Lessons System (Text, Video, Audio) for LMS

Developing Lessons System in LMS (Text, Video, Audio)

The lessons system is the core of LMS. Each lesson renders by type: video with player and subtitles, text with formatting and embedded media, audio with transcripts. Plus tracking — how much watched, when completed.

Lesson Types and Data

interface VideoLessonContent {
  videoUrl: string;        // HLS stream or direct mp4
  duration: number;        // seconds
  subtitles: Array<{ lang: string; label: string; url: string }>;
  chapters?: Array<{ title: string; time: number }>;
}

interface TextLessonContent {
  body: string;           // HTML or Markdown
  estimatedMinutes: number;
  attachments?: Array<{ name: string; url: string; size: number }>;
}

interface AudioLessonContent {
  audioUrl: string;
  duration: number;
  transcript?: string;    // text transcription
}

Video Player with View Tracking

import ReactPlayer from 'react-player';
import { useState, useRef, useCallback } from 'react';

function VideoLesson({ lesson, enrollmentId, onComplete }) {
  const playerRef = useRef<ReactPlayer>(null);
  const [played, setPlayed] = useState(0);
  const [completed, setCompleted] = useState(lesson.progress?.completed ?? false);

  const handleProgress = useCallback(async ({ played: p }) => {
    setPlayed(p);
    // Save every 10% progress
    if (Math.floor(p * 10) > Math.floor((p - 0.01) * 10)) {
      await saveProgress(enrollmentId, lesson.id, p);
    }
  }, []);

  const handleEnded = useCallback(async () => {
    if (!completed) {
      setCompleted(true);
      await fetch(`/api/enrollments/${enrollmentId}/lessons/${lesson.id}/complete`, {
        method: 'POST',
      });
      onComplete?.(lesson.id);
    }
  }, [completed]);

  // Auto-complete at 90%+ watched
  const handleProgress2 = useCallback(({ played: p }) => {
    handleProgress({ played: p });
    if (p >= 0.9 && !completed) {
      handleEnded();
    }
  }, [handleProgress, handleEnded, completed]);

  return (
    <div className="space-y-4">
      <div className="relative aspect-video bg-black rounded-xl overflow-hidden">
        <ReactPlayer
          ref={playerRef}
          url={lesson.content.videoUrl}
          width="100%"
          height="100%"
          controls
          onProgress={handleProgress2}
          onEnded={handleEnded}
          config={{
            file: {
              tracks: lesson.content.subtitles.map(s => ({
                kind: 'subtitles',
                src: s.url,
                srcLang: s.lang,
                label: s.label,
              })),
            },
          }}
        />
      </div>

      {lesson.content.chapters?.length > 0 && (
        <div>
          <h3 className="font-semibold text-gray-800 mb-2">Contents</h3>
          <ul className="space-y-1">
            {lesson.content.chapters.map((ch, i) => (
              <li key={i}>
                <button
                  onClick={() => playerRef.current?.seekTo(ch.time)}
                  className="text-sm text-blue-600 hover:underline"
                >
                  {formatTime(ch.time)} — {ch.title}
                </button>
              </li>
            ))}
          </ul>
        </div>
      )}

      {completed && (
        <div className="flex items-center gap-2 text-green-600 text-sm">
          <span>✓</span> Lesson completed
        </div>
      )}
    </div>
  );
}

Video Upload and Transcoding

Direct MP4 doesn't work well for large files and slow internet. Use HLS:

import ffmpeg from 'fluent-ffmpeg';

async function transcodeToHLS(inputPath: string, outputDir: string): Promise<string> {
  await fs.promises.mkdir(outputDir, { recursive: true });

  return new Promise((resolve, reject) => {
    ffmpeg(inputPath)
      .outputOptions([
        '-profile:v baseline',
        '-hls_time 6',      // 6 seconds per segment
        '-f hls',
      ])
      .output(path.join(outputDir, 'index.m3u8'))
      .on('end', () => resolve(`${outputDir}/index.m3u8`))
      .on('error', reject)
      .run();
  });
}

videoProcessingQueue.process(async (job) => {
  const { uploadedPath, lessonId } = job.data;
  const outputDir = `storage/lessons/${lessonId}/hls`;

  const hlsPath = await transcodeToHLS(uploadedPath, outputDir);
  const url = await uploadHLSToS3(outputDir, `lessons/${lessonId}`);

  await db.lessons.update(lessonId, {
    content: { videoUrl: url, status: 'ready' }
  });
});

Text Lesson with Editor

import { useEditor, EditorContent } from '@tiptap/react';
import StarterKit from '@tiptap/starter-kit';
import Image from '@tiptap/extension-image';

function TextLessonViewer({ content, onComplete }) {
  const editor = useEditor({
    content: content.body,
    editable: false,
    extensions: [StarterKit, Image],
  });

  const containerRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const handleScroll = () => {
      if (containerRef.current) {
        const rect = containerRef.current.getBoundingClientRect();
        const scrolled = window.innerHeight - rect.bottom > 0;
        if (scrolled) onComplete?.();
      }
    };

    window.addEventListener('scroll', handleScroll);
    return () => window.removeEventListener('scroll', handleScroll);
  }, [onComplete]);

  return <EditorContent editor={editor} ref={containerRef} />;
}

Timeframe

Video lesson with player and tracking — 3–5 days. Text/audio lessons with editor and transcoding — 5–7 days. Full lesson system — 2–3 weeks.