NIP-71
======

Video Events
------------

`draft` `optional`

This specification defines video events representing a dedicated post of externally hosted content. These video events are _addressable_ and delete-requestable per [NIP-09](09.md).

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: horizontal and vertical video events. This is meant to allow clients to cater to each as the viewing experience for horizontal (landscape) videos is often different than that of vertical (portrait) videos (Stories, Reels, Shorts, etc).

#### Format

The format uses an _addressable event_ kind `34235` for horizontal videos and `34236` for vertical videos.

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](92.md)

Each `imeta` tag can be used to specify a variant of the video by the `dim` & `m` properties.

Example:
```json
[
  ["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",
  ],
  ["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",
  ],
  ["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",
  ],
]
```

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.

### 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
* `duration` (optional) video duration in seconds
* `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

```jsonc
{
  "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", "<UUID>"],

    ["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",
    ],

    ["duration", <duration of video in seconds>],
    ["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>"]
  ]
}
```