video_socket-server/test/recording-composer.test.ts

import { buildFfmpegCompositionArgs } from '../src/recording/composer';
import { ServerTrackRecordingFile } from '../src/recording/storage';

function file(
  filename: string,
  trackKind: string,
  participantId: string,
  role = 'participant',
  recordingStartedAt = '2026-06-01T00:00:00.000Z',
  recordingEndedAt = '2026-06-01T00:00:10.000Z'
): ServerTrackRecordingFile {
  return {
    meetingId: 'room-1',
    directory: 'recordings/room-1',
    filename,
    filePath: `recordings/room-1/${filename}`,
    metadataPath: `recordings/room-1/${filename}.json`,
    recordingId: 'recording-1',
    participantId,
    trackId: `${participantId}-${trackKind}`,
    trackKind,
    uploadedAt: recordingStartedAt,
    recordingStartedAt,
    recordingEndedAt,
    metadata: { role, recordingStartedAt, recordingEndedAt, updatedAt: recordingEndedAt }
  };
}

describe('recording composer', () => {
  test('builds ffmpeg args for host-led video layout and mixed audio', () => {
    const args = buildFfmpegCompositionArgs({
      videoInputs: [
        file('p1-video.webm', 'video', 'p1', 'host'),
        file('p2-video.webm', 'video', 'p2')
      ],
      audioInputs: [
        file('p1-audio.webm', 'audio', 'p1'),
        file('p2-audio.webm', 'audio', 'p2')
      ],
      outputPath: 'recordings/room-1/output.webm',
      format: 'webm'
    });

    expect(args).toContain('-filter_complex');
    expect(args.join(' ')).toContain('xstack=inputs=2');
    expect(args.join(' ')).toContain('scale=1280:540');
    expect(args.join(' ')).toContain('scale=1280:180');
    expect(args.join(' ')).toContain('layout=0_0|0_540');
    expect(args.join(' ')).toContain('amix=inputs=2');
    expect(args).toContain('libvpx-vp9');
    expect(args).toContain('libopus');
    expect(args).not.toContain('-shortest');
    expect(args[args.length - 1]).toBe('recordings/room-1/output.webm');
  });

  test('places host in the first row even when host input is not first', () => {
    const args = buildFfmpegCompositionArgs({
      videoInputs: [
        file('p1-video.webm', 'video', 'p1'),
        file('host-video.webm', 'video', 'host', 'host'),
        file('p2-video.webm', 'video', 'p2')
      ],
      audioInputs: [],
      outputPath: 'recordings/room-1/output.webm',
      format: 'webm'
    });

    const filter = args[args.indexOf('-filter_complex') + 1];
    expect(args.slice(0, 7)).toEqual([
      '-y',
      '-i',
      'recordings/room-1/host-video.webm',
      '-i',
      'recordings/room-1/p1-video.webm',
      '-i',
      'recordings/room-1/p2-video.webm'
    ]);
    expect(filter).toContain('scale=1280:540');
    expect(filter).toContain('scale=640:180');
    expect(filter).toContain('layout=0_0|0_540|640_540');
  });

  test('builds mp4 encoder args', () => {
    const args = buildFfmpegCompositionArgs({
      videoInputs: [file('p1-video.webm', 'video', 'p1')],
      audioInputs: [],
      outputPath: 'recordings/room-1/output.mp4',
      format: 'mp4'
    });

    expect(args).toContain('libx264');
    expect(args).toContain('-pix_fmt');
    expect(args).not.toContain('libopus');
  });

  test('pads late participant tracks to keep the room timeline aligned', () => {
    const args = buildFfmpegCompositionArgs({
      videoInputs: [
        file('host-video.webm', 'video', 'host', 'host', '2026-06-01T00:00:00.000Z', '2026-06-01T00:00:10.000Z'),
        file('p1-video.webm', 'video', 'p1', 'participant', '2026-06-01T00:00:02.500Z', '2026-06-01T00:00:10.000Z')
      ],
      audioInputs: [
        file('host-audio.webm', 'audio', 'host', 'host', '2026-06-01T00:00:00.000Z', '2026-06-01T00:00:10.000Z'),
        file('p1-audio.webm', 'audio', 'p1', 'participant', '2026-06-01T00:00:02.500Z', '2026-06-01T00:00:10.000Z')
      ],
      outputPath: 'recordings/room-1/output.webm',
      format: 'webm'
    });

    const filter = args[args.indexOf('-filter_complex') + 1];
    expect(filter).toContain('[0:v]split=2[vin0_0][vin0_1]');
    expect(filter).toContain('[vin0_0]trim=start=0:duration=2.5');
    expect(filter).toContain('[vin0_1]trim=start=2.5:duration=7.5');
    expect(filter).toContain('[1:v]trim=start=0:duration=7.5');
    expect(filter).toContain('concat=n=2:v=1:a=0[vout]');
    expect(filter).toContain('[2:a]aresample=async=1:first_pts=0[a0]');
    expect(filter).toContain('[3:a]aresample=async=1:first_pts=0,adelay=2500:all=1[a1]');
    expect(filter).toContain('[a0][a1]amix=inputs=2:duration=longest');
  });

  test('changes the layout when participants join and leave without overlapping', () => {
    const args = buildFfmpegCompositionArgs({
      videoInputs: [
        file('host-video.webm', 'video', 'host', 'host', '2026-06-01T00:00:00.000Z', '2026-06-01T00:00:12.000Z'),
        file('p1-video.webm', 'video', 'p1', 'participant', '2026-06-01T00:00:00.000Z', '2026-06-01T00:00:05.000Z'),
        file('p2-video.webm', 'video', 'p2', 'participant', '2026-06-01T00:00:05.000Z', '2026-06-01T00:00:12.000Z')
      ],
      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('layout=0_0|0_540');
    expect(filter).toContain('[0:v]split=2[vin0_0][vin0_1]');
    expect(filter).toContain('[vin0_0]trim=start=0:duration=5');
    expect(filter).toContain('[1:v]trim=start=0:duration=5');
    expect(filter).toContain('[vin0_1]trim=start=5:duration=7');
    expect(filter).toContain('[2:v]trim=start=0:duration=7');
    expect(filter).toContain('concat=n=2:v=1:a=0[vout]');
    expect(filter).not.toContain('xstack=inputs=3');
  });

  test('keeps separate viewports for participants whose video intervals overlap', () => {
    const args = buildFfmpegCompositionArgs({
      videoInputs: [
        file('host-video.webm', 'video', 'host', 'host', '2026-06-01T00:00:00.000Z', '2026-06-01T00:00:12.000Z'),
        file('p1-video.webm', 'video', 'p1', 'participant', '2026-06-01T00:00:00.000Z', '2026-06-01T00:00:08.000Z'),
        file('p2-video.webm', 'video', 'p2', 'participant', '2026-06-01T00:00:05.000Z', '2026-06-01T00:00:12.000Z')
      ],
      audioInputs: [],
      outputPath: 'recordings/room-1/output.webm',
      format: 'webm'
    });

    const filter = args[args.indexOf('-filter_complex') + 1];
    expect(filter).toContain('xstack=inputs=3');
    expect(filter).toContain('layout=0_0|0_540|640_540');
  });
});