NIP-5E: Censorship Resistant Live Streams

5E.md

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+# NIP-5E
+
+## Censorship Resistant Live Streams
+
+`draft` `optional`
+
+Describes a way to distribute live video streams via nostr.
+
+**"Live Video" in this context implies segmented video streams like HLS or DASH**
+
+## N94 Stream
+
+A new `kind: 1053` event lists a single live stream.
+
+Example:
+
+```jsonc
+{
+  "kind": 1053,
+  "tags": [
+    ["title", "<name of the event>"],
+    ["summary", "<description>"],
+    ["image", "<preview image url>"],
+    [
+      "variant",
+      "dim 1920x1080",
+      "bitrate 5000000",
+      "m video/mp2t",
+      "d 1080p"
+    ],
+    [
+      "variant",
+      "dim 1280x720",
+      "bitrate 3000000",
+      "m video/mp2t",
+      "d 720p"
+    ],
+    [
+      "variant",
+      "dim 1920x1080",
+      "bitrate 6000000",
+      "m video/mp4",
+      "d 1080p-fmp4"
+    ],
+    ["t", "hashtag"]
+    ["starts", "<unix timestamp in seconds>"],
+    ["ends", "<unix timestamp in seconds>"],
+    ["relays", "wss://one.com", "wss://two.com", /*...*/],
+    ["pinned", "<event id of pinned live chat message>"],
+  ],
+  "content": "",
+  // other fields...
+}
+```
+
+The `variant` tag works like `imeta` tag from [NIP-92](92.md) and defines a variant stream.
+
+The `d` entry of the `variant` tag is used in the NIP-94 segment event for variant following.
+
+## N94 Segment
+
+Each segment of the stream is a [NIP-94](94.md) event which describes where the file can be found and its hash.
+
+```jsonc
+{
+  "kind": 1063,
+  "tags": [
+    ["d", "1080p"]
+    ["e", "<id-of-kind-1053>"],
+    ["x", "<sha256>"],
+    ["m", "video/mp2t"],
+    ["dim", "1920x1080"],
+    ["duration", "2.033"],
+    ["index", "1234"],
+    ["url", "https://example.com/1234.ts"],
+    ["fallback", "https://another.com/1234.ts"],
+    ["service", "blossom"],
+    ...
+  ]
+  // other fields...
+}
+```
+
+Aside from the standard NIP-94 tags:
+
+- `d`: Variant stream tag.
+- `index`: Segment index, a simple counter. Used of ordering.
+
+`service` tag should be used for extended censorship resitance by looking up the appropriate server list (Blossom) of the uploader and checking for files on alternate servers.
+
+## Implementors
+
+### Consumers
+
+Clients wishing to implement a player should use [MSE](https://developer.mozilla.org/en-US/docs/Web/API/Media_Source_Extensions_API) or similar technologies which allow appending data to the player buffer.
+
+Other services MAY provide a compatability layer with [NIP-53](53.md) live streams by producing HLS playlists over a N94 Stream.
+
+Clients SHOULD follow only a single variant by using a filter like this:
+
+`{"kinds":[1063],"#e":["<id-of-kind-5053>"],"#d":["1080p"],"limit":10}`
+
+Leaving the subscription open will allow clients to be notified immediately as segments are published and can fetch those segments and append them to the player buffer.
+
+### Producers
+
+Segment length SHOULD be carefully considered as a trade off between stream delay and total number of NIP-94 events / segment files.
+
+Using `expiration` tags on N94 segments and deleting segment files from servers SHOULD be used to cleanup streams which don't want to persist after the stream is finished.
+
+## Example implementations:
+
+### Player
+
+[zap.stream](https://github.com/v0l/zap.stream/blob/main/src/element/stream/n94-player.tsx)
+
+### Producer
+
+[zap-stream-core](https://github.com/v0l/zap-stream-core/blob/ccb2add6073e5bb68191c42613c34f66583e34fc/crates/zap-stream/src/overseer.rs#L340-L380)