how can i make a mac app that downloads a yt video's audio and thumbnail. and after that it adds it to your apple music library.

To create a Mac app that downloads a YouTube video's audio and thumbnail, and then adds it to your Apple Music library, you would need to integrate several technologies and APIs. Here's a high-level approach based on the content presented at WWDC:

1. Downloading Audio and Thumbnail:

   • You can use a downloader extension in Xcode to handle background downloads. The session Discover Apple-Hosted Background Assets discusses how to use background assets to download files efficiently.

2. Audio Processing:

   • To handle audio files, you might want to explore the session Enhance your app’s audio recording capabilities, which covers audio mix and processing capabilities. This could be useful if you need to process the audio before adding it to Apple Music.

3. Integrating with Apple Music:

   • While there isn't a direct mention of adding content to Apple Music in the provided context, you would typically use the MusicKit API to interact with the Apple Music library. This would involve using the MusicKit framework to add the downloaded audio to the user's library.

4. Using Xcode and Swift:

   • The session Platforms State of the Union highlights the use of Xcode and Swift for building apps. You can leverage Swift and Xcode's capabilities to develop the app's logic and user interface.

5. Machine Learning for Enhancements:

   • If you want to enhance the app with machine learning, such as for audio analysis or thumbnail recognition, the session What’s new in Create ML provides insights into using Create ML for building custom models.

This approach combines downloading capabilities, audio processing, and integration with Apple Music, leveraging the tools and frameworks discussed at WWDC.