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Recommended Media Attachment Format

The first three example are our recommendation on how to format image, video, and audio media attachments. Further properties are possible, and might make it into this recommendation at one point. Examples:

  • Focal point and blurhash, see Mastodon
  • fps (frames per second) for videos

The final example cannot be recommended yet as it is not widely supported. However, it illustrates how one can provide multiple versions of the media attachments. A high quality and low quality video in this case. The low quality video is enough for most use cases, and is 40 times smaller.

!!! info This recommendation is work in progress. A description of why these choices will hopefully appear as a FEP

Examples

Example 1

activity
{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    {
      "Hashtag": "as:Hashtag",
      "sensitive": "as:sensitive"
    }
  ],
  "type": "Create",
  "actor": "http://pasture-one-actor/actor",
  "to": [
    "https://www.w3.org/ns/activitystreams#Public",
    "http://mitra/users/admin"
  ],
  "id": "http://pasture-one-actor/actor/fPdRhv3XrdY",
  "published": "2025-02-07T20:56:33Z",
  "object": {
    "type": "Note",
    "attributedTo": "http://pasture-one-actor/actor",
    "to": [
      "https://www.w3.org/ns/activitystreams#Public",
      "http://mitra/users/admin"
    ],
    "id": "http://pasture-one-actor/actor/Ekt3gsmeeug",
    "published": "2025-02-07T20:56:33Z",
    "@context": [
      "https://www.w3.org/ns/activitystreams",
      "https://www.w3.org/ns/credentials/v2",
      {
        "size": "https://joinpeertube.org/ns#size"
      }
    ],
    "content": "Recommended Image Format",
    "attachment": [
      {
        "type": "Image",
        "name": "A beautiful cow",
        "url": "http://pasture-one-actor/assets/cow.jpg",
        "width": 100,
        "height": 162,
        "mediaType": "image/jpeg",
        "digestMultibase": "zQmaeDPzhNL32WQZnnzB1H6QJWvvFNEHdViDB71yrxyXU1t",
        "size": 9045
      }
    ]
  }
}
misskey
{
  "id": "a3yszc80pl2g000v",
  "createdAt": "2025-02-07T20:48:36.000Z",
  "userId": "a3ysz1b3pl2g0002",
  "user": {
    "id": "a3ysz1b3pl2g0002",
    "name": "Test Actor",
    "username": "actor",
    "host": "pasture-one-actor",
    "avatarUrl": "http://misskey/identicon/actor@pasture-one-actor",
    "avatarBlurhash": null,
    "avatarDecorations": [],
    "isBot": false,
    "isCat": false,
    "instance": {
      "name": null,
      "softwareName": null,
      "softwareVersion": null,
      "iconUrl": null,
      "faviconUrl": null,
      "themeColor": null
    },
    "emojis": {},
    "onlineStatus": "unknown"
  },
  "text": "Recommended Image Format",
  "cw": null,
  "visibility": "public",
  "localOnly": false,
  "reactionAcceptance": null,
  "renoteCount": 0,
  "repliesCount": 0,
  "reactionCount": 0,
  "reactions": {},
  "reactionEmojis": {},
  "emojis": {},
  "fileIds": [
    "a3yszctapl2g000u"
