Eventos de video

This specification defines video events representing a dedicated post of externally hosted content.

Unlike a kind:1 event with a video attached, video events are meant to contain all additional metadata concerning the subject media and to be surfaced in video-specific clients rather than general micro-blogging clients. The thought is for events of this kind to be referenced in a Netflix, YouTube, or TikTok like nostr client where the video itself is at the center of the experience.

Video Events

There are two types of video events represented by different kinds: normal and short video events. This is meant to allow clients to cater to each as the viewing experience for longer, mostly horizontal (landscape) videos is often different than that of short-form, mostly vertical (portrait), videos ("stories", "reels", "shorts" etc).

Nothing except cavaliership and common sense prevents a short video from being long, or a normal video from being vertical, and that may or may not be justified, it's mostly a stylistic qualitative difference, not a question of actual raw size.

Format

The format uses a regular event kind 21 for normal videos and 22 for short videos.

Addressable Video Events

For content that may need updates after publication (such as correcting metadata, descriptions, or handling URL migrations), addressable versions are available:

• Kind 34235 for addressable normal videos
• Kind 34236 for addressable short videos

These addressable events follow the same format as their regular counterparts but include a d tag as a unique identifier and can be updated while maintaining the same addressable reference. This is particularly useful for:

• Metadata corrections (descriptions, titles, tags) without republishing
• Preservation of imported content IDs from legacy platforms
• URL migration when hosting changes
• Platform migration tracking

The .content of these events is a summary or description on the video content.

The primary source of video information is the imeta tags which is defined in NIP-92

Each imeta tag can be used to specify a variant of the video by the dim & m properties, as well as multiple audio tracks (languages).

Clients should check if audio tracks are available and prefer them over in-video audio to allow smooth resolution switching without interrupting audio. The ov (original version) flags the original language track.

This NIP defines the following additional imeta properties aside from those listed in NIP-92 & NIP-94:

• duration (recommended) the duration of the video/audio in seconds (floating point number)
• bitrate (recommended) the average bitrate of the video/audio in bits/sec
• waveform (optional, audio only) amplitude values over time, space separated full integers, less than 100 values should be enough to render a nice visual

Example:

[
  ["imeta",
    "dim 1920x1080",
    "url https://myvideo.com/1080/12345.mp4",
    "x 3093509d1e0bc604ff60cb9286f4cd7c781553bc8991937befaacfdc28ec5cdc",
    "m video/mp4",
    "image https://myvideo.com/1080/12345.jpg",
    "image https://myotherserver.com/1080/12345.jpg",
    "fallback https://myotherserver.com/1080/12345.mp4",
    "fallback https://andanotherserver.com/1080/12345.mp4",
    "service nip96",
    "bitrate 3000000",
    "duration 29.223"
  ],
  ["imeta",
    "dim 1280x720",
    "url https://myvideo.com/720/12345.mp4",
    "x e1d4f808dae475ed32fb23ce52ef8ac82e3cc760702fca10d62d382d2da3697d",
    "m video/mp4",
    "image https://myvideo.com/720/12345.jpg",
    "image https://myotherserver.com/720/12345.jpg",
    "fallback https://myotherserver.com/720/12345.mp4",
    "fallback https://andanotherserver.com/720/12345.mp4",
    "service nip96",
    "bitrate 2000000",
    "duration 29.24"
  ],
  ["imeta",
    "dim 1280x720",
    "url https://myvideo.com/720/12345.m3u8",
    "x 704e720af2697f5d6a198ad377789d462054b6e8d790f8a3903afbc1e044014f",
    "m application/x-mpegURL",
    "image https://myvideo.com/720/12345.jpg",
    "image https://myotherserver.com/720/12345.jpg",
    "fallback https://myotherserver.com/720/12345.m3u8",
    "fallback https://andanotherserver.com/720/12345.m3u8",
    "service nip96",
    "duration 29.21"
  ],
  ["imeta",
    "url https://myaudio.com/audio/en/12345.mp3",
    "x b2e0a7a82ac9f3f3a71f1d9a78c381d5be9d1cf19dce258765c17c8a76287c93",
    "m audio/mp3",
    "waveform 0 7 35 8 100 100 49 8 4 16 8 10 7 2 20 10 100 100 100 100 100 100 15 100 100 100 25 60 5 4 3 1 0 100 100 15 100 29 88 0 33 11 39 100 100 19 4 100 42 35 5 0 1 5 0 0 11 38 100 94 17 11 44 58 5 100 100 100 55 14 72 100 100 57 6 1 14 2 16 100 100 40 16 100 100 6 32 14 13 41 36 16 14 6 3 0 1 2 1 6 0",
    "l en ISO-639-1 ov",
    "fallback https://myotherserver.com/audio/en/12345.mp3",
    "fallback https://andanotherserver.com/audio/en/12345.mp3",
    "service nip96",
    "bitrate  320000",
    "duration 29.24"
  ],
]

Where url is the primary server url and fallback are other servers hosting the same file, both url and fallback should be weighted equally and clients are recommended to use any of the provided video urls.

