () => ({
+    executeYtDlpSpawn: (...args: any[]) => mockExecuteYtDlpSpawn(...args),
+    executeYtDlpJson: (...args: any[]) => mockExecuteYtDlpJson(...args),
+    getUserYtDlpConfig: (...args: any[]) => mockGetUserYtDlpConfig(...args),
+    getNetworkConfigFromUserConfig: () => ({})
+}));
+
+vi.mock('../../../services/storageService', () => ({
+    updateActiveDownload: vi.fn(),
+    saveVideo: vi.fn(),
+    getVideoBySourceUrl: vi.fn(),
+    updateVideo: vi.fn(),
+}));
+
+vi.mock('fs-extra', () => ({
+    default: {
+        pathExists: vi.fn().mockResolvedValue(false),
+        ensureDirSync: vi.fn(),
+        existsSync: vi.fn().mockReturnValue(false),
+        createWriteStream: vi.fn().mockReturnValue({
+            on: (event: string, cb: any) => {
+                if (event === 'finish') cb();
+                return { on: () => {} };
+            }
+        }),
+        readdirSync: vi.fn().mockReturnValue([]),
+    }
+}));
+
+vi.mock('axios', () => ({
+    default: {
+        get: vi.fn().mockResolvedValue({ data: {} }),
+        create: vi.fn().mockReturnValue({ get: vi.fn(), post: vi.fn() }),
+    }
+}));
+
+import { YtDlpDownloader } from '../../../services/downloaders/YtDlpDownloader';
+
+describe('YtDlpDownloader Safari Compatibility', () => {
+    beforeEach(() => {
+        vi.clearAllMocks();
+        mockExecuteYtDlpSpawn.mockReturnValue({
+            stdout: { on: vi.fn() },
+            kill: vi.fn(),
+            then: (resolve: any) => resolve()
+        });
+    });
+
+    it('should use H.264 compatible format for YouTube videos by default', async () => {
+        await YtDlpDownloader.downloadVideo('https://www.youtube.com/watch?v=123456');
+
+        expect(mockExecuteYtDlpSpawn).toHaveBeenCalledTimes(1);
+        const args = mockExecuteYtDlpSpawn.mock.calls[0][1];
+        
+        expect(args.format).toContain('vcodec^=avc1');
+        // Expect m4a audio which implies AAC for YouTube
+        expect(args.format).toContain('ext=m4a');
+    });
+
+    it('should maintain H.264 preference even when formatSort is provided', async () => {
+        // Mock user config with formatSort
+        mockGetUserYtDlpConfig.mockReturnValue({
+            S: 'res:1080'
+        });
+
+        await YtDlpDownloader.downloadVideo('https://www.youtube.com/watch?v=123456');
+
+        expect(mockExecuteYtDlpSpawn).toHaveBeenCalledTimes(1);
+        const args = mockExecuteYtDlpSpawn.mock.calls[0][1];
+        
+        // Should have both formatSort AND the specific format
+        expect(args.formatSort).toBe('res:1080');
+        expect(args.format).toContain('vcodec^=avc1');
+    });
+
+    it('should NOT force generic avc1 string if user provides custom format', async () => {
+        // Mock user config with custom format
+        mockGetUserYtDlpConfig.mockReturnValue({
+            f: 'bestvideo+bestaudio'
+        });
+
+        await YtDlpDownloader.downloadVideo('https://www.youtube.com/watch?v=123456');
+
+        expect(mockExecuteYtDlpSpawn).toHaveBeenCalledTimes(1);
+        const args = mockExecuteYtDlpSpawn.mock.calls[0][1];
+        
+        // Should use user's format
+        expect(args.format).toBe('bestvideo+bestaudio');
+    });
+});

backend/src/services/downloaders/YtDlpDownloader.ts

@@ -336,9 +336,9 @@ export class YtDlpDownloader {
 
       // Default format based on user config or fallback
       let defaultFormat =
-        "bestvideo[ext=mp4]+bestaudio[ext=m4a]/best[ext=mp4]/best";
+        "bestvideo[ext=mp4][vcodec^=avc1]+bestaudio[ext=m4a]/best[ext=mp4]/best";
       let youtubeFormat =
-        "bestvideo[ext=mp4][vcodec^=avc1]+bestaudio[ext=m4a][acodec=aac]/bestvideo[ext=mp4][vcodec=h264]+bestaudio[ext=m4a]/best[ext=mp4]/best";
+        "bestvideo[ext=mp4][vcodec^=avc1]+bestaudio[ext=m4a]/bestvideo[ext=mp4][vcodec^=h264]+bestaudio[ext=m4a]/best[ext=mp4]/best";
 
       // If user specified a format, use it (but still apply MP4 container preference)
       if (userConfig.f || userConfig.format) {
@@ -412,6 +412,7 @@ export class YtDlpDownloader {
       }
 
       // Add YouTube specific flags if it's a YouTube URL
+      // Always apply preferred formats for YouTube to ensure codec compatibility (H.264/AAC for Safari)
       if (videoUrl.includes("youtube.com") || videoUrl.includes("youtu.be")) {
         flags.format = youtubeFormat;