  ],
  "files": [
    {
      "id": "a3yszctapl2g000u",
      "createdAt": "2025-02-07T20:48:36.766Z",
      "name": "cow.jpg",
      "type": "image/jpeg",
      "md5": "79665fe8c07445157afebd1543f36b71",
      "size": 0,
      "isSensitive": false,
      "blurhash": "ejK^]TI9_3t6NG_4%gRkV[of%hWCIUt7jEo#V@aJbHofazadjYWVkD",
      "properties": {
        "width": 200,
        "height": 164
      },
      "url": "http://pasture-one-actor/assets/cow.jpg",
      "thumbnailUrl": "http://pasture-one-actor/assets/cow.jpg",
      "comment": "A beautiful cow",
      "folderId": null,
      "folder": null,
      "userId": "a3ysz1b3pl2g0002",
      "user": null
    }
  ],
  "replyId": null,
  "renoteId": null,
  "uri": "http://pasture-one-actor/actor/l0_zVHG5D6c",
  "clippedCount": 0
}
mitra
{
  "id": "0194e233-36ba-0cb7-e578-338cea23e16e",
  "uri": "http://pasture-one-actor/actor/Ekt3gsmeeug",
  "url": "http://pasture-one-actor/actor/Ekt3gsmeeug",
  "created_at": "2025-02-07T20:56:33Z",
  "edited_at": null,
  "account": {
    "id": "0194e232-b067-124b-0799-4ade30ddd9a9",
    "username": "actor",
    "acct": "actor@pasture-one-actor",
    "actor_id": "http://pasture-one-actor/actor",
    "url": "http://pasture-one-actor/actor",
    "display_name": "Test Actor",
    "created_at": "2025-02-07T20:56:00.359685Z",
    "note": "",
    "avatar": "http://mitra/api/v1/accounts/identicon?input=http://pasture-one-actor/actor",
    "header": "http://mitra/api/v1/accounts/identicon",
    "locked": false,
    "mention_policy": "none",
    "bot": false,
    "identity_proofs": [],
    "payment_options": [],
    "fields": [],
    "emojis": [],
    "followers_count": 0,
    "following_count": 0,
    "subscribers_count": 0,
    "statuses_count": 23,
    "source": null,
    "role": null,
    "authentication_methods": null,
    "client_config": null
  },
  "content": "Recommended Image Format",
  "in_reply_to_id": null,
  "in_reply_to_account_id": null,
  "reblog": null,
  "visibility": "public",
  "sensitive": false,
  "spoiler_text": "",
  "pinned": false,
  "replies_count": 0,
  "favourites_count": 0,
  "reblogs_count": 0,
  "poll": null,
  "media_attachments": [
    {
      "id": "0194e233-36b6-9d67-2832-7f0ab7e178a9",
      "type": "image",
      "url": "http://mitra/media/6e403ee33c2817a06af46b6e362c054aec3b43057ff32d2f7ac7761761e6e1ff.jpg",
      "preview_url": "http://mitra/media/6e403ee33c2817a06af46b6e362c054aec3b43057ff32d2f7ac7761761e6e1ff.jpg",
      "description": "A beautiful cow"
    }
  ],
  "mentions": [
    {
      "id": "0194e231-607b-c1e5-c5c3-2ce84c557b8b",
      "username": "admin",
      "acct": "admin",
      "url": "http://mitra/users/admin"
    }
  ],
  "tags": [],
  "emojis": [],
  "favourited": false,
  "reblogged": false,
  "bookmarked": false,
  "pleroma": {
    "emoji_reactions": [],
    "in_reply_to_account_acct": null,
    "parent_visible": true,
    "quote": null,
    "quote_visible": false
  },
  "ipfs_cid": null,
  "links": []
}

