1. What is Pixel Aspect Ratio?

Pixel Aspect Ratio (PAR) is the ratio of width to height of a single pixel in a digital image. It describes how pixels should be displayed to maintain proper proportions when the display aspect ratio differs from the storage aspect ratio.

2. How Does the Calculator Work?

The calculator uses the pixel aspect ratio formula:

Where:

• Display Aspect Ratio — The aspect ratio of the display device (e.g., 16:9 = 1.7778)
• Storage Aspect Ratio — The aspect ratio of the stored image (e.g., 4:3 = 1.3333)

Explanation: When PAR = 1, pixels are square. When PAR ≠ 1, pixels are rectangular (either wider or taller than they are square).

3. Importance of Pixel Aspect Ratio

Details: Correct PAR ensures images display with proper proportions. Incorrect PAR causes image distortion (stretching or squashing). This is particularly important in video production and digital imaging.

4. Using the Calculator

Tips: Enter both aspect ratios as decimal values (e.g., 16:9 = 1.7778, 4:3 = 1.3333). Both values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between PAR and display aspect ratio?
A: Display aspect ratio describes the screen shape, while PAR describes individual pixel shape needed to display content correctly.

Q2: When is PAR most important?
A: When working with standard definition video (like DV NTSC/PAL) or when converting between different aspect ratio standards.

Q3: What's a common example of non-square pixels?
A: NTSC DV (720x480) uses PAR of 0.9 (tall pixels) when displayed on 4:3, or 1.2 (wide pixels) when displayed on 16:9.

Q4: How does PAR affect image quality?
A: Incorrect PAR causes image distortion. Proper PAR maintains original proportions but may require resampling which can affect sharpness.

Q5: Are modern displays affected by PAR?
A: Most modern displays use square pixels (PAR = 1), but PAR remains important when working with legacy formats or certain professional video workflows.