Real-time audio spectrum analyzer and waterfall display built with C++17, ImGui, SDL2, and OpenGL. Runs natively on Linux and Windows, and in the browser via WebAssembly.

Beware, this thing is entirely LLM-generated! I've barely looked at the code! Anthropic had a promo for Claude, so I utilized it to make this clone of baudline, which is a very powerful (and proprietary) tool, but sadly it's been seemingly abandoned for years, not that it would need anything. My hope was to put together something similar, using a more modern stack. It is not (yet) a fully-featured replacement, but it's good enough for me.

Web preview

You can find the Web version here, delivered in 870 kB: https://ericek111.github.io/baudmine/

(If you allow access to "all microphones", you can switch between the input devices in the File menu.)

Features

Signal Processing

FFT sizes from 256 to 65,536 points with configurable overlap of bins for precise speed control of the waterfall.
Window functions: Hann, Hamming, Blackman, Blackman-Harris, Kaiser (configurable beta), Flat Top, Rectangular

Input Sources

Live audio from system input devices
Multi-device mode: use up to 8 devices simultaneously, each mapped to a channel
File playback: WAV, Float32/Int16/Uint8 I/Q formats

Visualization

Spectrum plot
Scrolling waterfall display that can be zoomed and panned
Linear and logarithmic frequency scales
Additive color blending for multi-channel display
Peak hold with adjustable decay rate

Analysis

Dual cursors with frequency and magnitude readout
Automatic snap-to-peak
Peak detection with configurable threshold, separation, and frequency range (it shows the center frequency of the peak-detected FFT bin)
Peak trace on the waterfall
Delta measurements between cursors

Math Channels

Unary: Negate, Absolute, Square, Cube, Square Root, Log
Binary: Add, Subtract, Multiply, Phase, Cross-correlation
Custom colors per math channel

Interface

DPI-aware UI with auto-detection and manual scaling (100-300%)
Touch gesture support in the waterfall (pan and pinch-to-zoom)
The most important settings persist across sessions

Building

Linux

# Install dependencies (Debian/Ubuntu)
sudo apt install build-essential cmake pkg-config libsdl2-dev libfftw3-dev libsndfile1-dev libgl-dev

cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build -j$(nproc)

Windows (MSVC + vcpkg)

vcpkg install sdl2 fftw3 "libsndfile[core]" --triplet x64-windows

cmake -B build -DCMAKE_BUILD_TYPE=Release `
    -DCMAKE_TOOLCHAIN_FILE="$env:VCPKG_INSTALLATION_ROOT/scripts/buildsystems/vcpkg.cmake" `
    -DVCPKG_TARGET_TRIPLET=x64-windows
cmake --build build --config Release