OK, so your video editor comes to your desk and says that the video clip you wanted is ”320 x 240,” . . . and you basically rely on the look on his or her face as to whether that is a good thing or bad thing.  Sound familiar?

Let’s see if we can’t help you look a little less like a deer in the headlights in such situations.

Again, my disclaimer, I myself have had my deer-in-the-headlight moments, and I am not a bonafide engineer (I only play one on TV - ok, ok, I couldn’t resist), but over my years as a producer, director and editor, I picked up info along the way — at least enough to help me survive. (though some might say I know just enough to be dangerous, but let’s ignore that, ok?)

With that all said, let’s move on to the topic at hand.  Video Resolution: it all comes down to pixels.

Those are the dots, with color components in them, that get energized by an electric charge to create a certain brightness and color.   And seen together, all those pixels make up an image.

And the denser the arrangement of pixels, the higher resolution the resulting picture is.

A standard definition television screen is made up of 525 horizontal lines and 720 columns of pixels.  Do the math and you get a conceivable 378,000 pixels.  

In reality, only 480 of the 525 video horizontal lines in SD are actually used for the picture.  The other 55 lines are not seen on regular screens.  They make up what’s called the “vertical interval” where such info as closed captioning, Sigma and SpoTTrac-ing info (see my blog on those:  http://tinyurl.com/65c2hp ) and vertical interval time code are carried.

So, the resolution for a regular standard def full screen tv picture is usually stated as 720 x 480 (with the 480 actually alternating scanning of even and odd 240 lines — see my blog about 24P that includes info about the differences between progressive and interlaced: http://tinyurl.com/57eghk )

And yes, even those 720 columns sometimes get cut down to 680 through other electronic shenanigans.  Oy vey.  What’s a viewer to do?

Now you know what drives the movement to HD.

High Defitinition resolution ranges from 1,980 columns of pixels and 1080 horizontal lines (scanned interlaced) — to 1,280 columns of pixels with 720 progressively scanned lines.   Do the math for either, and you’re looking between 921,600 to 2,138,400 available pixels. 

Higher Definition does indeed mean higher resolution.

Now, there are “super-duper” HD formats that are used by high-end moviemakers.  You’ll hear the terms 2K and 4K associated with those.   Check out this link to a popular high-end HD camera, The Red Digital Camera. http://www.red.com/ 

What’s going on is that these higher-end HD cameras are increasing both the number of columns and lines of pixels in a frame — part of the on-going quest to get digital filmmaking to match 35mm filmmaking.

Chris Vazquez (of “Ask Chris” on this site http://tinyurl.com/9l9xre ) sent me an article about where a 4K projector is being used http://www.vrac.iastate.edu/c6.php and its increasing popularity.

So let’s go back to my original statement, where the editor tells you the image is 320 x 240.  What’s going on with that?  This takes us the opposite way.   Think now . . .  yes, that’s like half the size of a regular standard def picture.  Hmmm, what could be like that?  And then you remember the term  ”compressed video” . . . video that can be played on a CD rather than a DVD, where the image doesn’t fill the whole screen. 

Yes, what the editor is telling you is that the video clip is not intended for full-screen video.  It’s set up to be played off a CD, or in a standard PowerPoint presentation, or perhaps on a website.

This topic can get much more detailed, and I invite you to check out http://en.wikipedia.org/wiki/Pixel and http://en.wikipedia.org/wiki/Display_resolution, but I hope I have given you some initial grasp of the world of video resolution. 

I welcome your comments below.  And feel free to contact me at dryan@videolabs.net or 301-217-0000 x104 with any questions.

If you found this article of interest, you may want to also check out Chris Vazquez’ article about “anamorphic” images.  http://tinyurl.com/59jtfd