The image tag contains a preview image (at the same resolution). Multiple image tags may be used to specify fallback copies in the same way fallback is used for url.

Additionally service nip96 may be included to allow clients to search the authors NIP-96 server list to find the file using the hash.

Required tags for addressable events:

• d - Unique identifier for this video (user-chosen string, required for kinds 34235, 34236)

Other tags:

• title (required) title of the video
• published_at, for the timestamp in unix seconds (stringified) of the first time the video was published
• text-track (optional, repeated) link to WebVTT file for video, type of supplementary information (captions/subtitles/chapters/metadata), optional language code
• content-warning (optional) warning about content of NSFW video
• alt (optional) description for accessibility
• segment (optional, repeated) start timestamp in format HH:MM:SS.sss, end timestamp in format HH:MM:SS.sss, chapter/segment title, chapter thumbnail-url
• t (optional, repeated) hashtag to categorize video
• p (optional, repeated) 32-bytes hex pubkey of a participant in the video, optional recommended relay URL
• r (optional, repeated) references / links to web pages

Optional tags for imported content:

• origin - Track original platform and ID: ["origin", "<platform>", "<external-id>", "<original-url>", "<optional-metadata>"]

{
  "id": "<32-bytes lowercase hex-encoded SHA-256 of the the serialized event data>",
  "pubkey": "<32-bytes lowercase hex-encoded public key of the event creator>",
  "created_at": <Unix timestamp in seconds>,
  "kind": 21 | 22,
  "content": "<summary / description of video>",
  "tags": [
    ["title", "<title of video>"],
    ["published_at", "<unix timestamp>"],
    ["alt", "<description>"],

    // video Data
    ["imeta",
      "dim 1920x1080",
      "url https://myvideo.com/1080/12345.mp4",
      "x 3093509d1e0bc604ff60cb9286f4cd7c781553bc8991937befaacfdc28ec5cdc",
      "m video/mp4",
      "image https://myvideo.com/1080/12345.jpg",
      "image https://myotherserver.com/1080/12345.jpg",
      "fallback https://myotherserver.com/1080/12345.mp4",
      "fallback https://andanotherserver.com/1080/12345.mp4",
      "service nip96",
    ],

    ["text-track", "<encoded `kind 6000` event>", "<recommended relay urls>"],
    ["content-warning", "<reason>"],
    ["segment", <start>, <end>, "<title>", "<thumbnail URL>"],

    // participants
    ["p", "<32-bytes hex of a pubkey>", "<optional recommended relay URL>"],
    ["p", "<32-bytes hex of a pubkey>", "<optional recommended relay URL>"],

    // hashtags
    ["t", "<tag>"],
    ["t", "<tag>"],

    // reference links
    ["r", "<url>"],
    ["r", "<url>"]
  ]
}

Addressable Event Example

{
  "id": <32-bytes lowercase hex-encoded SHA-256 of the the serialized event data>,
  "pubkey": <32-bytes lowercase hex-encoded public key of the event creator>,
  "created_at": <Unix timestamp in seconds>,
  "kind": 34235 | 34236,
  "content": "<summary / description of video>",
  "tags": [
    ["d", "<unique-identifier>"],
    ["title", "<title of video>"],
    ["published_at", "<unix timestamp>"],
    ["alt", "<description for accessibility>"],

    // video data
    ["imeta",
      "url https://example.com/media.mp4",
      "m video/mp4",
      "dim 480x480",
      "blurhash eVF$^OI:${M{%LRjWBoLoLaeR*",
      "image https://example.com/thumb.jpg",
      "x 3093509d1e0bc604ff60cb9286f4cd7c781553bc8991937befaacfdc28ec5cdc"
    ],
    // audio data
    ["imeta",
      "url https://example.com/audio.mp3",
      "x b2e0a7a82ac9f3f3a71f1d9a78c381d5be9d1cf19dce258765c17c8a76287c93",
      "m audio/mp3",
      "l en ISO-639-1 ov"
    ],

    ["duration", <duration in seconds>],
    ["content-warning", "<reason>"],

    // origin tracking for imported content
    ["origin", "<platform>", "<external-id>", "<original-url>", "<optional-metadata>"],

    // participants
    ["p", "<32-bytes hex of a pubkey>", "<optional recommended relay URL>"],

    // hashtags
    ["t", "<tag>"],
    ["t", "<tag>"],

    // reference links
    ["r", "<url>"]
  ]
}

Referencing Addressable Events

To reference an addressable video:

["a", "34235:<pubkey>:<d-tag-value>", "<relay-url>"]  // for normal videos
["a", "34236:<pubkey>:<d-tag-value>", "<relay-url>"]  // for short videos