Video Downloader - Download Videos with yt-dlp

Download videos, audio, or subtitles from YouTube, Bilibili, Twitter, and 1000+ other sites using yt-dlp.

When to Use

• User asks to download a video
• User asks to download or extract audio
• User asks to download subtitles
• User provides a video URL (YouTube, Bilibili, Twitter, etc.)
• User wants to specify video quality (720p, 1080p, etc.)

Prerequisites - Auto Install

IMPORTANT: Before any download, check and install dependencies automatically.

Step 0: Check and Install Dependencies

# Check if yt-dlp is installed, install if missing
if ! command -v yt-dlp &>/dev/null; then
  echo "Installing yt-dlp..."
  brew install yt-dlp
fi

# Check if ffmpeg is installed, install if missing
if ! command -v ffmpeg &>/dev/null; then
  echo "Installing ffmpeg..."
  brew install ffmpeg
fi

# Verify installation
yt-dlp --version && echo "yt-dlp: ready"
ffmpeg -version 2>&1 | head -1 && echo "ffmpeg: ready"

Run this check every time before downloading. Install automatically without asking user.

Instructions for Agent

Step 1: Ensure Dependencies Installed

Run the prerequisite check above. If yt-dlp or ffmpeg is missing, install via brew install yt-dlp ffmpeg.

Step 2: Parse User Intent

Identify what the user wants:

Step 3: Build Command

Base command structure:

yt-dlp [OPTIONS] "URL"

Common options by intent:

1. Basic video download (best quality):

yt-dlp -o "%(title)s.%(ext)s" "URL"

2. Audio only (MP3):

yt-dlp -x --audio-format mp3 -o "%(title)s.%(ext)s" "URL"

3. Specific quality (e.g., 720p):

yt-dlp -f "bestvideo[height<=720]+bestaudio/best[height<=720]" -o "%(title)s.%(ext)s" "URL"

4. Video with embedded subtitles:

yt-dlp --write-subs --sub-lang en,zh-Hans,zh-Hant --embed-subs -o "%(title)s.%(ext)s" "URL"

5. Subtitles only (no video):

yt-dlp --write-subs --write-auto-subs --sub-lang en,zh-Hans,zh-Hant --skip-download -o "%(title)s" "URL"

Step 4: Execute and Report

Run the command and report:

• File name and location
• File size (if available)
• Any warnings or errors

Command Reference

Response Guidelines

• Always confirm what will be downloaded before starting
• Show download progress or final result
• Report the output file name and location
• If download fails, explain the error and suggest solutions

Error Handling