You can define the width and height of the video in the View as Video settings.
The "Edit as" type for the View as Video can be either a Text field (enter video file name or URL there) or a File/Image (upload files).
Select The field contains Video file URL checkbox if the selected field stores the URL of the video file, for example, https://yourwebsite.com/folder/video.mp4.
Note: do not use this option if you use File/Image as the "Edit as" type for this field.
Select the Enable rewind/fast forward checkbox to enable additional controls in the resulting page.
An example of how video files appear in the browser:
See also:
•"Edit as" settings: Text field
•"Edit as" settings: File/Image