Initial commit — yt-dlf YouTube downloader & transcript extractor

SvelteKit web frontend for yt-dlp and ffmpeg. Paste a YouTube URL to
download best-quality video, subtitles (original + EN + DE), and thumbnail.
Subtitles are converted to clean Markdown. Optional audio extraction to MP3.

Supports ZIP & Send mode: downloaded files are packed into a ZIP and
delivered to the browser, with optional server-side cleanup after delivery.
An extra directory (ZIP_EXTRA_DIR) can be bundled into every ZIP.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

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+node_modules
+
+# Output
+.output
+.vercel
+.netlify
+.wrangler
+/.svelte-kit
+/build
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Claude Code
+.claude/
+
+# Env
+.env
+.env.*
+!.env.example
+!.env.test
+
+# Vite
+vite.config.js.timestamp-*
+vite.config.ts.timestamp-*

.npmrc

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+engine-strict=true

.vscode/extensions.json

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+{
+	"recommendations": ["svelte.svelte-vscode"]
+}

INSTALL.md

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+# Deployment
+
+## What's in the package
+
+```
+build/                    ← compiled SvelteKit server (self-contained, no npm needed)
+scripts/
+  subtitle_to_markdown.py ← standalone subtitle converter CLI
+  create_zip.py           ← ZIP creation helper (used internally by the server)
+start.sh                  ← startup script
+README.md
+INSTALL.md
+```
+
+## Prerequisites on the Linux server
+
+Node.js 18 or newer, Python 3, yt-dlp, and ffmpeg must be installed.
+
+```bash
+# ffmpeg, Node.js, and Python via apt
+sudo apt install ffmpeg nodejs python3
+
+# yt-dlp (latest release)
+sudo curl -L https://github.com/yt-dlp/yt-dlp/releases/latest/download/yt-dlp \
+  -o /usr/local/bin/yt-dlp
+sudo chmod +x /usr/local/bin/yt-dlp
+```
+
+## Installation
+
+```bash
+tar -xzf yt-dlf.tar.gz
+cd yt-dlf
+```
+
+## Running
+
+```bash
+./start.sh
+```
+
+The server listens on port 3000 by default. Open `http://your-server:3000` in a browser.
+
+## Environment variables
+
+Edit `start.sh` to configure the variables below, or pass them directly on the command line.
+
+### General
+
+| Variable | Default | Purpose |
+|---|---|---|
+| `PORT` | `3000` | Port to listen on |
+| `ORIGIN` | `http://localhost:PORT` | Public URL of the server — set this in production |
+| `YTDLP_PATH` | `yt-dlp` | Full path to yt-dlp binary if not on PATH |
+| `FFMPEG_PATH` | `ffmpeg` | Full path to ffmpeg binary if not on PATH |
+| `DOWNLOAD_DIR` | `~/YouTube` | Directory where downloaded files are stored on the server |
+
+### ZIP & Send mode
+
+When `ZIP_AND_SEND=true`, all downloaded files are packed into a ZIP and offered as a browser download instead of (only) being saved on the server. A random prefix is added to the temporary directory name to avoid collisions when multiple users download the same video simultaneously.
+
+| Variable | Default | Purpose |
+|---|---|---|
+| `ZIP_AND_SEND` | `false` | Enable ZIP & Send mode |
+| `ZIP_EXTRA_DIR` | _(none)_ | Optional directory whose files are added to every ZIP alongside the downloaded files. Subdirectory structure is preserved. |
+| `DELETE_AFTER_SEND` | `false` | Delete files from the server after the ZIP has been sent to the browser |
+| `DELETE_DELAY` | `0` | Seconds to wait before deleting files after the ZIP has been sent |
+
+### Examples
+
+Custom port and public URL:
+
+```bash
+PORT=8080 ORIGIN=http://myserver:8080 ./start.sh
+```
+
+ZIP & Send with cleanup after 60 seconds:
+
+```bash
+ZIP_AND_SEND=true DELETE_AFTER_SEND=true DELETE_DELAY=60 ./start.sh
+```
+
+ZIP & Send with extra files bundled into every download:
+
+```bash
+ZIP_AND_SEND=true ZIP_EXTRA_DIR=/opt/yt-dlf/extras ./start.sh
+```

