The MediaID refers to the 8 digit number that corresponds with the entire encoding request that you have made to the platform. This applies for the API, watch folder and single Add Media actions. If you were to submit an encoding request / query that contains several formats, each of those formats is issued a TaskID. It's very important to note the difference between the two. Via our Support portal, you will be asked to provide the MediaID so that we can troubleshoot the entire request, even though one TaskID has failed.