Media (video) attributes like width/height are not properly saved during content creation.
When content is uploaded (but not yet published), then in preview the mentioned properties are set correctly. After publish, there are no width/height values. In edit view of this content, you can see that width and height are set to 0.
If you manually change values in the edit mode and publish content, then values will be correctly saved.

Steps to reproduce
1. Create ContentType with Media field, for e.g. Video
2. Create content of type Video, select some file
3. You can see, that in preview video width and height are set correctly
4. Publish content
5. Go to the content preview, there is lack of these parameters
6. Edit content -> you can see, that these parameters have default (0) values
7. Edit values and publish
8. Go to the preview -> you can see, those manually set parameters were saved correctly

More information
I did some test, and I see that during new content publishing, PlatformUI sends to the REST width and height values equal 0, although these values are correct in the preview.

Open question
After the additional test, I realized that in video preview (before content was published) values which are visible in width and height fields are empty, and we see only placeholders. I think that it might be really confusing for the customer. sylvain.guittard@ez.no what do you think? How should it be solved?