README.md

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+# yt-dlf
+
+YouTube Downloader & Transcript Extractor — a local web frontend for `yt-dlp` and `ffmpeg`.
+
+## Features
+
+- Paste a YouTube URL and download the best available video quality
+- Subtitles downloaded automatically in the video's original language, English, and German (where available)
+- Subtitles converted to clean Markdown (timestamps stripped, text deduplicated and paragraph-wrapped)
+- Optional audio extraction to MP3 via ffmpeg
+- Real-time progress log streamed to the browser
+- Files saved to `~/YouTube/<video title>/`
+
+## Prerequisites
+
+```bash
+brew install yt-dlp ffmpeg
+```
+
+Node.js 16+ is required for the web app (tested with Node 26).
+
+## Project Layout
+
+```
+yt-dlf/
+├── scripts/
+│   └── subtitle_to_markdown.py   # standalone CLI converter
+├── src/
+│   ├── lib/
+│   │   └── subtitle.js           # JS conversion module (used by web app)
+│   └── routes/
+│       ├── api/download/
+│       │   └── +server.js        # SSE endpoint — runs yt-dlp / ffmpeg
+│       ├── +layout.svelte
+│       └── +page.svelte          # UI
+└── vite.config.js
+```
+
+## Running the web app
+
+```bash
+npm install       # first time only
+npm run dev       # starts on http://localhost:5173
+```
+
+To use a custom port:
+
+```bash
+PORT=8080 npm run dev
+```
+
+## Standalone subtitle converter
+
+Convert a `.vtt` or `.srt` subtitle file to Markdown directly from the terminal:
+
+```bash
+./scripts/subtitle_to_markdown.py video.en.vtt
+./scripts/subtitle_to_markdown.py video.en.vtt output.md
+```
+
+Output is saved next to the input file (same name, `.md` extension) unless a second argument is given.

jsconfig.json

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+{
+	"extends": "./.svelte-kit/tsconfig.json",
+	"compilerOptions": {
+		"allowJs": true,
+		"checkJs": false,
+		"moduleResolution": "bundler"
+	}
+	// Path aliases are handled by https://svelte.dev/docs/kit/configuration#alias
+	// except $lib which is handled by https://svelte.dev/docs/kit/configuration#files
+	//
+	// If you want to overwrite includes/excludes, make sure to copy over the relevant includes/excludes
+	// from the referenced tsconfig.json - TypeScript does not merge them in
+}

package.json

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+{
+	"name": "yt-dlf",
+	"private": true,
+	"version": "0.0.1",
+	"type": "module",
+	"scripts": {
+		"dev": "vite dev",
+		"build": "vite build",
+		"preview": "vite preview",
+		"prepare": "svelte-kit sync || echo ''"
+	},
+	"devDependencies": {
+		"@sveltejs/adapter-auto": "^7.0.1",
+		"@sveltejs/adapter-node": "^5.5.4",
+		"@sveltejs/kit": "^2.57.0",
+		"@sveltejs/vite-plugin-svelte": "^7.0.0",
+		"svelte": "^5.55.2",
+		"vite": "^8.0.7"
+	},
+	"dependencies": {
+		"archiver": "^8.0.0"
+	}
+}

scripts/create_zip.py

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+#!/usr/bin/env python3
+"""Create a ZIP archive from a directory, with an optional extra directory.
+
+Usage: create_zip.py <source_dir> <output.zip> <archive_dir_name> [extra_dir]
+
+Files from source_dir and (if given) extra_dir are both stored under
+archive_dir_name/ in the ZIP, regardless of the actual directory names on disk.
+"""
+import sys
+import zipfile
+from pathlib import Path
+
+if len(sys.argv) < 4:
+    print(f'Usage: {sys.argv[0]} <source_dir> <output.zip> <archive_dir_name> [extra_dir]', file=sys.stderr)
+    sys.exit(1)
+
+source_dir = Path(sys.argv[1])
+zip_path = sys.argv[2]
+archive_name = sys.argv[3]
+extra_dir = Path(sys.argv[4]) if len(sys.argv) >= 5 else None
+
+with zipfile.ZipFile(zip_path, 'w', zipfile.ZIP_DEFLATED, compresslevel=6) as zf:
+    for file_path in sorted(source_dir.rglob('*')):
+        if file_path.is_file():
+            arcname = Path(archive_name) / file_path.relative_to(source_dir)
+            zf.write(file_path, arcname)
+
+    if extra_dir and extra_dir.is_dir():
+        for file_path in sorted(extra_dir.rglob('*')):
+            if file_path.is_file():
+                arcname = Path(archive_name) / file_path.relative_to(extra_dir)
+                zf.write(file_path, arcname)
+
+print(f'Created: {zip_path}')