Example 2

activity
{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    {
      "Hashtag": "as:Hashtag",
      "sensitive": "as:sensitive"
    }
  ],
  "type": "Create",
  "actor": "http://pasture-one-actor/actor",
  "to": [
    "https://www.w3.org/ns/activitystreams#Public",
    "http://mitra/users/admin"
  ],
  "id": "http://pasture-one-actor/actor/bEGMhCgzvpc",
  "published": "2025-02-07T20:56:34Z",
  "object": {
    "type": "Note",
    "attributedTo": "http://pasture-one-actor/actor",
    "to": [
      "https://www.w3.org/ns/activitystreams#Public",
      "http://mitra/users/admin"
    ],
    "id": "http://pasture-one-actor/actor/wJKjyjAKhUo",
    "published": "2025-02-07T20:56:34Z",
    "@context": [
      "https://www.w3.org/ns/activitystreams",
      "https://www.w3.org/ns/credentials/v2",
      {
        "size": "https://joinpeertube.org/ns#size"
      }
    ],
    "content": "Recommended Video Attachment",
    "attachment": [
      {
        "type": "Video",
        "url": "http://pasture-one-actor/assets/cow_eating.mp4",
        "name": "A beautiful cow eating",
        "width": 256,
        "height": 144,
        "mediaType": "video/mp4",
        "digestMultibase": "zQmSzK5qEe5tpjwGMhmjx9RvVoPkWhEmCwxP2s7wPMpKMoK",
        "size": 54373,
        "duration": "PT3S"
      }
    ]
  }
}
misskey
{
  "id": "a3yszczspl2g000x",
  "createdAt": "2025-02-07T20:48:37.000Z",
  "userId": "a3ysz1b3pl2g0002",
  "user": {
    "id": "a3ysz1b3pl2g0002",
    "name": "Test Actor",
    "username": "actor",
    "host": "pasture-one-actor",
    "avatarUrl": "http://misskey/identicon/actor@pasture-one-actor",
    "avatarBlurhash": null,
    "avatarDecorations": [],
    "isBot": false,
    "isCat": false,
    "instance": {
      "name": null,
      "softwareName": null,
      "softwareVersion": null,
      "iconUrl": null,
      "faviconUrl": null,
      "themeColor": null
    },
    "emojis": {},
    "onlineStatus": "unknown"
  },
  "text": "Recommended Video Attachment",
  "cw": null,
  "visibility": "public",
  "localOnly": false,
  "reactionAcceptance": null,
  "renoteCount": 0,
  "repliesCount": 0,
  "reactionCount": 0,
  "reactions": {},
  "reactionEmojis": {},
  "emojis": {},
  "fileIds": [
    "a3yszdiopl2g000w"
  ],
  "files": [
    {
      "id": "a3yszdiopl2g000w",
      "createdAt": "2025-02-07T20:48:37.680Z",
      "name": "cow_eating.mp4",
      "type": "video/mp4",
      "md5": "19e0d3ecdd0230ed857c9c88dd247012",
      "size": 0,
      "isSensitive": false,
      "blurhash": null,
      "properties": {},
      "url": "http://pasture-one-actor/assets/cow_eating.mp4",
      "thumbnailUrl": null,
      "comment": "A beautiful cow eating",
      "folderId": null,
      "folder": null,
      "userId": "a3ysz1b3pl2g0002",
      "user": null
    }
  ],
  "replyId": null,
  "renoteId": null,
  "uri": "http://pasture-one-actor/actor/r7tSgjZ44Ug",
  "clippedCount": 0
}
mitra
{
  "id": "0194e233-3cb9-aa29-e0f3-7046d097e355",
  "uri": "http://pasture-one-actor/actor/wJKjyjAKhUo",
  "url": "http://pasture-one-actor/actor/wJKjyjAKhUo",
  "created_at": "2025-02-07T20:56:34Z",
  "edited_at": null,
  "account": {
    "id": "0194e232-b067-124b-0799-4ade30ddd9a9",
    "username": "actor",
    "acct": "actor@pasture-one-actor",
    "actor_id": "http://pasture-one-actor/actor",
    "url": "http://pasture-one-actor/actor",
    "display_name": "Test Actor",
    "created_at": "2025-02-07T20:56:00.359685Z",
    "note": "",
    "avatar": "http://mitra/api/v1/accounts/identicon?input=http://pasture-one-actor/actor",
    "header": "http://mitra/api/v1/accounts/identicon",
    "locked": false,
    "mention_policy": "none",
    "bot": false,
    "identity_proofs": [],
    "payment_options": [],
    "fields": [],
    "emojis": [],
    "followers_count": 0,
    "following_count": 0,
    "subscribers_count": 0,
    "statuses_count": 24,
    "source": null,
    "role": null,
    "authentication_methods": null,
    "client_config": null
  },
  "content": "Recommended Video Attachment",
  "in_reply_to_id": null,
  "in_reply_to_account_id": null,
  "reblog": null,
  "visibility": "public",
  "sensitive": false,
  "spoiler_text": "",
  "pinned": false,
  "replies_count": 0,
  "favourites_count": 0,
  "reblogs_count": 0,
  "poll": null,
  "media_attachments": [
    {
      "id": "0194e233-3cb4-16b8-8681-30a68418db8c",
      "type": "video",
      "url": "http://mitra/media/4514a0bf67069eb36444ace0c4d5d6d4b95be4f01490e6a22ada67bbc3967d0e.mp4",
      "preview_url": "http://mitra/media/4514a0bf67069eb36444ace0c4d5d6d4b95be4f01490e6a22ada67bbc3967d0e.mp4",
      "description": "A beautiful cow eating"
    }
  ],
  "mentions": [
    {
      "id": "0194e231-607b-c1e5-c5c3-2ce84c557b8b",
      "username": "admin",
      "acct": "admin",
      "url": "http://mitra/users/admin"
    }
  ],
  "tags": [],
  "emojis": [],
  "favourited": false,
  "reblogged": false,
  "bookmarked": false,
  "pleroma": {
    "emoji_reactions": [],
    "in_reply_to_account_acct": null,
    "parent_visible": true,
    "quote": null,
    "quote_visible": false
  },
  "ipfs_cid": null,
  "links": []
}

