diff --git a/.gitignore b/.gitignore
index d6b7901..7647573 100644
--- a/.gitignore
+++ b/.gitignore
@@ -140,4 +140,7 @@ ayylmao.js
 
 # Local media files (served by python video_server.py)
 media/*
-!media/.gitkeep
\ No newline at end of file
+!media/.gitkeep
+
+# HLS cache (generated by video_server.py via ffmpeg)
+.hls_cache/
\ No newline at end of file
diff --git a/README.md b/README.md
index 341d83a..e90f967 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,17 @@ This repo also includes a small Python server that serves local video files with
 - Served as: `http://localhost:8001/media/<filename>`
 - List endpoint: `http://localhost:8001/api/media`
 
+### HLS (for better browser compatibility, especially MKV)
+The Python server can also **generate and serve HLS** (`.m3u8` + `.ts`) using `ffmpeg`, and the web player will automatically try this when a `/media/*.mkv` file is used (or when direct playback fails).
+
+- Prepare endpoint: `http://localhost:8001/api/hls?source=<path relative to media>`
+- Playlist served from: `http://localhost:8001/hls/<id>/index.m3u8`
+- Output is cached under: `./.hls_cache/` (ignored by git)
+
+Example:
+- Source: `http://localhost:8001/media/MyMovie.mkv`
+- The player will request: `http://localhost:8001/api/hls?source=MyMovie.mkv` and then play the returned `.m3u8`.
+
 ### Install
 
 ```bash
diff --git a/__pycache__/video_server.cpython-312.pyc b/__pycache__/video_server.cpython-312.pyc
index 95df0ed..d24902e 100644
Binary files a/__pycache__/video_server.cpython-312.pyc and b/__pycache__/video_server.cpython-312.pyc differ
diff --git a/public/js/app_player.js b/public/js/app_player.js
index 8c87c09..cd89673 100644
--- a/public/js/app_player.js
+++ b/public/js/app_player.js
@@ -90,6 +90,36 @@ function looksLikeVideoFile(url) {
   return /\.(mp4|mkv|webm|ogg|ogv|mov|m4v)(\?|#|$)/.test(s);
 }
 
+function isMkv(url) {
+  try {
+    const u = new URL(url, window.location.origin);
+    return u.pathname.toLowerCase().endsWith('.mkv');
+  } catch (_) {
+    return /\.mkv(\?|#|$)/i.test(String(url || ''));
+  }
+}
+
+async function tryGetGeneratedHlsPlaylist(rawUrl) {
+  // Only supports the python server's /media/<path> URLs.
+  try {
+    const u = new URL(rawUrl, window.location.origin);
+    if (!u.pathname.startsWith('/media/')) return null;
+    const rel = decodeURIComponent(u.pathname.slice('/media/'.length));
+    if (!rel) return null;
+
+    const api = new URL('/api/hls', u.origin);
+    api.searchParams.set('source', rel);
+    const res = await fetch(api.toString(), { method: 'GET' });
+    if (!res.ok) return null;
+    const data = await res.json().catch(() => null);
+    const playlist = data?.playlist_abs_url || data?.playlist_url;
+    if (!playlist) return null;
+    return playlist.startsWith('http') ? playlist : new URL(playlist, u.origin).toString();
+  } catch (_) {
+    return null;
+  }
+}
+
 function toYoutubeEmbed(url) {
   try {
     const u = new URL(url);
@@ -210,14 +240,31 @@ async function playVodLink(vodLink) {
 
   // Direct video file
   if (looksLikeVideoFile(raw)) {
+    // MKV is commonly not playable in browsers; try HLS generation first if it's from our python server.
+    if (isMkv(raw)) {
+      const playlist = await tryGetGeneratedHlsPlaylist(raw);
+      if (playlist) {
+        setSourceLabel('HLS (generated)');
+        return await playVodLink(playlist);
+      }
+    }
+
     setSourceLabel('Direct video file');
     const videoEl = showVideoPlayer();
     if (!videoEl) return;
     videoEl.src = raw;
     videoEl.addEventListener('error', () => {
-      // If the browser can't play it (or CORS blocks), fall back to iframe.
-      setSourceLabel('Embed (fallback)');
-      showEmbedPlayer(raw);
+      // If the browser can't play it (or CORS blocks), try HLS from the python server, then fall back to iframe.
