What Is Pixel Aspect Ratio?

Pixel Aspect Ratio (PAR) refers to the ratio of the width to the height of a single pixel in a digital image or display. It determines whether a pixel is square or rectangular. PAR is important for ensuring that images or videos are displayed correctly without distortion on different screens.

Formula:

Pixel Aspect Ratio = Pixel Width / Pixel Height

Types of Pixel Aspect Ratios:

1. Square Pixels (1:1)

• The width and height of the pixel are the same.
• Common in modern displays, TVs, and computer monitors (e.g., 1920×1080 or 4K resolutions).
• Ensures no distortion when displaying images or videos.

2. Rectangular Pixels (Not 1:1):

• The width and height of the pixel are different.
• Used in older formats like standard-definition TVs (SDTV) or certain video codecs.
• Example: The NTSC standard (used in North America) has a PAR of 0.91, where pixels are taller than they are wide.

Why It Matters:

If the Pixel Aspect Ratio doesn't match the display or video format, the image can look stretched or squished. To avoid this, PAR is often adjusted during video encoding or playback.

Example:

• A video with a resolution of 720×480 (not square pixels) might have a PAR of 0.91, meaning each pixel is slightly taller than it is wide.
• When played back on a modern display, the video player adjusts the image to appear correctly.

In short, Pixel Aspect Ratio ensures that digital images and videos look right, whether the pixels are square or rectangular!