What does "aspect ratio" describe in video?

Aspect ratio refers specifically to the relationship between the width and height of a video image, typically expressed as two numbers separated by a colon. For example, an aspect ratio of 16:9 indicates that for every 16 units of width, there are 9 units of height. This ratio is crucial because it determines how the image appears on screens, influencing the viewer's experience and the compatibility of the video with different display devices. Understanding aspect ratio is essential for content creators to ensure their videos play correctly on various platforms and devices, avoiding issues such as distortion or cropping.

The other aspects mentioned, such as frame rate, color depth, and resolution, refer to different characteristics of video but do not describe the aspect ratio. Frame rate pertains to the number of frames displayed per second, color depth relates to how many colors can be displayed, and resolution involves the overall clarity and detail of the image, represented by the number of pixels. Each of these elements plays a significant role in video production and playback but does not define the shape or proportional dimensions of the video image itself, which is the essence of aspect ratio.