scripts/subtitle_to_markdown.py

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+#!/usr/bin/env python3
+"""Convert VTT or SRT subtitle files to Markdown plain text."""
+import re
+import sys
+from pathlib import Path
+
+
+def strip_html(text):
+    return re.sub(r'<[^>]+>', '', text)
+
+
+def parse_vtt(content):
+    blocks = re.split(r'\n{2,}', content.strip())
+    cues = []
+    for block in blocks:
+        lines = block.strip().splitlines()
+        if not lines:
+            continue
+        if lines[0].startswith('WEBVTT'):
+            continue
+        if lines[0].startswith('NOTE') or lines[0].startswith('STYLE'):
+            continue
+        ts_idx = next((i for i, l in enumerate(lines) if '-->' in l), None)
+        if ts_idx is None:
+            continue
+        text = ' '.join(
+            strip_html(l).strip()
+            for l in lines[ts_idx + 1:]
+            if strip_html(l).strip()
+        )
+        if text:
+            cues.append(text)
+    return cues
+
+
+def parse_srt(content):
+    blocks = re.split(r'\n{2,}', content.strip())
+    cues = []
+    for block in blocks:
+        lines = block.strip().splitlines()
+        text_lines = []
+        for line in lines:
+            line = line.strip()
+            if re.match(r'^\d+$', line):
+                continue
+            if re.match(r'\d{2}:\d{2}:\d{2}[,\.]\d{3}\s*-->', line):
+                continue
+            cleaned = strip_html(line)
+            if cleaned:
+                text_lines.append(cleaned)
+        if text_lines:
+            cues.append(' '.join(text_lines))
+    return cues
+
+
+def deduplicate(cues):
+    result = []
+    prev = None
+    for cue in cues:
+        if cue != prev:
+            result.append(cue)
+            prev = cue
+    return result
+
+
+def to_markdown(cues):
+    cues = deduplicate(cues)
+    if not cues:
+        return ''
+    full = ' '.join(cues)
+    sentences = re.split(r'(?<=[.!?…])\s+', full)
+    paragraphs = []
+    for i in range(0, len(sentences), 8):
+        paragraphs.append(' '.join(sentences[i:i + 8]))
+    return '\n\n'.join(paragraphs)
+
+
+def convert(input_path):
+    content = input_path.read_text(encoding='utf-8', errors='replace')
+    suffix = input_path.suffix.lower()
+    if suffix == '.vtt':
+        cues = parse_vtt(content)
+    elif suffix == '.srt':
+        cues = parse_srt(content)
+    else:
+        raise ValueError(f'Unsupported format: {suffix}')
+    return to_markdown(cues)
+
+
+if __name__ == '__main__':
+    if len(sys.argv) < 2:
+        print(f'Usage: {sys.argv[0]} <file.vtt|file.srt> [output.md]', file=sys.stderr)
+        sys.exit(1)
+
+    input_path = Path(sys.argv[1])
+    if not input_path.exists():
+        print(f'File not found: {input_path}', file=sys.stderr)
+        sys.exit(1)
+
+    md = convert(input_path)
+
+    output_path = Path(sys.argv[2]) if len(sys.argv) >= 3 else input_path.with_suffix('.md')
+    output_path.write_text(md, encoding='utf-8')
+    print(f'Saved: {output_path}')

src/app.html

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+<!doctype html>
+<html lang="en">
+	<head>
+		<meta charset="utf-8" />
+		<meta name="viewport" content="width=device-width, initial-scale=1" />
+		<meta name="text-scale" content="scale" />
+		%sveltekit.head%
+	</head>
+	<body data-sveltekit-preload-data="hover">
+		<div style="display: contents">%sveltekit.body%</div>
+	</body>
+</html>

src/lib/assets/favicon.svg

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+<svg xmlns="http://www.w3.org/2000/svg" width="107" height="128" viewBox="0 0 107 128"><title>svelte-logo</title><path d="M94.157 22.819c-10.4-14.885-30.94-19.297-45.792-9.835L22.282 29.608A29.92 29.92 0 0 0 8.764 49.65a31.5 31.5 0 0 0 3.108 20.231 30 30 0 0 0-4.477 11.183 31.9 31.9 0 0 0 5.448 24.116c10.402 14.887 30.942 19.297 45.791 9.835l26.083-16.624A29.92 29.92 0 0 0 98.235 78.35a31.53 31.53 0 0 0-3.105-20.232 30 30 0 0 0 4.474-11.182 31.88 31.88 0 0 0-5.447-24.116" style="fill:#ff3e00"/><path d="M45.817 106.582a20.72 20.72 0 0 1-22.237-8.243 19.17 19.17 0 0 1-3.277-14.503 18 18 0 0 1 .624-2.435l.49-1.498 1.337.981a33.6 33.6 0 0 0 10.203 5.098l.97.294-.09.968a5.85 5.85 0 0 0 1.052 3.878 6.24 6.24 0 0 0 6.695 2.485 5.8 5.8 0 0 0 1.603-.704L69.27 76.28a5.43 5.43 0 0 0 2.45-3.631 5.8 5.8 0 0 0-.987-4.371 6.24 6.24 0 0 0-6.698-2.487 5.7 5.7 0 0 0-1.6.704l-9.953 6.345a19 19 0 0 1-5.296 2.326 20.72 20.72 0 0 1-22.237-8.243 19.17 19.17 0 0 1-3.277-14.502 17.99 17.99 0 0 1 8.13-12.052l26.081-16.623a19 19 0 0 1 5.3-2.329 20.72 20.72 0 0 1 22.237 8.243 19.17 19.17 0 0 1 3.277 14.503 18 18 0 0 1-.624 2.435l-.49 1.498-1.337-.98a33.6 33.6 0 0 0-10.203-5.1l-.97-.294.09-.968a5.86 5.86 0 0 0-1.052-3.878 6.24 6.24 0 0 0-6.696-2.485 5.8 5.8 0 0 0-1.602.704L37.73 51.72a5.42 5.42 0 0 0-2.449 3.63 5.79 5.79 0 0 0 .986 4.372 6.24 6.24 0 0 0 6.698 2.486 5.8 5.8 0 0 0 1.602-.704l9.952-6.342a19 19 0 0 1 5.295-2.328 20.72 20.72 0 0 1 22.237 8.242 19.17 19.17 0 0 1 3.277 14.503 18 18 0 0 1-8.13 12.053l-26.081 16.622a19 19 0 0 1-5.3 2.328" style="fill:#fff"/></svg>