+      (async () => {
+        const playlist = await tryGetGeneratedHlsPlaylist(raw);
+        if (playlist) {
+          setSourceLabel('HLS (generated)');
+          await playVodLink(playlist);
+          return;
+        }
+        setSourceLabel('Embed (fallback)');
+        showEmbedPlayer(raw);
+      })();
     }, { once: true });
     try { videoEl.load(); } catch (_) {}
     return;
diff --git a/video_server.py b/video_server.py
index 53b6aca..99bcaf0 100644
--- a/video_server.py
+++ b/video_server.py
@@ -1,16 +1,21 @@
 import mimetypes
 import os
 import re
+import shutil
+import subprocess
+import time
+import hashlib
 from pathlib import Path
 from typing import Generator, Iterable, Optional, Tuple
 
-from fastapi import FastAPI, HTTPException, Request, Response
+from fastapi import FastAPI, HTTPException, Query, Request, Response
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import JSONResponse, StreamingResponse
 
 APP_NAME = "video-file-server"
 BASE_DIR = Path(__file__).resolve().parent
 MEDIA_DIR = BASE_DIR / "media"
+HLS_CACHE_DIR = Path(os.getenv("HLS_CACHE_DIR", str(BASE_DIR / ".hls_cache"))).resolve()
 
 # Allow common video types (what browsers can play is separate from what we serve).
 ALLOWED_EXTS = {".mp4", ".mkv"}
@@ -104,6 +109,159 @@ def _iter_file(path: Path, start: int, end: int, chunk_size: int = 1024 * 1024)
             yield chunk
 
 
+def _hls_content_type(path: Path) -> str:
+    ext = path.suffix.lower()
+    if ext == ".m3u8":
+        return "application/vnd.apple.mpegurl"
+    if ext == ".ts":
+        return "video/mp2t"
+    ctype, _ = mimetypes.guess_type(str(path))
+    return ctype or "application/octet-stream"
+
+
+def _hls_id_for_media(path: Path) -> str:
+    rel = path.relative_to(MEDIA_DIR).as_posix()
+    st = path.stat()
+    key = f"{rel}|{st.st_size}|{st.st_mtime_ns}".encode("utf-8")
+    return hashlib.sha1(key).hexdigest()
+
+
+def _acquire_lock(lock_path: Path, timeout_s: int = 600) -> None:
+    """
+    Simple file lock to avoid concurrent transcodes for the same id.
+    """
+    started = time.time()
+    while True:
+        try:
+            fd = os.open(str(lock_path), os.O_CREAT | os.O_EXCL | os.O_WRONLY)
+            try:
+                os.write(fd, str(os.getpid()).encode("utf-8"))
+            finally:
+                os.close(fd)
+            return
+        except FileExistsError:
+            if time.time() - started > timeout_s:
+                raise HTTPException(status_code=409, detail="HLS generation already running")
+            time.sleep(0.25)
+
+
+def _release_lock(lock_path: Path) -> None:
+    try:
+        lock_path.unlink(missing_ok=True)
+    except Exception:
+        # Best-effort; lock will be overwritten on next run if needed.
+        pass
+
+
+def _ensure_hls_for_media(media_path: Path) -> str:
+    """
+    Generates an HLS VOD playlist for a given media file in HLS_CACHE_DIR.
+    Returns the HLS id.
+    """
+    hls_id = _hls_id_for_media(media_path)
+    out_dir = HLS_CACHE_DIR / hls_id
+    index_path = out_dir / "index.m3u8"
+    if index_path.exists():
+        return hls_id
+
+    HLS_CACHE_DIR.mkdir(parents=True, exist_ok=True)
+    lock_path = HLS_CACHE_DIR / f"{hls_id}.lock"
+    _acquire_lock(lock_path)
+    try:
+        # Another process might have finished while we waited.
