{
  "id": "magic/ogg",
  "family": "magic",
  "slug": "ogg",
  "title": "Ogg signature (OggS)",
  "summary": "An Ogg container (carrying Vorbis, Opus, FLAC, Theora, etc.) begins each page with the 4-byte capture pattern 'OggS' (0x4F 0x67 0x67 0x53), followed by a stream-structure version byte (0x00).",
  "kind": "signature",
  "aliases": [
    "Ogg magic",
    "OggS",
    "capture pattern"
  ],
  "status": "standard",
  "verification": "verified",
  "tier": "B",
  "source_url": "https://www.rfc-editor.org/rfc/rfc3533#section-6",
  "source_version": "RFC 3533 (Ogg encapsulation format), Section 6 (capture_pattern 'OggS')",
  "retrieved_date": "2026-05-29",
  "see_also": [
    "magic/flac",
    "magic/matroska-webm"
  ],
  "ext_type": "file-signature@1",
  "ext": {
    "magic_hex": "4F 67 67 53",
    "offset": 0,
    "magic_ascii": "OggS",
    "extensions": [
      "ogg",
      "oga",
      "ogv",
      "opus",
      "spx"
    ],
    "mime": "application/ogg",
    "spec": "RFC 3533",
    "notes": [
      "'OggS' (4F 67 67 53) is the capture pattern at the start of every Ogg page, not just the file.",
      "The byte after the capture pattern is the stream structure version, currently 0x00.",
      "The codec inside is identified by the first packet of each logical stream (e.g. 'OpusHead', '\\x01vorbis', '\\x80theora')."
    ]
  },
  "updated": "2026-05-29T00:00:00Z"
}