Freeware Advanced Audio (AAC) Decoder including SBR decoding http://www.audiocoding.com/
FAAD2 is a HE, LC, MAIN and LTP profile, MPEG2 and MPEG-4 AAC decoder. FAAD2 includes code for SBR (HE AAC) decoding.
License: GPL license.
Download: https://github.com/knik0/faad2.git
Version: Commits on Dec 12 2019, update README esp. WRT directory structure
Free Lossless Audio Codec
License: GPL license.
Download: https://github.com/xiph/flac.git
Version: Commits on Dec 27 2019, Fix nullptr dereference in FLAC++
Fixed-point MP3 decoder
Download: https://github.com/tonyfg/mp3-launchpad-stellaris.git
Version: Commits on Dec 21 2012, Initial commit
MPEG audio decoder library
License: GPLv2 license.
Download: https://sourceforge.net/projects/mad/files/libmad/0.15.1b/
Version: 0.15.1b
libwav is a simple and tiny C library for reading or writing PCM wave (.wav) files.
License: MPLv2 license.
Download: https://github.com/brglng/libwav.git
Version: Commits on May 31 2019, Update .ccls
Minimalistic MP3 decoder single header library
License: CC0-1.0 license.
Download: https://github.com/lieff/minimp3.git
Version: Commits on Jan 27 2020, Support index binary search on seek.