+        if index_path.exists():
+            return hls_id
+
+        tmp_dir = HLS_CACHE_DIR / f"{hls_id}.tmp"
+        if tmp_dir.exists():
+            shutil.rmtree(tmp_dir, ignore_errors=True)
+        tmp_dir.mkdir(parents=True, exist_ok=True)
+
+        hls_time = os.getenv("HLS_TIME", "6").strip()
+        crf = os.getenv("HLS_CRF", "23").strip()
+        preset = os.getenv("HLS_PRESET", "veryfast").strip()
+        audio_bitrate = os.getenv("HLS_AUDIO_BITRATE", "160k").strip()
+
+        cmd = [
+            "ffmpeg",
+            "-hide_banner",
+            "-loglevel",
+            "error",
+            "-y",
+            "-i",
+            str(media_path),
+            "-map",
+            "0:v:0",
+            "-map",
+            "0:a?",
+            "-c:v",
+            "libx264",
+            "-preset",
+            preset,
+            "-crf",
+            crf,
+            "-c:a",
+            "aac",
+            "-b:a",
+            audio_bitrate,
+            "-f",
+            "hls",
+            "-hls_time",
+            hls_time,
+            "-hls_playlist_type",
+            "vod",
+            "-hls_flags",
+            "independent_segments",
+            "-hls_segment_filename",
+            str(tmp_dir / "seg_%05d.ts"),
+            str(tmp_dir / "index.m3u8"),
+        ]
+
+        try:
+            subprocess.run(cmd, check=True, capture_output=True)
+        except FileNotFoundError as exc:
+            raise HTTPException(status_code=500, detail="ffmpeg not installed") from exc
+        except subprocess.CalledProcessError as exc:
+            stderr = (exc.stderr or b"").decode("utf-8", errors="replace").strip()
+            raise HTTPException(status_code=500, detail=f"HLS generation failed: {stderr or 'ffmpeg error'}") from exc
+
+        # Move into place.
+        if out_dir.exists():
+            # Race: someone else created it; keep theirs.
+            shutil.rmtree(tmp_dir, ignore_errors=True)
+            return hls_id
+
+        os.replace(str(tmp_dir), str(out_dir))
+        return hls_id
+    finally:
+        _release_lock(lock_path)
+
+
+def _safe_resolve_hls_asset(hls_id: str, asset_path: str) -> Path:
+    if not re.fullmatch(r"[a-f0-9]{40}", hls_id):
+        raise HTTPException(status_code=400, detail="Invalid HLS id")
+
+    asset_path = asset_path.replace("\\", "/").lstrip("/")
+    if not asset_path:
+        raise HTTPException(status_code=404, detail="Missing asset path")
+
+    root = (HLS_CACHE_DIR / hls_id).resolve()
+    candidate = (root / asset_path).resolve()
+    try:
+        candidate.relative_to(root)
+    except ValueError as exc:
+        raise HTTPException(status_code=400, detail="Invalid asset path") from exc
+
+    if not candidate.is_file():
+        raise HTTPException(status_code=404, detail="Asset not found")
+
+    # Restrict to typical HLS outputs.
+    if candidate.suffix.lower() not in {".m3u8", ".ts"}:
+        raise HTTPException(status_code=415, detail="Unsupported asset type")
+
+    return candidate
+
+
 app = FastAPI(title=APP_NAME)
 
 # Default to permissive CORS because the player may be on another port/host.
@@ -148,6 +306,49 @@ def list_media() -> JSONResponse:
     return JSONResponse({"items": items})
 
 
+@app.get("/api/hls")
+def prepare_hls(request: Request, source: str = Query(..., description="Path relative to ./media (e.g. MyMovie.mkv)")) -> JSONResponse:
+    """
+    Generates (and caches) an HLS VOD playlist for a local media file.
+
+    Returns an id and a playlist URL like: /hls/<id>/index.m3u8
+    """
+    media_path = _safe_resolve_media_path(source)
+    hls_id = _ensure_hls_for_media(media_path)
+    base = str(request.base_url).rstrip("/")
+    playlist_path = f"/hls/{hls_id}/index.m3u8"
+    return JSONResponse(
+        {
+            "hls_id": hls_id,
+            "playlist_url": playlist_path,
+            "playlist_abs_url": f"{base}{playlist_path}",
+        }
+    )
+
+
+@app.api_route("/hls/{hls_id}/{asset_path:path}", methods=["GET", "HEAD"])
+async def serve_hls_asset(hls_id: str, asset_path: str, request: Request) -> Response:
+    path = _safe_resolve_hls_asset(hls_id, asset_path)
+    size = path.stat().st_size
+    ctype = _hls_content_type(path)
+
+    headers = {
+        "Content-Type": ctype,
+        "Content-Length": str(size),
+        "Cache-Control": "no-store",
+    }
+
+    if request.method == "HEAD":
+        return Response(status_code=200, headers=headers)
+
+    return StreamingResponse(
+        _iter_file(path, 0, size - 1),
+        status_code=200,
+        headers=headers,
+        media_type=ctype,
+    )
+
+
 @app.api_route("/media/{file_path:path}", methods=["GET", "HEAD"])
 async def serve_media(file_path: str, request: Request) -> Response:
     path = _safe_resolve_media_path(file_path)