{ "$schema": "https://json-schema.org/draft/2020-12/schema",
  "$id":     "https://schemas.mpai.community/TFA/V1.5/formats/SpeechContentFormats.json",
  "title":   "SpeechContentFormats",
  "type":    "string", "oneOf": [
    { "const": "G711A",
      "description": "ITU‑T G.711 A‑law: 8 kHz, 8‑bit logarithmic PCM companding at 64 kbit/s; widely used in telephony outside North America/Japan." },
    { "const": "G711mu",
      "description": "ITU‑T G.711 μ‑law: 8 kHz, 8‑bit logarithmic PCM companding at 64 kbit/s; commonly used in North America and Japan." },
    { "const": "MP3",
      "description": "MPEG‑1/2 Layer III perceptual audio codec; frequently used to distribute speech at low to medium bitrates." },
    { "const": "AAC",
      "description": "Advanced Audio Coding (MPEG‑4/2 AAC); higher efficiency than MP3 for speech and general audio at comparable bitrates." },
    { "const": "G722",
      "description": "ITU‑T wideband speech codec (16 kHz sampling, 64/56/48 kbit/s) used for HD‑Voice in telephony." },
    { "const": "G7231",
      "description": "ITU‑T low‑bitrate VoIP codec (5.3/6.3 kbit/s) based on CELP/MP‑MLQ, narrowband 8 kHz sampling." },
    { "const": "G726",
      "description": "ITU‑T ADPCM speech codec (16/24/32/40 kbit/s) used in legacy telephony and embedded systems." },
    { "const": "G729",
      "description": "ITU‑T CS‑ACELP narrowband speech codec at 8 kbit/s; widely deployed in VoIP; Annex B adds VAD/CNG." },
    { "const": "GSM-FR",
      "description": "GSM Full‑Rate narrowband codec (~13 kb/s) used in early GSM networks." },
    { "const": "GSM-EFR",
      "description": "GSM Enhanced Full‑Rate (12.2 kb/s) improved speech quality over GSM‑FR in 2G networks." },
    { "const": "GSM-HR", 
      "description": "GSM Half‑Rate (~5.6 kb/s) for increased capacity with lower bitrates." },
    { "const": "AMR",
      "description": "Adaptive Multi‑Rate (NB) 3GPP codec (4.75–12.2 kb/s, 8 kHz) for mobile voice with mode adaptation and VAD/CNG." },
    { "const": "AMR-WB",
      "description": "Adaptive Multi‑Rate Wideband (G.722.2) 3GPP/ITU codec (6.6–23.85 kb/s, 16 kHz) for HD‑voice in 3G/4G." },
    { "const": "iLBC",
      "description": "Internet Low Bitrate Codec (13.33/15.2 kb/s, 8 kHz) robust to packet loss in VoIP." },
    { "const": "Speex",
      "description": "Open‑source CELP speech codec (NB/WB modes) designed for VoIP; supports VAD/DTX/PLC." },
    { "const": "Opus",
      "description": "IETF full‑band speech/audio codec (8–48 kHz, wide bitrate range) used in WebRTC; supports NB→FB, low delay, VBR/CBR." },
    { "const": "EVS",
      "description": "3GPP Enhanced Voice Services for VoLTE/5G, supporting NB/WB/SWB/FB with high robustness and quality." },
    { "const": "SILK",
      "description": "Skype/3rd‑party ultra‑wideband speech codec (basis for Opus’ speech layer) optimized for conversational voice." },
    { "const": "iSAC",
      "description": "Internet Speech Audio Codec (wideband) used in WebRTC for low‑delay, adaptive bitrate speech." } ] }