Aaspect ratio is a term that people make seem like it is more complicated than what really is it is only the comparison of how wider image is vs how tall . For example, if a graphic has an aspect ratio of 2:1, it means that the width is twice as large as the height When resizing graphics, it is important to maintain the aspect ratio to avoid stretching the graphic out of proportion.The term is also used to describe the dimensions of a display resolution. For example, a resolution of 800×600 has an aspect ratio of 4:3.or a resolution of 1080 x 1920 has an aspect ratio of 16:9 .
Widescreen Cinema Standard (2.35.1)
16:9 – Wide screen HD standard (1.78:1)
4:3 – SD sandard ( 1.33:1 )