µQOA (Micro QOA) is an encoder/decoder implementation for the Quite OK Audio Format (QOA), targeted at non-desktop environments (e.g. microcontrollers).
µQOA can be ideal if a minimal lossy audio codec is needed in a small environment with reasonable storage (QOA achieves 3.2 bits per sample).
Features include:
- < 400 bytes compiled code and data (decoder only, ARMv7)
- Explicit integer width for calculation
- Agnostic on file formats; works directly with data slices
#define uQOA_IMPL // Define in one and only one place
#include "uqoa.h" // Include where necessaryThe structure qoa_lms holds a 16-byte internal state. There is one function for decoding a 64-bit slice into 20 samples, and another for the other way round. Refer to test.c for a minimal example.
Rather than the standard QOA file format, µQOA works with individual 64-bit slices. The internal LMS filter state can be dumped occasionally to support random seeking and avoid overflows.
qoa_conv.c is a program that converts between binary raw sample data and a QOA data format where the state is dumped every 256 slices. It can be combined with FFmpeg to produce data for on-site use. Refer to the code for details.