Upload a file to use in <<media::alias>> Script annotation.

This endpoint returns mediaId that is the reference to the file and the upload URL. In order to upload your file, make a PUT request to the returned URL, with your file as payload.

Think of the alias part of <<media::alias>> annotation as the reference to the placeholder in the Script. You link this placeholder to the actual file by using mediaFiles field in POST /mastering request, e.g. mediaFiles={"alias": "f22e7250"}