src/lib/index.js

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+// place files you want to import through the `$lib` alias in this folder.

src/lib/server/store.js

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+import { homedir } from 'os';
+import { join } from 'path';
+
+export const config = {
+	downloadDir: process.env.DOWNLOAD_DIR ?? join(homedir(), 'YouTube'),
+	zipAndSend: process.env.ZIP_AND_SEND === 'true',
+	zipExtraDir: process.env.ZIP_EXTRA_DIR ?? '',
+	deleteAfterSend: process.env.DELETE_AFTER_SEND === 'true',
+	deleteDelay: parseInt(process.env.DELETE_DELAY ?? '0') * 1000,
+};
+
+// token → { zipPath, outputDir, filename }
+export const zipStore = new Map();

src/lib/subtitle.js

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+import { readFileSync } from 'fs';
+import { extname } from 'path';
+
+function stripHtml(text) {
+	return text.replace(/<[^>]+>/g, '');
+}
+
+function parseVtt(content) {
+	const blocks = content.split(/\n{2,}/);
+	const cues = [];
+	for (const block of blocks) {
+		const lines = block.trim().split('\n');
+		if (!lines.length) continue;
+		if (lines[0].startsWith('WEBVTT')) continue;
+		if (lines[0].startsWith('NOTE') || lines[0].startsWith('STYLE')) continue;
+		const tsIdx = lines.findIndex(l => l.includes('-->'));
+		if (tsIdx === -1) continue;
+		const text = lines
+			.slice(tsIdx + 1)
+			.map(l => stripHtml(l).trim())
+			.filter(Boolean)
+			.join(' ');
+		if (text) cues.push(text);
+	}
+	return cues;
+}
+
+function parseSrt(content) {
+	const blocks = content.split(/\n{2,}/);
+	const cues = [];
+	for (const block of blocks) {
+		const lines = block.trim().split('\n');
+		const textLines = lines
+			.filter(l => !/^\d+$/.test(l.trim()))
+			.filter(l => !/\d{2}:\d{2}:\d{2}[,.]\d{3}\s*-->/.test(l))
+			.map(l => stripHtml(l).trim())
+			.filter(Boolean);
+		if (textLines.length) cues.push(textLines.join(' '));
+	}
+	return cues;
+}
+
+function deduplicate(cues) {
+	return cues.filter((c, i) => c !== cues[i - 1]);
+}
+
+function toMarkdown(cues) {
+	const deduped = deduplicate(cues);
+	if (!deduped.length) return '';
+	const full = deduped.join(' ');
+	const sentences = full.split(/(?<=[.!?…])\s+/);
+	const paragraphs = [];
+	for (let i = 0; i < sentences.length; i += 8) {
+		paragraphs.push(sentences.slice(i, i + 8).join(' '));
+	}
+	return paragraphs.join('\n\n');
+}
+
+export function convertSubtitleToMarkdown(filePath) {
+	const content = readFileSync(filePath, 'utf-8');
+	const ext = extname(filePath).toLowerCase();
+	if (ext === '.vtt') return toMarkdown(parseVtt(content));
+	if (ext === '.srt') return toMarkdown(parseSrt(content));
+	throw new Error(`Unsupported subtitle format: ${ext}`);
+}

src/routes/+layout.svelte

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+<script>
+	import favicon from '$lib/assets/favicon.svg';
+
+	let { children } = $props();
+</script>
+
+<svelte:head>
+	<link rel="icon" href={favicon} />
+</svelte:head>
+
+{@render children()}

