It's not possible to edit "ezmedia" fieldtype properties once it's published (without reuploading the video).

Steps to reproduce:
1. Login as admin
2. Go to Admin -> Content Types
3. Go to "Content" group
4. Create a new Content Type with "ezmedia" fieldtype
5. Publish it
6. Go to Content -> Content Structure
7. Create a item using created Content Type (you can use the video in the attachment)
8. Publish it
9. Edit
10. Set any fields: width, height, loop, controls etc.
11. Publish

Expected:
Set values are saved

Actual:
Set values are not saved.