May 312010

Another biggy in the questions department is HD.
(its all in the “i” and the “p”)

We hope that below explains (without getting too geeky or too long winded) what it is really and what you should watch out for.

HD referrers to a variety of differing resolutions all higher than SD.
HD has 2 main differences from SD – Resolution and frame rendering

A normal SD TV has one set resolution
Which is 720×576 lines or pixels shown at 25 frames per second. The frames are what is known as interlaced – meaning that 1 frame is actually made up of 2 frames lashed together in strips. All the even numbered horizontal lines mixed with odd numbered lines of the following frame. – Kind of like lacing your fingers together but not, as you would need only half the fingers on each hand.

You can watch a HD film on your computer as your screen’s resolution is high enough to cope with the increased information. Your ordinary TV cannot.

Sooner or later everyone will have a HD TV. However while HD TV and HD players should be able to show SD films (just). A film shot in SD can only be “up converted” to HD. Kind of like transferring your old VHS cassettes to DVD. It works but doesn’t look too great.
But films shot in HD can be “down converted” to be shown on an SD TV and looks absolutely stunning.

The two main (there really are way too many to mention) resolutions for HD are 1440×1080 and 1920×1080. We shoot the “documentary” and “television” packages in the former. For the “film” package and the “Diamond Lounge” we use the latter. All HD TVs and HD players can play these resolutions. Most HD movies are in 1440×1080 and most HD broadcast channels are in 1920×1080. So typically a decent new HD player will be playing at 1440×1080 and a decent HD TV can show a whole variety of HD formats including 1920×1080.

In conclusion

However, (other geekier settings) aside, the real nub of the matter is in how frames are rendered. You may often see an “i” in HD descriptions of wedding videography as in 1080i. This “i” is our old friend (and we mean old) interlaced frames. (half the fingers on each hand laced together).
The whole point of HD is that it mimics film. Film is not made of interlaced frames, but full individual frames. This is the main reason why it looks so nice as each frames is literal a still photo. In HD this is referred to as “p”. or progressive scan. Basically “i” is rubbish and “p” is great. While SD TV only plays “i” if your footage is shot in “i” you cannot change it to the far superior “p” later (when you get a lovely new HD TV). You have to “de-interlace” in edit which (and this is why “i” is so rubbish) literally makes up/invents the missing odd and even lines. Not good.

So regardless of all the flim flam that is spoken about HD and wedding videography. If you see an “i” remember that this old technology and “p” is the one of the main advantages HD has over SD.