MIxer SPDIF V1.0

Asynchronous S/PDIF Mixer

"Asynchronous SPDIF Mixer" is a hardware and software project designed to synchronize and mix up to three asynchronous S/PDIF streams into a single 48 kHz output stream.
The system compensates for drift between sources and uses interpolation to ensure smooth and artifact-free audio transitions.
The project includes USB-MIDI control, allowing real-time mixing of the three audio channels via an external MIDI controller or any MIDI-compatible software.

The software, developed in C++ with CubeIDE, is optimized for real-time audio processing and runs on an STM32H743 microcontroller.
A custom electronic board, designed with KiCad, provides a dedicated hardware platform for this solution.

📋 New Evolutions

Recent updates to the project include:

• 🔄 Enhanced Drift Compensation: A new algorithm has been implemented for compensating drifts in the input frequencies, ensuring more precise synchronization across streams.
• 🎛️ Advanced Mixing Controls: Mixing between the three inputs can now be adjusted in real-time via MIDI over USB, complemented by a Python-based control panel for intuitive configuration. Mix settings are automatically saved and recalled as presets stored directly in flash memory for persistent, non-volatile access.

👤 Author

This project is developed by DAD Design.

📄 License

This project is licensed under the MIT License.

✨ Features

• Synchronization of Asynchronous S/PDIF Streams: The project synchronizes three input audio streams, each potentially running at different sample rates ( 48kHz, 44.1kHz, 32kHz), into a unified output stream at 48kHz.
• Clock Drift Compensation: Drift between the input streams is handled through periodic drift factor recalculation, ensuring the output remains smooth and synchronized.
• 🎛️ Real-Time Mixing Controls: Adjustable mixing levels for the three inputs via any USB-MIDI interface. A Python control panel included as an example for easy configuration.
• 💾 Preset Memorization: Mix settings are automatically saved and can be recalled as presets stored in flash memory for quick, persistent access.

🛠️ Hardware Platform

The KiCAD folder contains the schematics and PCB files for the project's hardware. These files were created using KiCAD version 9.0.

🔧 Development Environment

The project is developed and compiled using the CubeIDE environment provided by STMicroelectronics. CubeIDE is a fully integrated development environment (IDE) that supports STM32 microcontrollers and provides tools for debugging, flashing, and developing embedded systems.