src/routes/+page.svelte

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+<script>
+	let url = $state('');
+	let audioOnly = $state(false);
+	let downloading = $state(false);
+	let log = $state([]);
+	let status = $state('idle');
+	let logEl = $state(null);
+	let zipToken = $state(null);
+	let zipFilename = $state('');
+
+	function scrollToBottom() {
+		if (logEl) logEl.scrollTop = logEl.scrollHeight;
+	}
+
+	function startDownload() {
+		if (!url.trim() || downloading) return;
+		downloading = true;
+		log = [];
+		status = 'running';
+		zipToken = null;
+
+		const params = new URLSearchParams({ url: url.trim(), audio: String(audioOnly) });
+		const es = new EventSource(`/api/download?${params}`);
+
+		es.onmessage = (event) => {
+			const data = JSON.parse(event.data);
+			if (data.type !== 'zip-ready') log = [...log, data];
+			setTimeout(scrollToBottom, 0);
+
+			if (data.type === 'zip-ready') {
+				zipToken = data.token;
+				zipFilename = data.filename;
+			} else if (data.type === 'done') {
+				status = 'done';
+				es.close();
+				downloading = false;
+			} else if (data.type === 'error') {
+				status = 'error';
+				es.close();
+				downloading = false;
+			}
+		};
+
+		es.onerror = () => {
+			if (status === 'running') {
+				log = [...log, { type: 'error', message: 'Connection lost' }];
+				status = 'error';
+				downloading = false;
+			}
+			es.close();
+		};
+	}
+
+	function handleKeydown(e) {
+		if (e.key === 'Enter') startDownload();
+	}
+
+	function clearZip() {
+		zipToken = null;
+	}
+</script>
+
+<main>
+	<header>
+		<h1>yt-dlf</h1>
+		<p>YouTube Downloader &amp; Transcript Extractor</p>
+	</header>
+
+	<section class="controls">
+		<input
+			type="url"
+			bind:value={url}
+			placeholder="https://www.youtube.com/watch?v=…"
+			disabled={downloading}
+			onkeydown={handleKeydown}
+		/>
+
+		<div class="options">
+			<label>
+				<input type="checkbox" bind:checked={audioOnly} disabled={downloading} />
+				Extract audio (MP3)
+			</label>
+		</div>
+
+		<button onclick={startDownload} disabled={downloading || !url.trim()}>
+			{downloading ? 'Downloading…' : 'Download'}
+		</button>
+	</section>
+
+	{#if zipToken}
+		<section class="zip-section">
+			<a
+				class="zip-btn"
+				href="/api/zip?token={zipToken}"
+				download={zipFilename}
+				onclick={clearZip}
+			>
+				Download ZIP
+			</a>
+			<span class="zip-name">{zipFilename}</span>
+		</section>
+	{/if}
+
+	{#if log.length > 0}
+		<section class="log-section">
+			<div class="log-header">
+				<span
+					class="status-dot"
+					class:running={status === 'running'}
+					class:done={status === 'done'}
+					class:error={status === 'error'}
+				></span>
+				<span class="status-label">
+					{#if status === 'running'}Downloading…{:else if status === 'done'}Done{:else if status === 'error'}Error{/if}
+				</span>
+			</div>
+			<div class="log" bind:this={logEl}>
+				{#each log as entry}
+					<div class="line {entry.type}">{entry.message}</div>
+				{/each}
+			</div>
+		</section>
+	{/if}
+</main>
+
+<style>
+	:global(*, *::before, *::after) {
+		box-sizing: border-box;
+	}
+
+	:global(body) {
+		margin: 0;
+		background: #f5f5f0;
+		color: #1a1a1a;
+		font-family: system-ui, -apple-system, sans-serif;
+		min-height: 100vh;
+	}
+
+	main {
+		max-width: 800px;
