When a video file is loaded to the player, the window fits its aspect automatically. However, you can manage the aspect ratio of the footage and the video image size according to your needs with the help of corresponding commands from the context menu – "Aspect" and "Zoom".

Aspect Ratio Changing

Right-click anywhere on the player screen and from the "Aspect" command choose whether you need 4:3, 16:9 aspect ratio or select "Default" to use the physical clip aspect ratio. The current aspect ratio value is marked:

Aspect context menu
If the selected aspect ratio value does not match the original aspect ratio of the clip, the image will be distorted.

Video Image Size Changing

To view the clip in original size, select 100% from the "Zoom" command in the context menu. The current zoom value is marked:

Zoom context menu