Example 3

activity
{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    {
      "Hashtag": "as:Hashtag",
      "sensitive": "as:sensitive"
    }
  ],
  "type": "Create",
  "actor": "http://pasture-one-actor/actor",
  "to": [
    "https://www.w3.org/ns/activitystreams#Public",
    "http://mitra/users/admin"
  ],
  "id": "http://pasture-one-actor/actor/E_a3b8Gdsl0",
  "published": "2025-02-07T20:56:36Z",
  "object": {
    "type": "Note",
    "attributedTo": "http://pasture-one-actor/actor",
    "to": [
      "https://www.w3.org/ns/activitystreams#Public",
      "http://mitra/users/admin"
    ],
    "id": "http://pasture-one-actor/actor/o8QCEUdKwzU",
    "published": "2025-02-07T20:56:36Z",
    "@context": [
      "https://www.w3.org/ns/activitystreams",
      "https://www.w3.org/ns/credentials/v2",
      {
        "size": "https://joinpeertube.org/ns#size"
      }
    ],
    "content": "Recommended Audio Format",
    "attachment": [
      {
        "type": "Audio",
        "url": "http://pasture-one-actor/assets/cow_moo.mp3",
        "name": "A cow mooing",
        "mediaType": "audio/mpeg",
        "digestMultibase": "zQmSXTyLCPqoiGoUUwKRMKgFdddaAUkvQNr29nhB6tahb9Z",
        "size": 67709,
        "duration": "PT2.1S"
      }
    ]
  }
}
misskey
{
  "id": "a3yszczspl2g000z",
  "createdAt": "2025-02-07T20:48:37.000Z",
  "userId": "a3ysz1b3pl2g0002",
  "user": {
    "id": "a3ysz1b3pl2g0002",
    "name": "Test Actor",
    "username": "actor",
    "host": "pasture-one-actor",
    "avatarUrl": "http://misskey/identicon/actor@pasture-one-actor",
    "avatarBlurhash": null,
    "avatarDecorations": [],
    "isBot": false,
    "isCat": false,
    "instance": {
      "name": null,
      "softwareName": null,
      "softwareVersion": null,
      "iconUrl": null,
      "faviconUrl": null,
      "themeColor": null
    },
    "emojis": {},
    "onlineStatus": "unknown"
  },
  "text": "Recommended Audio Format",
  "cw": null,
  "visibility": "public",
  "localOnly": false,
  "reactionAcceptance": null,
  "renoteCount": 0,
  "repliesCount": 0,
  "reactionCount": 0,
  "reactions": {},
  "reactionEmojis": {},
  "emojis": {},
  "fileIds": [
    "a3yszdrupl2g000y"
  ],
  "files": [
    {
      "id": "a3yszdrupl2g000y",
      "createdAt": "2025-02-07T20:48:38.010Z",
      "name": "cow_moo.mp3",
      "type": "audio/mpeg",
      "md5": "af0b1c1fdd1e74cb559072d725f7de31",
      "size": 0,
      "isSensitive": false,
      "blurhash": null,
      "properties": {},
      "url": "http://pasture-one-actor/assets/cow_moo.mp3",
      "thumbnailUrl": null,
      "comment": "A cow mooing",
      "folderId": null,
      "folder": null,
      "userId": "a3ysz1b3pl2g0002",
      "user": null
    }
  ],
  "replyId": null,
  "renoteId": null,
  "uri": "http://pasture-one-actor/actor/X_qiCsfw6qo",
  "clippedCount": 0
}
mitra
{
  "id": "0194e233-4295-13e1-2634-8b2b6c0e6bbf",
  "uri": "http://pasture-one-actor/actor/o8QCEUdKwzU",
  "url": "http://pasture-one-actor/actor/o8QCEUdKwzU",
  "created_at": "2025-02-07T20:56:36Z",
  "edited_at": null,
  "account": {
    "id": "0194e232-b067-124b-0799-4ade30ddd9a9",
    "username": "actor",
    "acct": "actor@pasture-one-actor",
    "actor_id": "http://pasture-one-actor/actor",
    "url": "http://pasture-one-actor/actor",
    "display_name": "Test Actor",
    "created_at": "2025-02-07T20:56:00.359685Z",
    "note": "",
    "avatar": "http://mitra/api/v1/accounts/identicon?input=http://pasture-one-actor/actor",
    "header": "http://mitra/api/v1/accounts/identicon",
    "locked": false,
    "mention_policy": "none",
    "bot": false,
    "identity_proofs": [],
    "payment_options": [],
    "fields": [],
    "emojis": [],
    "followers_count": 0,
    "following_count": 0,
    "subscribers_count": 0,
    "statuses_count": 25,
    "source": null,
    "role": null,
    "authentication_methods": null,
    "client_config": null
  },
  "content": "Recommended Audio Format",
  "in_reply_to_id": null,
  "in_reply_to_account_id": null,
  "reblog": null,
  "visibility": "public",
  "sensitive": false,
  "spoiler_text": "",
  "pinned": false,
  "replies_count": 0,
  "favourites_count": 0,
  "reblogs_count": 0,
  "poll": null,
  "media_attachments": [
    {
      "id": "0194e233-4291-1272-78a9-e4c89e65e583",
      "type": "audio",
      "url": "http://mitra/media/3e33fee4c40cdc62e2744d8cf9b7b65b97e0af17e81170b067a1b8fe49b88f28.m2a",
      "preview_url": "http://mitra/media/3e33fee4c40cdc62e2744d8cf9b7b65b97e0af17e81170b067a1b8fe49b88f28.m2a",
      "description": "A cow mooing"
    }
  ],
  "mentions": [
    {
      "id": "0194e231-607b-c1e5-c5c3-2ce84c557b8b",
      "username": "admin",
      "acct": "admin",
      "url": "http://mitra/users/admin"
    }
  ],
  "tags": [],
  "emojis": [],
  "favourited": false,
  "reblogged": false,
  "bookmarked": false,
  "pleroma": {
    "emoji_reactions": [],
    "in_reply_to_account_acct": null,
    "parent_visible": true,
    "quote": null,
    "quote_visible": false
  },
  "ipfs_cid": null,
  "links": []
}