+		margin: 0 auto;
+		padding: 3rem 1.5rem;
+	}
+
+	header {
+		text-align: center;
+		margin-bottom: 2.5rem;
+	}
+
+	h1 {
+		font-size: 2.25rem;
+		font-weight: 800;
+		color: #1a1a1a;
+		margin: 0;
+		letter-spacing: -0.03em;
+	}
+
+	header p {
+		color: #888;
+		margin: 0.35rem 0 0;
+		font-size: 0.95rem;
+	}
+
+	.controls {
+		display: flex;
+		flex-direction: column;
+		gap: 0.75rem;
+	}
+
+	input[type='url'] {
+		width: 100%;
+		padding: 0.8rem 1rem;
+		background: #fff;
+		border: 1px solid #d0d0c8;
+		border-radius: 8px;
+		color: #1a1a1a;
+		font-size: 1rem;
+		outline: none;
+		transition: border-color 0.15s;
+	}
+
+	input[type='url']:focus {
+		border-color: #65d000;
+	}
+
+	input[type='url']:disabled {
+		opacity: 0.45;
+	}
+
+	.options {
+		display: flex;
+		gap: 1.5rem;
+	}
+
+	label {
+		display: flex;
+		align-items: center;
+		gap: 0.45rem;
+		cursor: pointer;
+		color: #555;
+		font-size: 0.9rem;
+		user-select: none;
+	}
+
+	input[type='checkbox'] {
+		width: 15px;
+		height: 15px;
+		cursor: pointer;
+		accent-color: #65d000;
+	}
+
+	button {
+		padding: 0.75rem 2rem;
+		background: #65d000;
+		color: #1a1a1a;
+		border: none;
+		border-radius: 8px;
+		font-size: 1rem;
+		font-weight: 700;
+		cursor: pointer;
+		transition: background 0.15s, opacity 0.15s;
+		align-self: flex-start;
+	}
+
+	button:hover:not(:disabled) {
+		background: #54b800;
+	}
+
+	button:disabled {
+		opacity: 0.35;
+		cursor: not-allowed;
+	}
+
+	.zip-section {
+		margin-top: 1.5rem;
+		display: flex;
+		align-items: center;
+		gap: 1rem;
+		padding: 1rem 1.25rem;
+		background: #f0fce8;
+		border: 1.5px solid #65d000;
+		border-radius: 8px;
+	}
+
+	.zip-btn {
+		display: inline-block;
+		padding: 0.6rem 1.5rem;
+		background: #65d000;
+		color: #1a1a1a;
+		border-radius: 6px;
+		font-weight: 700;
+		font-size: 0.95rem;
+		text-decoration: none;
+		white-space: nowrap;
+		transition: background 0.15s;
+	}
+
+	.zip-btn:hover {
+		background: #54b800;
+	}
+
+	.zip-name {
+		font-size: 0.85rem;
+		color: #555;
+		overflow: hidden;
+		text-overflow: ellipsis;
+		white-space: nowrap;
+	}
+
+	.log-section {
+		margin-top: 2rem;
+	}
+
+	.log-header {
+		display: flex;
+		align-items: center;
+		gap: 0.5rem;
+		margin-bottom: 0.5rem;
+	}
+
+	.status-dot {
+		width: 8px;
+		height: 8px;
+		border-radius: 50%;
+		background: #ccc;
+		flex-shrink: 0;
+	}
+
+	.status-dot.running {
+		background: #f0a500;
+		animation: pulse 1.2s ease-in-out infinite;
+	}
+
+	.status-dot.done {
+		background: #65d000;
+	}
+
+	.status-dot.error {
+		background: #e03030;
+	}
+
+	@keyframes pulse {
+		0%, 100% { opacity: 1; }
+		50% { opacity: 0.25; }
+	}
+
+	.status-label {
+		font-size: 0.82rem;
+		color: #999;
+		text-transform: uppercase;
+		letter-spacing: 0.05em;
+	}
+
+	.log {
+		background: #fff;
+		border: 1px solid #d0d0c8;
+		border-radius: 8px;
+		padding: 0.75rem 1rem;
+		max-height: 450px;
+		overflow-y: auto;
+		font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
+		font-size: 0.78rem;
+		line-height: 1.6;
+	}
+
+	.line {
+		color: #aaa;
+		word-break: break-all;
+	}
+
+	.line.info {
+		color: #444;
+	}
+
+	.line.done {
+		color: #3a8000;
+		font-weight: 600;
+	}
+
+	.line.error {
+		color: #c00;
+		font-weight: 600;
+	}
+
+	.line.warn {
+		color: #b07000;
+	}
+</style>

