If you need to change the file Category there is a simple process for doing this
How to change the category of your files in Mediacentral
Each file resides in a particular category, to change this you will need to login to Mediacentral and access your content.
Use the drop down in the top right corner of the screen and click where you see a black silhouette

Click in My Content

This brings up a page showing all the files you have uploaded to Mediacentral, either through the Mediacentral website or though the Moodle Media Resource.

To change the category from your Personal listing, tick the box next to the file you wish to adjust or to select all tick the box at the top of the list.

Then use the drop-down list in the Category section to choose and change your files listed to a different category.
Then click Apply at the top of the media listing to move the clip to the chosen category.