Name | standardized by | description | bit rate (kb/s) | sampling rate (kHz) | frame size (ms) | remarks |
---|---|---|---|---|---|---|

(ADPCM) DVI | Intel, IMA | ADPCM | 32 | 8 | sample | |

G.711 | ITU-T | Pulse code modulation (PCM) | 64 | 8 | sample | mu-law (US, Japan) and A-law (Europe) companding |

G.721 | ITU-T | Adaptive differential pulse code modulation (ADPCM) | 32 | 8 | sample | Now described in G.726; obsolete. |

G.722 | ITU-T | 7 kHz audio-coding within 64 kbit/s | 64 | 16 | sample | Subband-codec that divides 16 kHz band into two subbands, each coded using ADPCM |

G.722.1 | ITU-T | Coding at 24 and 32 kbit/s for hands-free operation in systems with low frame loss | 24/32 | 16 | 20 | See also |

G.723 | ITU-T | Extensions of Recommendation G.721 adaptive differential pulse code modulation to 24 and 40 kbit/s for digital circuit multiplication equipment application | 24/40 | 8 | sample | Superceded by G.726; obsolete. This is a completely different codec than G.723.1. |

G.723.1 | ITU-T | Dual rate speech coder for multimedia communications transmitting at 5.3 and 6.3 kbit/s | 5.6/6.3 | 8 | 30 | Part of H.324 video conferencing. DSP Group. It encodes speech or other audio signals in frames using linear predictive analysis-by-synthesis coding. The excitation signal for the high rate coder is Multipulse Maximum Likelihood Quantization (MP-MLQ) and for the low rate coder is Algebraic-Code-Excited Linear-Prediction (ACELP). |

G.726 | ITU-T | 40, 32, 24, 16 kbit/s adaptive differential pulse code modulation (ADPCM) | 16/24/32/40 | 8 | sample | ADPCM; replaces G.721 and G.723. |

G.727 | ITU-T | 5-, 4-, 3- and 2-bit/sample embedded adaptive differential pulse code modulation (ADPCM) | var. | ? | sample | ADPCM. Related to G.726. |

G.728 | ITU-T | Coding of speech at 16 kbit/s using low-delay code excited linear prediction | 16 | 8 | CELP. Annex J offers variable-bit rate operation for DCME. | |

G.729 | ITU-T | Coding of speech at 8 kbit/s using conjugate-structure algebraic-code-excited linear-prediction (CS-ACELP) | 8 | 8 | 10 | Low delay (15 ms) |

GSM 06.10 | ETSI | RegularPulse Excitation LongTerm Predictor (RPE-LTP) | 13 | 8 | 22.5 | Used for GSM cellular telephony. |

LPC10e (FIPS 1015) | US Govt. | Linear-predictive codec | 2.4 | 8 | 22.5 | 10 coefficients. |

Last updated by Henning Schulzrinne