Cool Player

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Inspiration

Listening to high-resolution FLAC files on an iPhone or iPad often involves cumbersome workflows, as native support is limited compared to standard Apple Music formats. I developed Cool Player to bridge this gap, allowing Mac users to easily prepare their high-resolution audio libraries for seamless, high-fidelity playback on the go. My goal was to create a tool that makes the high-res experience on iPhone and iPad much simpler and more accessible, providing a much higher standard of audio quality for mobile listeners.

What it does

Cool Player is a powerful macOS application that effortlessly converts FLAC files and folders to ALAC (supporting up to 24-bit / 192kHz). Beyond simple conversion, it serves as the essential tool for audiophiles to optimize their music libraries for mobile devices. It analyzes original audio information, retains album art and metadata, and perfectly saves LRC time-synced lyrics. It also features a built-in player to verify the converted files and keeps a comprehensive task history, ensuring your music is ready for your iPhone or iPad.

How we built it

We developed Cool Player specifically for macOS using Swift and AVFoundation. We started by designing an intuitive UI for easy file and folder management. Then, we implemented an audio analysis module and built a robust conversion pipeline that guarantees seamless ALAC output alongside its corresponding artwork and LRC data.

Challenges we ran into

The most significant challenge was managing system resources efficiently during the batch conversion of massive, high-resolution audio files. We had to implement complex asynchronous processing and memory optimization techniques to prevent the app from freezing or slowing down, ensuring the conversion and playback features ran stably without conflicts.

Accomplishments that we're proud of

We are incredibly proud of achieving flawless, lossless 24-bit / 192kHz conversion while keeping the original metadata and LRC lyrics completely intact. Building a stable architecture that maintains a smooth, crash-free user experience even during heavy batch workloads was a major milestone for us.

What we learned

We gained a deep understanding of handling high-resolution audio data losslessly within the macOS environment. We also significantly expanded our knowledge of audio metadata parsing, structural data management, interacting with the file system, and optimizing asynchronous tasks for better performance.

What's next for Cool Player

We plan to expand our format support beyond FLAC, enhance the built-in audio player with more advanced features, and further optimize the core conversion engine to provide even faster processing speeds for massive music libraries.

Built With

• avfoundation
• macos
• swift