Example 4

activity
{
  "@context": [
    "https://www.w3.org/ns/activitystreams",
    {
      "Hashtag": "as:Hashtag",
      "sensitive": "as:sensitive"
    }
  ],
  "type": "Create",
  "actor": "http://pasture-one-actor/actor",
  "to": [
    "https://www.w3.org/ns/activitystreams#Public",
    "http://mitra/users/admin"
  ],
  "id": "http://pasture-one-actor/actor/sU-aPz7U0I8",
  "published": "2025-02-07T20:56:38Z",
  "object": {
    "type": "Note",
    "attributedTo": "http://pasture-one-actor/actor",
    "to": [
      "https://www.w3.org/ns/activitystreams#Public",
      "http://mitra/users/admin"
    ],
    "id": "http://pasture-one-actor/actor/9JXHjt1fSV0",
    "published": "2025-02-07T20:56:38Z",
    "@context": [
      "https://www.w3.org/ns/activitystreams",
      "https://www.w3.org/ns/credentials/v2",
      {
        "size": "https://joinpeertube.org/ns#size"
      }
    ],
    "content": "Multiple formats for video",
    "attachment": [
      {
        "type": "Video",
        "name": "A beautiful cow eating",
        "url": [
          {
            "type": "Link",
            "size": 54373,
            "digest": "zQmSzK5qEe5tpjwGMhmjx9RvVoPkWhEmCwxP2s7wPMpKMoK",
            "width": 256,
            "height": 144,
            "href": "http://pasture-one-actor/assets/cow_eating.mp4",
            "mediaType": "video/mp4"
          },
          {
            "type": "Link",
            "size": 2271723,
            "digest": "zQme2X4rgWuRdmAtGGMSEbdoeRQ2NAL2VptcdRGTYDZbSKG",
            "width": 1920,
            "height": 1080,
            "href": "http://pasture-one-actor/assets/cow_eating_hd.mp4",
            "mediaType": "video/mp4"
          }
        ],
        "duration": "PT3S"
      }
    ]
  }
}
misskey
{
  "id": "a3yszdrkpl2g0010",
  "createdAt": "2025-02-07T20:48:38.000Z",
  "userId": "a3ysz1b3pl2g0002",
  "user": {
    "id": "a3ysz1b3pl2g0002",
    "name": "Test Actor",
    "username": "actor",
    "host": "pasture-one-actor",
    "avatarUrl": "http://misskey/identicon/actor@pasture-one-actor",
    "avatarBlurhash": null,
    "avatarDecorations": [],
    "isBot": false,
    "isCat": false,
    "instance": {
      "name": null,
      "softwareName": null,
      "softwareVersion": null,
      "iconUrl": null,
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