HTML5 Canvas

Hello 

I exported my Animation as a HTML5 Canvas into a MPEG-4. The Problem i have, is that the size of my imported sketch (Adobe Capture) does not fit into the specified size of the canvas. So only about a quarter of the animation i created is visible in the MPEG-4 File. The rest was cut off. 

Does anyone know why this happens and how i can change it?

Thank you!