# 📺 Bilibili Video Downloader

> A Python tool to **download videos from Bilibili (B站)** with WBI signature authentication, multi-quality selection, and optional ffmpeg audio+video merging.

**Bilibili Video Downloader** downloads videos from Bilibili by BV URL. It implements the WBI signature algorithm for API authentication, picks the best available MP4 quality, and supports downloading with **aria2** (fast) or pure-Python fallback, then optionally merges audio & video with **ffmpeg**.

---

## 📦 Files

| File | Description |
|------|-------------|
| `bilibili_downloader.py` | Standard version — fill in your `sessdata` cookie manually |
| `bilibili_downloader_auto.py` | Auto version — edit the `sessdata` variable inside the script |

> Both files have identical features. The difference is only how the cookie is provided.

---

## ✨ Features

| Feature | Description |
|---------|-------------|
| 🔑 **WBI Signature** | Implements Bilibili WBI signing algorithm for authenticated API calls |
| 🎞️ **Best MP4 Quality** | Automatically picks the highest available MP4 stream |
| 🧪 **URL Test** | Verifies content URL accessibility before download |
| ⚡ **aria2 Support** | Uses aria2 for fast parallel downloads (if installed) |
| 🐍 **Pure-Python Fallback** | If aria2 is unavailable, downloads directly via Python |
| 🎬 **ffmpeg Merge** | Merges separate video + audio streams into one file |
| 📄 **Info Fetch** | Retrieves video metadata (title, etc.) via BV URL |

---

## 🚀 Quick Start

### Prerequisites
- Python 3.7+
- `requests` library
- **Cookie** (`sessdata`) — required for Bilibili access
- Optional: `aria2` (fast), `ffmpeg` (audio/video merge)

### Install

```bash
pip install requests
```

### Setup Cookie

1. Log in to Bilibili in your browser
2. Open DevTools → Application → Cookies → find `sessdata`
3. Paste it into the script:

**`bilibili_downloader.py`** (fill at runtime or edit variable):
```python
sessdata = ""  # <-- paste your sessdata
```

**`bilibili_downloader_auto.py`** (edit variable directly):
```python
sessdata = '填写你的Cookie'  # <-- replace with your sessdata
```

### Run

```bash
python bilibili_downloader.py
# or
python bilibili_downloader_auto.py
```

Enter a Bilibili video BV URL when prompted (e.g. `BV1xx411c7mD`).

---

## 📁 Project Structure

```
Bilibili-Video-Downloader/
├── bilibili_downloader.py       # Standard version
├── bilibili_downloader_auto.py  # Auto version (cookie in script)
└── README.md                    # This document
```

---

## 📄 License

This project is licensed under the **MIT License**. See [LICENSE](LICENSE) for details.

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## ⚠️ Disclaimer

> This tool is for **personal learning and research only**. Please respect Bilibili's Terms of Service and content creators' copyright. Do not redistribute downloaded content. Use at your own risk.