For media items that are "motion photos", the Google Photos API allows you to append "=dv" to the base URL of a media item to get the item as a "video/mp4". Without the =dv, the item comes back as a "image/jpeg". This works more or less as described in the docs.
What I can't figure out is how to tell whether or not a given item is a motion photo. The metadata returned for motion photos looks to be the same as for regular photos. Is there something I'm missing or do I need to try loading each photo as a video and handling the 404s?
