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KFR - Fast, modern C++ DSP framework

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https://www.kfrlib.com

KFR is an open source C++ DSP framework that contains high performance building blocks for DSP, audio, scientific and other applications. It is distributed under dual GPLv2/v3 and commercial license.

KFR6

New features, performance improvements, easier setup.

:arrow_right: What's new in KFR6

:arrow_right: Upgrade from a previous version

Our other projects

🟣 Brisk is a cross-platform C++20 GUI framework featuring MVVM architecture, reactive capabilities, and scalable, accelerated GPU rendering. (GPL/Commercial)

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KFR Installation

Compiler support:

KFR has no external dependencies except for a C++17-compatible standard C++ library. CMake is used as the build system.

Clang is highly recommended and proven to provide the best performance for KFR. You can use Clang as a drop-in replacement for both GCC on Linux and MSVC on Windows. On macOS, Clang is the default compiler and included in the official Xcode toolchain.

Note: Building the DFT module currently requires Clang due to internal compiler errors and a lack of optimization in GCC and MSVC.

:arrow_right: See Installation docs for more details

Features

:star2: — new in KFR6

FFT/DFT

Optimized DFT implementation for any size (non-power of two sizes are supported)
DFT performance is on par with the most performant implementation currently available See Benchmarks
Real forward and inverse DFT
:star2: Multidimensional complex and real DFT
Discrete Cosine Transform type II (and its inverse, also called DCT type III)
Convolution using FFT
Convolution filter

:arrow_right: See also How to apply FFT with KFR

DSP

IIR filter design
- Butterworth
- Chebyshev type I and II
- Bessel
- Lowpass, highpass, bandpass and bandstop filters
- Conversion of arbitrary filter from {Z, P, K} to SOS format (suitable for biquad function and filter)
Biquad filter See Benchmarks
Simple biquad filter design
FIR filter design using window method
Loudness measurement according to EBU R128
Window functions: Triangular, Bartlett, Cosine, Hann, Bartlett-Hann, Hamming, Bohman, Blackman, Blackman-Harris, Kaiser, Flattop, Gaussian, Lanczos, Rectangular
Sample rate conversion with configurable quality and linear phase
Oscillators, fast incremental sine/cosine generation, Goertzel algorithm, fractional delay

Base

Tensors (multidimensional arrays)
:star2: .npy support (reading/writing)
:star2: Matrix transpose
Statistical functions
Random number generation
Template expressions (See examples)
Ring (Circular) buffer
:star2: Windows arm64 support
:star2: Emscripten (wasm/wasm64) support

Math

Mathematical functions such as sin, log and cosh built on top of SIMD primitives
Most of the standard library functions are re-implemented to support vector of any length and data type

SIMD

vec<T, N> class and related functions that abstracts cpu-specific intrinsics
All code in the library is optimized for Intel, AMD (SSE2, SSE3, SSE4.x, AVX and AVX2 and AVX512) and ARM, AArch64 (NEON) processors
All data types are supported including complex numbers
All vector lengths are also supported. vec<float,1>, vec<unsigned,3>, vec<complex<float>, 11> all are valid vector types in KFR
Sorting

IO

Audio file reading/writing
WAV
FLAC
MP3

Multiarchitecture

The multiarchitecture mode enables building algorithms for multiple architectures with runtime dispatch to detect the CPU of the target machine and select the best code path