Retrieving thumbnails using Video REST API
This post is a contribution from Vitaly Lyamin, an engineer with the SharePoint Developer Support team
The Video REST API provides an ability to discover and interact with videos. We’ve seen a number of issues retrieving thumbnails where the “ThumbnailURL” endpoint returns an endpoint (e.g. /pVid/video.mp4.PNG?VideoPreview=1) that is not suitable for use with an AAD app access token and is only accessible via cookie-based authentication (passive or active). Fortunately, there are a few solutions for this.
The Video REST API “ThumbnailStream” endpoint can be used with and without the width (in pixels) parameter.
The “GetPreview.ashx” handler can also be used with several different inputs (simple example below).
Resources https://blogs.msdn.microsoft.com/richard_dizeregas_blog/2014/09/15/developing-apps-against-the-office-graph-part-1/ https://blogs.msdn.microsoft.com/ocarpen/2015/01/09/office-graph-api-and-cortana-chapter-2-how-to-make-queries-by-code-to-the-office-graph/
Non-MS Resources: http://www.n8d.at/blog/image-renditions-available-in-modern-team-sites/ https://blog.beecomedigital.com/2015/07/27/generate-thumbnail-of-a-document-stored-in-sharepoint-from-its-url/