oversimple

Oversimple is a C++17 library for audio oversampling, which tries to offer a simple api.

Oversimple wraps two of the best resampling libraries available:

• HIIR, by Laurent De Soras for minimum phase antialiasing. HIIR only implements power of two resampling.

• and r8brain-free-src by Aleksey Vaneev, for linear phase antialiasing.

Both libraries use SIMD instructions for both single and double precision floating point numbers on all platforms where they are supported (including double precision on ARM AArch64).

Aligned memory and interleaved buffers needed by the simd code in HIIR are managed using avec.

Usage

Add everything to your project except for the content of the test folders and the .cpp files in avec/vectorclass.

Add to your include paths the directory in which you put this repository and its subdirectories r8brain, avec, and avec/vectorclass.

To use PFFFT with double precision, define R8B_PFFFT_DOUBLE=1 in r8brain/r8bconf.h or as a preprocessor definition. See r8brain/README.md for more details.

Dependencies

• pthread on *nix (only r8brain).

Tests

$ cd test
$ ./run-tests.sh

builds and runs the doctest-based test suite for every architecture this host supports. On Apple Silicon that's both arm64 and x86_64 (via Rosetta); on Intel and Linux it's just the host arch.

The suite measures round-trip SNR per channel for each oversampler (FIR linear-phase, IIR minimum-phase, the Oversampling wrapper) and asserts against conservative per-test thresholds (≥60 dB steady-state for FIR sine and Oversampling linear-phase sine, ≥60 dB IIR DC convergence, permissive first-block thresholds during FIR warm-up). The previous test only printed SNR to stdout without asserting — a 50 dB regression would have been invisible.

Both float and double precisions are tested for every (test, arch) pair.

Documentation

The documentation, available at https://unevens.github.io/oversimple/, can be generated with Doxygen running

$ doxygen doxyfile.txt