Swing Music WebSocket Player

This project enables local music playback for the Swing Music web app, utilizing either browser APIs or a websocket connection for the device's default audio output via vlc. The services are designed to run on a headless Raspberry Pi 5.

With this setup, you can queue music from a Vue front-end running on your MacBook's browser and have it play on speakers connected to the Raspberry Pi. A 'keep alive' mechanism has been implemented on both the front-end and the server to ensure continuous music playback on the Pi even if the MacBook instance disconnects.

The Vue front-end hands over the playback queue to the server as an array of filepaths and the complete tracklist JSON object. The websocker server uses the filepaths array for playback. On reverse handover or when a new client connects, the tracklist object is passed to the client for populating the UI (queue, track metadata etc.).

Development

This server relies on three main packages: VLC, Starlette, and Uvicorn.

You'll need to have VLC (or at least the libvlc5 package) installed on your system. Install the Python packages from the requirements.txt file.

Run using:

# In development
python3 player.py
# In production
uvicorn player:app --host 0.0.0.0 --port 1971

The services run on these ports:

• Core Swing Music App: http://localhost:1980
• Front-end Vue Client: http://localhost:5173
• WebSocket Server: ws://localhost:1971

Note

At the moment, this project only works with my fork of the swingmusic webclient.

Why this project

This project was created to enable controlling music playback on a headless Raspberry Pi, which runs the core Swing Music app and is connected to a home theatre system. It allows any device connected to the home network (phone, tablet, computer) to control the playback queue on the server.

Why VLC and not ffmpeg? The core swingmusic app already uses ffmpeg for silence detection so it makes sense for this server to use ffplay for playback control. Hence the player_ffmpeg.py script.

Unfortunately, in the ffmpeg version, both seek() and set_volume() functions work by stopping the current ffplay process and immediately starting a new one at the correct timestamp or with the new volume. This causes a noticeable audio gap and stutter during these operations. These are fundamental limitations of controlling playback in ffplay processes.

In comparison, VLC does a far better job in terms of playback (which makes sense).