Video.mimes

The media file MIME types the player can play, such as video/mp4 or video/webm. It has been required in every version from 2.0 to 2.6 and is the only required field on the object today.

Currentstring arrayRequiredSince 2.0

Field facts

Path: imp.video.mimes
Object: Video
Type: string array
Requirement: Required
Added: OpenRTB 2.0
Spec section: 3.2.7

How it is used

Buyers match this list against the type attribute of each MediaFile in their VAST creatives. List what the player decodes on this device, not everything your ad server could transcode. With server-side stitching, list what the stitcher ingests. Including application/javascript tells buyers the player can run VPAID JavaScript, so leave it out where the player cannot.

Example

Where the field sits in a payload, with everything else left out:

{
  "id": "req-1",
  "imp": [
    {
      "video": {
        "mimes": [
          "video/mp4",
          "video/webm"
        ]
      }
    }
  ]
}

Common mistakes

Sending an empty array. It passes a naive presence check but offers no playable format, so no creative can match.
Sending a bare extension such as "mp4" instead of a full MIME type such as "video/mp4", which defeats exact string matching.
Sending a single string instead of an array, which is an openrtb.type.mismatch.

Version history

Added in OpenRTB 2.0, and present in the latest snapshot. The table shows how each version's spec text types the field.

Versions	Type in the spec	Required	Deprecated
2.0	array of string, default - wmv” “vide	Yes	No
2.1	array of string	Yes	No
2.2	array of strings	Yes	No
2.3 to 2.4	string array	Yes	No
2.5 to 2.6-202606	string array	Yes	No