Misconceptions of “High Definition” (Part 2)

15 02 2008

So continuing the “High Definition” misconceptions and some answers from my previous post. We’ll start off with an easy question that might have raised ??? in many consumers.

Question: What do you mean by the “p” and “i” in 1080p, 1080i, 720p, 480p, 480i?
The “p” stands for “progressive” scanning and “i” for “interlaced” scanning. Progressive scanning will scan the entire screen from top to bottom without skipping lines. Interlaced scanning will scan every other line from top to bottom thereby giving you only half the resolution but outputted at the same size. Hence, the blurriness you notice on 480i (aka Standard Definition) screens when comparing them with 480p (aka Enhanced Definition) screens.

What is “resolution” you say? The quality of the video in layman’s terms.

Question: Why are some HD channels clearer and sharper than others?
HD channels are required by default to have a minimum of 720 pixels vertically and in a wide-screen format. The average computer monitor is 1024 pixels wide by 768 pixels tall at a 4:3 format. HDTVs running at 720p resolutions are usually 1388 pixels wide and 720 pixels tall at 16:9 aspect ratio format.

Taking that into consideration, not all video are shot or processed into a widescreen format. So tv producers will take a standard definition broadcast video feed and stretch it to fit 720 pixels vertically but since it’s SD and not a HD broadcast, it will be in 4:3 ratio instead of 16:9. That will explain the borders on the sides of some of the tv shows you see on your HD TV used to fill up the broadcast.

When videos are stretched, the technical term used is “upscaling”. Upscaled high def broadcasts aren’t very clear because they were originally 480 pixels tall and are now stretch to nearly twice their size.

Question: Why can’t I change resolutions in HD channels?
HD channels are already programmed to fit your tv screen. Hence even if there are side borders on some shows, you are unable to stretch it cuz the side borders are included in the broadcast.

Question: Why are larger computer LCD monitors more expensive than equally sized HDTVs?
LCD computer monitors can output higher resolutions than HDTVs. They can easily pack in twice or more pixels than even the best High Def TV.

Question: Are high def TVs and wide-screen computer monitors aspect ratios different?
Yes. Wide-screen computer monitors are standardized at 16:10 ratio compared to HDTV’s 16:9. Not sure why but that’s just the industry agreement.

Finally we end with another question that bothers most people…

Question: Do we have to get satellite or cable to watch high definition channels?
NO. High definition channels are already available over the air with the more spendy tv antennas. Cable tv and satellite providers all have their own plans and rates for what shows you can see on HD but if you just want the basic stuff like ABC, NBC, CBS, and FOX, you can get em for free through your rabbit-ears and standard coax cables despite what people or “experts” say.

Cable and satellite tv providers will continue to give out standard definition (or sub-par) channels for now until competition mandates them all to bring out full HD channels.



One response

15 02 2008
Misconceptions of “High Definition” (Part 2)

[…] Read the rest of this great post here […]

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