src/routes/api/download/+server.js

@@ -0,0 +1,169 @@
+import { spawn, execFile } from 'child_process';
+import { existsSync, readdirSync, writeFileSync } from 'fs';
+import { join, basename } from 'path';
+import { promisify } from 'util';
+import { randomBytes } from 'crypto';
+import { convertSubtitleToMarkdown } from '$lib/subtitle.js';
+import { config, zipStore } from '$lib/server/store.js';
+
+const execFileAsync = promisify(execFile);
+const YTDLP = process.env.YTDLP_PATH ?? 'yt-dlp';
+const FFMPEG = process.env.FFMPEG_PATH ?? 'ffmpeg';
+
+export async function GET({ url, request }) {
+	const videoUrl = url.searchParams.get('url');
+	const audioOnly = url.searchParams.get('audio') === 'true';
+
+	if (!videoUrl) {
+		return new Response('Missing url parameter', { status: 400 });
+	}
+
+	const encoder = new TextEncoder();
+
+	const stream = new ReadableStream({
+		start(controller) {
+			// Accepts a string message or an object with extra fields
+			const send = (type, messageOrData) => {
+				try {
+					const payload = typeof messageOrData === 'string'
+						? { type, message: messageOrData }
+						: { type, ...messageOrData };
+					controller.enqueue(encoder.encode(`data: ${JSON.stringify(payload)}\n\n`));
+				} catch {}
+			};
+
+			const abortController = new AbortController();
+			request.signal.addEventListener('abort', () => abortController.abort());
+
+			runDownload(videoUrl, audioOnly, send, abortController.signal)
+				.catch(err => {
+					if (err.name !== 'AbortError' && err.code !== 'ABORT_ERR') {
+						send('error', err.message);
+					}
+				})
+				.finally(() => {
+					try { controller.close(); } catch {}
+				});
+		},
+		cancel() {}
+	});
+
+	return new Response(stream, {
+		headers: {
+			'Content-Type': 'text/event-stream',
+			'Cache-Control': 'no-cache',
+			'Connection': 'keep-alive'
+		}
+	});
+}
+
+async function runDownload(videoUrl, audioOnly, send, signal) {
+	send('info', 'Fetching video info…');
+	const { stdout } = await execFileAsync(YTDLP, [
+		'--get-filename', '--output', '%(title)s', '--no-playlist', videoUrl
+	], { signal });
+	const title = stdout.trim();
+
+	const token = config.zipAndSend ? randomBytes(8).toString('hex') : null;
+	const dirName = token ? `${token}-${title}` : title;
+	const outputDir = join(config.downloadDir, dirName);
+	const outputTemplate = join(outputDir, '%(title)s.%(ext)s');
+	send('info', `Title: ${title}`);
+
+	const subtitlePaths = [];
+	let videoPath = null;
+
+	await runProcess(YTDLP, [
+		'--format', 'bestvideo+bestaudio/best',
+		'--merge-output-format', 'mp4',
+		'--output', outputTemplate,
+		'--write-subs',
+		'--write-auto-subs',
+		'--sub-langs', 'en.*,de.*,orig',
+		'--sub-format', 'vtt',
+		'--write-thumbnail',
+		'--sleep-requests', '1',
+		'--ignore-errors',
+		'--no-playlist',
+		videoUrl
+	], line => {
+		send('log', line);
+		const sub = line.match(/\[info\] Writing video subtitles to: (.+)/);
+		if (sub) subtitlePaths.push(sub[1].trim());
+		const merge = line.match(/\[Merger\] Merging formats into "(.+)"/);
+		if (merge) videoPath = merge[1].trim();
+		const dest = line.match(/\[download\] Destination: (.+\.mp4)$/);
+		if (dest && !videoPath) videoPath = dest[1].trim();
+	}, signal);
+
+	// Fallback: scan directory for subtitle files
+	if (subtitlePaths.length === 0 && existsSync(outputDir)) {
+		for (const f of readdirSync(outputDir)) {
+			if (f.endsWith('.vtt') || f.endsWith('.srt')) {
+				subtitlePaths.push(join(outputDir, f));
+			}
+		}
+	}
+
+	for (const subPath of subtitlePaths) {
+		if (!existsSync(subPath)) continue;
+		send('info', `Converting: ${basename(subPath)}`);
+		try {
+			const md = convertSubtitleToMarkdown(subPath);
+			const mdPath = subPath.replace(/\.(vtt|srt)$/, '.md');
+			writeFileSync(mdPath, md, 'utf-8');
+			send('info', `Saved: ${basename(mdPath)}`);
+		} catch (err) {
+			send('warn', `Subtitle conversion failed: ${err.message}`);
+		}
+	}
+
+	if (audioOnly && videoPath && existsSync(videoPath)) {
+		const audioPath = videoPath.replace(/\.mp4$/, '.mp3');
+		send('info', `Extracting audio: ${basename(audioPath)}`);
+		await runProcess(FFMPEG, [
+			'-i', videoPath, '-vn', '-acodec', 'libmp3lame', '-q:a', '2', '-y', audioPath
+		], line => send('log', line), signal);
+		send('info', `Audio saved: ${basename(audioPath)}`);
+	}
+
+	if (config.zipAndSend && token) {
+		send('info', 'Creating ZIP…');
+		const zipPath = join(config.downloadDir, `${token}.zip`);
+		await createZip(outputDir, zipPath, title, send, signal);
+		zipStore.set(token, { zipPath, outputDir, filename: `${title}.zip` });
+		send('zip-ready', { token, filename: `${title}.zip` });
+		send('done', 'ZIP ready for download.');
+	} else {
+		send('done', 'Download complete!');
+	}
+}
+
+function createZip(sourceDir, zipPath, archiveDirName, send, signal) {
+	const script = join(process.cwd(), 'scripts', 'create_zip.py');
+	const args = [script, sourceDir, zipPath, archiveDirName];
+	if (config.zipExtraDir) args.push(config.zipExtraDir);
+	return runProcess('python3', args, line => send('log', line), signal);
+}
+
+function runProcess(cmd, args, onLine, signal, spawnOptions = {}) {
+	return new Promise((resolve, reject) => {
+		const proc = spawn(cmd, args, { signal, ...spawnOptions });
+		let settled = false;
+		const settle = (fn, val) => { if (!settled) { settled = true; fn(val); } };
+
+		const handleData = data =>
+			data.toString().split('\n').filter(Boolean).forEach(onLine);
+
+		proc.stdout.on('data', handleData);
+		proc.stderr.on('data', handleData);
+		proc.on('error', err => {
+			if (err.name === 'AbortError') settle(resolve, undefined);
+			else settle(reject, err);
+		});
+		proc.on('close', code => {
+			if (code === 0 || code === null) settle(resolve, undefined);
+			else settle(reject, new Error(`Process exited with code ${code}`));
+		});
+	});
+}

