ISO/IEC 23003-3) exhale (encoder only; open source) IETF standards: Opus (RFC 6716) based on SILK vocoder and CELT codec libopus FFmpeg (decoding and experimental encoding) IETF Internet Draft IPMR Speech Codec - used in Spirit DSP's TeamSpirit Voice&Video Engine Neural audio codecs Lyra (codec) - used in Google Duo Lyra V2 - based on SoundStream neural codec Satin (used by Microsoft Teams) Facebook EnCodec General Adaptive differential pulse-code modulation (ADPCM, also called adaptive delta pulse-code modulation) Adaptive Transform Acoustic Coding (ATRAC, used in MiniDisc devices) FFmpeg (decoder only) ATSC/ETSI standards: Dolby Digital (AC3, ATSC A/52, ETSI TS 102 366) FFmpeg liba52 (decoder only) Dolby Digital Plus (E-AC-3, ATSC A/52:2012 Annex E, ETSI TS 102 366 Annex E) FFmpeg DTS Coherent Acoustics (DTS, Digital Theatre System Coherent Acoustics, ETSI TS 102 114) FFmpeg libdca (decoder only) Dolby AC-4 (ETSI TS 103 190) Impala Blackbird audio codec ITU standards: G.719 G.722 FFmpeg G.722.1 (subset of Siren7) and G.722.1 Annex C (subset of Siren14) libg722_1 libsiren (part of libmsn and msn-pecan) G.722.2 3GPP TS 26.173 AMR-WB speech Codec (C-source code) reference implementation opencore-amr (decoder) VisualOn AMR-WB encoder FFmpeg (decoding only) EVS MPEG-1 Audio and MPEG-2 Audio layer I (MP1) (MPEG-1, MPEG-2 and non-ISO MPEG-2.5) FFmpeg (decoder only) layer II (MP2) (MPEG-1, MPEG-2 and non-ISO MPEG-2.5) FFmpeg tooLame (encoding only) twoLame (encoding only) layer III (MP3) (MPEG-1, MPEG-2 and non-ISO MPEG-2.5) FFmpeg (decoding only) LAME (encoding only) Advanced Audio Coding (AAC) (MPEG-2 Part 7) FAAC (encoder) and FAAD (decoder) FFmpeg iTunes Nero AAC Codec VisualOn AAC Encoder (a.k.a. libvo_aacenc) Fraunhofer FDK AAC libaacplus MPEG-4 Audio Advanced Audio Coding (AAC, MPEG-4 Part 3 subpart 4), HE-AAC and AAC-LD FAAC, FAAD2 FFmpeg iTunes Nero AAC Codec MPEG-4 AAC reference software (ISO/IEC 14496-5:2001) Harmonic and Individual Lines and Noise (HILN, MPEG-4 Parametric Audio Coding) MPEG-4 reference software (ISO/IEC 14496-5:2001) TwinVQ MPEG-4 reference software (ISO/IEC 14496-5:2001) FFmpeg (decoding only) BSAC (Bit-Sliced Arithmetic Coding) MPEG-4 reference software (ISO/IEC 14496-5:2001) MPEG-H MPEG-H 3D Audio Musepack (a.k.a. MPEGplus) Musepack SV8 Tools FFmpeg (decoding only) NICAM AT&T Perceptual Audio Coder Precision Adaptive Subband Coding (PASC; a variant of MP1; used in Digital Compact Cassette) QDesign (purchased by DTS) QDesign Music Codec used in Apple QuickTime FFmpeg (decoding only) PictureTel (purchased by Polycom) Siren 7 libg722_1 libsiren (part of libmsn and msn-pecan) FFmpeg (decoder only) Siren 14 libg722_1 vgmstream (decoder only) Siren 22 NTT TwinVQ FFmpeg (decoder only) NTT TwinVQ Encoder, NTT TwinVQ