Unity启动，录制视频没有文件产出

test/recording-composer.test.ts

@@ -93,6 +93,24 @@ describe('recording composer', () => {
     expect(args).not.toContain('libopus');
   });
 
+  test('falls back to one video segment when input end timestamps are missing', () => {
+    const args = buildFfmpegCompositionArgs({
+      videoInputs: [
+        file('host-video.webm', 'video', 'host', 'host', '2026-06-01T00:00:00.000Z', ''),
+        file('p1-video.webm', 'video', 'p1', 'participant', '2026-06-01T00:00:02.500Z', '')
+      ],
+      audioInputs: [],
+      outputPath: 'recordings/room-1/output.webm',
+      format: 'webm'
+    });
+
+    const filter = args[args.indexOf('-filter_complex') + 1];
+    expect(filter).toContain('xstack=inputs=2');
+    expect(filter).toContain('trim=start=0,setpts=PTS-STARTPTS');
+    expect(filter).not.toContain('concat=n=0');
+    expect(args).not.toContain('-t');
+  });
+
   test('pads late participant tracks to keep the room timeline aligned', () => {
     const args = buildFfmpegCompositionArgs({
       videoInputs: [