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MegaDownloader is a Java Swing GUI application for downloading videos and audio from YouTube using yt-dlp. This guide will walk you through installing all prerequisites and building the application.

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Prerequisites

Before installing MegaDownloader, ensure you have the following installed on your system:
1

Java 24 or higher

MegaDownloader requires Java 24 as specified in the pom.xml configuration:
<properties>
    <maven.compiler.release>24</maven.compiler.release>
</properties>
Verify your Java installation:
java -version
If you need to install Java 24, download it from the Oracle JDK website or use your system’s package manager.
2

Apache Maven

Maven is required for building the project and managing dependencies.Verify Maven is installed:
mvn -version
If not installed, download it from the Maven website.

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Required External Tools

MegaDownloader relies on two external tools for downloading and processing media:
1

Install yt-dlp

yt-dlp is the core download engine used by MegaDownloader.
  1. Download the yt-dlp executable from the official repository:
  2. Place yt-dlp.exe (Windows) or yt-dlp (Linux/Mac) in a known directory
  3. Note the full path - you’ll need this during first-time configuration
The application stores this path in config.txt and reads it using the getYtDlpPath() method from MainPanel.java:174.
2

Install FFmpeg (Required for audio extraction)

FFmpeg is essential for extracting audio from videos and converting formats.
  1. Download FFmpeg from:
  2. Extract the archive and locate ffmpeg.exe and ffprobe.exe (or the non-.exe versions on Unix systems)
  3. Important: Place both executables in the same directory as yt-dlp
MegaDownloader automatically detects FFmpeg when it’s in the same directory as yt-dlp using the hybrid detection system in MainPanel.java:222-254:
private String getFfmpegLocation() {
    String ytdlpPath = getYtDlpPath();
    if (ytdlpPath != null) {
        File ytdlpFile = new File(ytdlpPath);
        File ytdlpDir = ytdlpFile.getParentFile();
        
        if (ytdlpDir != null) {
            File ffmpegExe = new File(ytdlpDir, "ffmpeg.exe");
            File ffprobeExe = new File(ytdlpDir, "ffprobe.exe");
            
            if (ffmpegExe.exists() && ffprobeExe.exists()) {
                return ytdlpDir.getAbsolutePath();
            }
        }
    }
}
If you attempt audio extraction without FFmpeg, you’ll see a warning dialog (MainPanel.java:524-537) prompting you to install it.

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Building the Application

Once all prerequisites are installed, build MegaDownloader from source:
1

Clone or download the source code

Navigate to the project directory:
cd /path/to/megadownloader
2

Compile with Maven

Compile the project and resolve dependencies:
mvn clean compile
This command:
  • Downloads all dependencies (FlatLaf, Jackson, custom components)
  • Compiles Java sources from src/main/java/com/borjaalmazan/entrega1_1/
  • Validates the build configuration
3

Package as JAR (Optional)

Create an executable JAR with all dependencies:
mvn package
The Maven Shade plugin will create an uber-JAR at target/megadownloader-1.0-SNAPSHOT.jar with the main class set to com.borjaalmazan.entrega1_1.Main.
4

Run the application

Run directly with Maven:
mvn exec:java
Or run the packaged JAR:
java -jar target/megadownloader-1.0-SNAPSHOT.jar

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First-Time Configuration

When you first launch MegaDownloader, you’ll need to configure the yt-dlp path:
1

Configuration prompt

On first launch, you’ll see this dialog (Main.java:124-133):
if (!configFile.exists()) {
    JOptionPane.showMessageDialog(this,
        "No configuration found.\n" +
        "To be able to use the app, please go to Edit > Preferences to set the yt-dlp path.",
        "Configuration Required",
        JOptionPane.INFORMATION_MESSAGE);
}
2

Set yt-dlp location

  1. Click Edit > Preferences in the menu bar
  2. Click Change location button
  3. Navigate to and select your yt-dlp.exe file
  4. The path will appear in the preferences panel
3

Set download directory (Optional)

By default, files download to the project directory. To change this:
  1. In Preferences, click Change Download directory
  2. Select your preferred download folder
  3. This path is stored in config.txt as downloadDir:"/your/path"
4

Save configuration

Click Save to write settings to config.txt:
path:"C:\tools\yt-dlp.exe"
downloadDir:"C:\Users\YourName\Downloads"
The configuration file is read by PreferencesPanel.java:127-151 on startup and persists between sessions.

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Manual FFmpeg Configuration

If FFmpeg is installed in a different location than yt-dlp:
  1. Open config.txt in a text editor
  2. Add the FFmpeg path:
path:"C:\tools\yt-dlp.exe"
downloadDir:"C:\Users\YourName\Downloads"
ffmpegPath:"C:\ffmpeg\bin"
  1. Save and restart the application
The application will check this manual path as a fallback (MainPanel.java:239-250).

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Verifying Installation

To verify everything is set up correctly:
  1. Launch MegaDownloader
  2. Log in with your credentials
  3. Go to Edit > Preferences
  4. Confirm the yt-dlp path is displayed (not “Not configured”)
  5. Try downloading a test video to confirm functionality

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Dependencies

MegaDownloader uses the following libraries (automatically managed by Maven):
  • FlatLaf 3.6.2 - Modern dark theme for the UI
  • Jackson 3.0.0 - JSON parsing for API communication
  • Custom MediaPollingComponent - API integration for media management
These are defined in pom.xml:14-30 and downloaded automatically during the build process.

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Troubleshooting

If you encounter issues during installation:
  • Ensure Java 24+ is properly installed and in your PATH
  • Verify yt-dlp is executable and not blocked by antivirus
  • Place FFmpeg executables directly in the yt-dlp directory for auto-detection
  • Check file permissions if configuration fails to save
  • Review console output for detailed error messages

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Next Steps

Now that MegaDownloader is installed and configured, proceed to the Quickstart Guide to download your first video.

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