Architecture Overview

Velion is a professional Digital Audio Workstation (DAW) developed in C++20 with Qt6 as the GUI framework. The architecture is modular, separating audio processing, UI, plugin hosting, MIDI, and core services into distinct modules.

C++20

Core Language

Custom Qt6

GUI Framework

VST3 SDK

Plugin Hosting

CMake

Build System

Signal Pipeline

Audio Input

Mixer Engine

VST3 Plugins

ASIO Output

Core Technology

Audio Engine

32-bit floating point precision with ultra-low latency below 1ms. Sample rates up to 768kHz for crystal clear audio.

The mixer supports unlimited tracks, each with 8 VST3 insert slots, 5-band parametric EQ, compressor, gain, pan, and 2 send slots. Advanced features include SIMD-optimized DSP (AVX2/AVX-512), zero-copy audio graphs, and work-stealing schedulers.

Professional ASIO driver support with WDM/KS, WASAPI, DirectSound backends. Adaptive buffer management and real-time safety guarantees.

32-Bit Float

<1ms Latency

768kHz Sample Rate

∞ Tracks

Plugin System

Full VST3 hosting with the official Steinberg VST3 SDK. Also supports AU (macOS), LV2, and AAX plugin formats.

The PluginRegistry manages both internal (16 built-in) and external VST3 plugins. The VST3PluginHost provides real audio processing, MIDI event handling, parameter caching, and editor view support.

A plugin sandbox ensures stability by isolating third-party plugins with configurable timeouts and safety modes.

VST3 Steinberg

AU macOS

LV2 Linux

AAX Avid

MIDI 2.0

Full MIDI 2.0 support including UMP (Universal MIDI Packet), MIDI-CI (Capability Inquiry), and MPE (MIDI Polyphonic Expression).

The Piano Roll provides professional MIDI editing with note manipulation, velocity editing, and automation curves.

UMP Universal MIDI Packet

CI Capability Inquiry

MPE Polyphonic Expression

User Experience

User Interface

Qt6-based modern interface with a pixel-perfect dark theme inspired by high-end DAWs. Complete with glow effects, animated transitions, and gradient fills.

The Theme Engine supports 5 themes: Dark, Light Pro, High Contrast, OLED Black, and custom user themes. The design system defines colors, sizes, and spacing in a centralized constants file.

Custom QPainter widgets: TransportButton, TimeDisplay, MeterWidget, KnobWidget, FaderWidget, ChannelStrip, ClipWidget, PlayheadWidget, TimelineGrid.

Dark Light Pro High Contrast OLED Black Custom

Built-in Instruments

6 built-in instruments and effects: Stratus Synth (analog-style synthesizer), Pulse Drum Machine, Mosaic Sampler, Choir Vocoder, Lattice Additive Synth, Linear Phase EQ, and Convolution Reverb. All instruments are included for free.

🎹 Stratus Synth

🥁 Pulse Drum

🎸 Mosaic Sampler

🎤 Choir Vocoder

✨ Lattice Synth

🌊 Convolution Reverb

AI Features

Intelligent stem separation, audio-to-MIDI conversion, smart quantizer, tempo detection, and spectral analysis. AI-powered mixing assistance and mastering tools.

Stem Separation Audio-to-MIDI Smart Quantizer Tempo Detection Spectral Analysis Mixing Assistant

Platform Support

Cross-Platform

Available on Windows 10/11, macOS 11+, and Linux (Ubuntu 20.04+). Projects are fully compatible across all platforms. Native Apple Silicon support.

Windows 10 / 11

macOS 11+

Linux Ubuntu 20.04+

Documentation