Pixelförhållande

Pixelförhållande, or pixel aspect ratio, refers to the ratio of a pixel's width to its height. In digital imaging, pixels are often treated as square by default, meaning their width and height are equal. However, in some older video formats and displays, pixels were not square. For example, in standard definition (SD) video, pixels might have been rectangular, being wider than they were tall.

When displaying images or video with non-square pixels on a square-pixel display, the image can appear distorted. If the pixels are wider than they are tall, the image will look horizontally stretched. Conversely, if the pixels are taller than they are wide, the image will appear vertically stretched.

To correct for these distortions, display devices or software use the pixel aspect ratio information associated with the video signal. This information tells the display how to interpret the shape of each pixel. By adjusting the display's scaling or sampling, the image can be rendered with the correct proportions, appearing natural and undistorted. Modern digital video formats, such as high definition (HD) and 4K, predominantly use square pixels, simplifying display processing. However, understanding pixel aspect ratio remains important for compatibility with older media or specific broadcast standards.