Last night I sat down to watch the premiere of The Chopping Block on NBC and was surprised to see that my broadcast was being windowboxed on the screen.
What is windowboxing you ask? While I am watching this program on my 42" LCD HDTV, there is a thick black outline around the entire image, filling up half of my screen with dead space. This phenomenon is occurring more often recently as we shift into High Definition broadcasting.
The traditional tube television displays in an aspect ratio of 4:3 (for those of you not familiar with aspect ratios, that is the relationship between the length of the image and the height of the image). Brand new High Definition televisions now have a screen that is much wider than it is high, with an aspect ratio of 16:9. Just as the devices we use to watch programming have changed their aspect ratio, the cameras used to record the programs also have changed the shape of the images they capture.
So to get a 4:3 image to display without distortion on a 16:9 screen, the image is pillarboxed: the image is centered horizontally on the screen, and black space fills the left and right sides of the screen. Inversely, to view a 16:9 image on a 4:3 screen, the image is letterboxed: centered vertically, and black space fills the top and bottom.
So what I was seeing on my screen last night, was a program that was recorded in 16:9, but then was converted to be viewed on a 4:3 screen, which was then converted to fit my 16:9 screen. Dizzy yet?
Now this would make sense to me if I was watching a station that does not broadcast in HD, but this was not the case! The program before and after filled my screen with all of their HD glory! Apparently this revolution even confuses the "experts".
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1 comment:
Nice, I didn't know that! It has frustrated me to no end.
D. Cubano
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