place.stream.media.defs

Lexicon Version: 1

Definitions

sourceTracks

Type: object

A collection of tracks representing the canonical source of a video.

Properties:

Name	Type	Req’d	Description	Constraints
tracks	Array of com.atproto.repo.strongRef	✅	The canonical list of tracks specifying the source of a video.

---

sourceClip

Type: object

An object representing that this video’s source is a clip from another video.

Properties:

Name	Type	Req’d	Description	Constraints
video	string	✅	AT URI of the video we’re clipping.	Format: at-uri
start	integer	✅	Start time of the clip in milliseconds.
end	integer	✅	End time of the clip in milliseconds.

---

muxlTrack

Type: object

A track backed by a MUXL container

Properties:

Name	Type	Req’d	Description	Constraints
blob	string	✅	BLAKE-3 content hash (BDASL CID) of the source video segment.
size	integer	❌	Size in bytes of the source video segment.
trackId	string	✅	ID of the track within the MUXL container. 1-indexed for MP4 reasons.
mediaType	string	✅	Type of the track: video, audio, or text.
language	string	❌	Language of the track, if applicable.
signingKey	string	❌	did:key of the ephemeral key that C2PA-signed this track’s segments. The private key is discarded once the track is produced, so it can only ever have signed this content.	Format: did

---

Lexicon Source

{
  "lexicon": 1,
  "id": "place.stream.media.defs",
  "defs": {
    "sourceTracks": {
      "type": "object",
      "description": "A collection of tracks representing the canonical source of a video.",
      "required": ["tracks"],
      "properties": {
        "tracks": {
          "type": "array",
          "description": "The canonical list of tracks specifying the source of a video.",
          "items": {
            "type": "ref",
            "ref": "com.atproto.repo.strongRef"
          }
        }
      }
    },
    "sourceClip": {
      "type": "object",
      "description": "An object representing that this video's source is a clip from another video.",
      "required": ["video", "start", "end"],
      "properties": {
        "video": {
          "type": "string",
          "format": "at-uri",
          "description": "AT URI of the video we're clipping."
        },
        "start": {
          "type": "integer",
          "description": "Start time of the clip in milliseconds."
        },
        "end": {
          "type": "integer",
          "description": "End time of the clip in milliseconds."
        }
      }
    },
    "muxlTrack": {
      "type": "object",
      "description": "A track backed by a MUXL container",
      "required": ["blob", "trackId", "mediaType"],
      "properties": {
        "blob": {
          "type": "string",
          "description": "BLAKE-3 content hash (BDASL CID) of the source video segment."
        },
        "size": {
          "type": "integer",
          "description": "Size in bytes of the source video segment."
        },
        "trackId": {
          "type": "string",
          "description": "ID of the track within the MUXL container. 1-indexed for MP4 reasons."
        },
        "mediaType": {
          "type": "string",
          "description": "Type of the track: video, audio, or text."
        },
        "language": {
          "type": "string",
          "description": "Language of the track, if applicable."
        },
        "signingKey": {
          "type": "string",
          "format": "did",
          "description": "did:key of the ephemeral key that C2PA-signed this track's segments. The private key is discarded once the track is produced, so it can only ever have signed this content."
        }
      }
    }
  }
}