src/routes/api/zip/+server.js

@@ -0,0 +1,43 @@
+import { createReadStream, statSync } from 'fs';
+import { rm } from 'fs/promises';
+import { Readable } from 'stream';
+import { config, zipStore } from '$lib/server/store.js';
+
+export async function GET({ url }) {
+	const token = url.searchParams.get('token');
+	if (!token) return new Response('Missing token', { status: 400 });
+
+	const entry = zipStore.get(token);
+	if (!entry) return new Response('Not found or already downloaded', { status: 404 });
+
+	// Single-use token — remove immediately
+	zipStore.delete(token);
+
+	let size;
+	try {
+		size = statSync(entry.zipPath).size;
+	} catch {
+		return new Response('ZIP file not found on server', { status: 404 });
+	}
+
+	const nodeStream = createReadStream(entry.zipPath);
+
+	if (config.deleteAfterSend) {
+		nodeStream.on('close', () => {
+			setTimeout(async () => {
+				await rm(entry.outputDir, { recursive: true, force: true }).catch(() => {});
+				await rm(entry.zipPath, { force: true }).catch(() => {});
+			}, config.deleteDelay);
+		});
+	}
+
+	const safeFilename = entry.filename.replace(/[^\w\s.\-()]/g, '_');
+
+	return new Response(Readable.toWeb(nodeStream), {
+		headers: {
+			'Content-Type': 'application/zip',
+			'Content-Disposition': `attachment; filename="${safeFilename}"`,
+			'Content-Length': String(size),
+		}
+	});
+}

start.sh

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+# yt-dlf startup script
+#
+# Environment variables:
+#   PORT              Port to listen on (default: 3000)
+#   ORIGIN            Public URL of this server, e.g. http://myserver:3000 (required in production)
+#   YTDLP_PATH        Path to yt-dlp binary (default: yt-dlp, must be on PATH)
+#   FFMPEG_PATH       Path to ffmpeg binary (default: ffmpeg, must be on PATH)
+#
+#   DOWNLOAD_DIR      Directory where downloaded files are stored (default: ~/YouTube)
+#
+#   ZIP_AND_SEND      Set to "true" to ZIP the downloaded files and offer them as a
+#                     browser download instead of (only) saving them on the server.
+#                     A random prefix is added to the directory name to avoid collisions
+#                     when multiple users download the same video simultaneously.
+#                     (default: false)
+#
+#   DELETE_AFTER_SEND When ZIP_AND_SEND=true: delete the files from the server after
+#                     the ZIP has been sent to the browser. (default: false)
+#
+#   DELETE_DELAY      Seconds to wait before deleting files after the ZIP has been sent.
+#                     Only relevant when DELETE_AFTER_SEND=true. (default: 0)
+#
+#   ZIP_EXTRA_DIR     Optional directory whose files are added to every ZIP alongside
+#                     the downloaded files. Subdirectory structure within ZIP_EXTRA_DIR
+#                     is preserved. Only used when ZIP_AND_SEND=true. (default: none)
+
+export PORT="${PORT:-3000}"
+export ORIGIN="${ORIGIN:-http://localhost:${PORT}}"
+
+# Uncomment and adjust the lines below to configure:
+# export DOWNLOAD_DIR="$HOME/YouTube"
+# export ZIP_AND_SEND="false"
+# export ZIP_EXTRA_DIR="/path/to/extra/files"
+# export DELETE_AFTER_SEND="false"
+# export DELETE_DELAY="0"
+
+exec node build/index.js

static/robots.txt

@@ -0,0 +1,3 @@
+# allow crawling everything by default
+User-agent: *
+Disallow:

svelte.config.js

@@ -0,0 +1,17 @@
+import adapter from '@sveltejs/adapter-node';
+
+/** @type {import('@sveltejs/kit').Config} */
+const config = {
+	compilerOptions: {
+		// Force runes mode for the project, except for libraries. Can be removed in svelte 6.
+		runes: ({ filename }) => (filename.split(/[/\\]/).includes('node_modules') ? undefined : true)
+	},
+	kit: {
+		// adapter-auto only supports some environments, see https://svelte.dev/docs/kit/adapter-auto for a list.
+		// If your environment is not supported, or you settled on a specific environment, switch out the adapter.
+		// See https://svelte.dev/docs/kit/adapters for more information about adapters.
+		adapter: adapter()
+	}
+};
+
+export default config;

vite.config.js

@@ -0,0 +1,14 @@
+import { sveltekit } from '@sveltejs/kit/vite';
+import { defineConfig } from 'vite';
+
+export default defineConfig({
+	plugins: [sveltekit()],
+	server: {
+		port: parseInt(process.env.PORT ?? '5173'),
+		strictPort: false
+	},
+	preview: {
+		port: parseInt(process.env.PORT ?? '4173'),
+		strictPort: false
+	}
+});