Pixels -Reprise- by solidxsnake13224 via Flickr

When is a pixel not a pixel?

Like your TV, computer and movie screens, pixels have aspect ratios too. Not to be confused with picture aspect ratio, pixel aspect ratio deal with the shape of pixels. Early analog television was made of pixels that were square, but when the digital video standard was created, DV pixels are non-square. When the high definition standard was created, the standard was set back to square pixels. Confused yet?

All non-linear editing software can convert square pixels to non-square pixels and the other way as well. While video professionals (read: Chris) don’t have to think twice about this setting, it’s awfully confusing to those who aren’t as well versed with video editing (read: Rob).

So what is the difference? That’s what we’ll be discussing on this week’s show.

Resources:
Pixel Aspect Ratio Calculator – http://www.digitalrebellion.com/pixel_calc.htm
A Quick Guide to Digital Video Resolution and Aspect Ratio Conversions – http://lipas.uwasa.fi/~f76998/video/conversion
Artbeats’ Pixel Aspect Ratio, Part 1 – http://www.artbeats.com/articles/86

DSCN0593-c2b4s3 by 12fh

HD and HDV are both high definition video formats. Instead of playback formats, HD and HDV are recording formats. HD describes an image that is 1920×1080 or 1280×720 pixel images. HDV describes an image that uses rectangular pixels at a size of 1440×1080 that displays the same size as a 1920×1080 square pixel image (The pixels are 1.33 times wider than an HD pixel).

Bit rates vary between the two also, HDV has a bit rate of as high as half and as low as a quarter of an HD bit rate. Both formats use compression, but HDV uses interpolation and groups of pictures (gops) to create the necessary compression. HD also uses compression, but you have an option as to what kind of CoDec you want to use.