Video Terminology Basics 101, Part 2 - Resolution
Size matters in video. But it is a confusing topic because it could mean one of two different (but related) things: file size orimage size. File size is governed by a concept called compression, which I'll cover in more detail in the next article. Image size is a different topic having to do with resolution. Resolution is the primary video term that most folks already have a decent understanding of, but there can still be some confusion.
Most husbands these days have already convinced their wives of the necessity of a high definition television, so most wives wake up daily to a giant rectangular monstrosity mounted on their living room wall. People already get that 1080P and 720P are designations for types of HD video displays. Most people also recognize that the number has something to do with the image crispness—the higher the number, the better the image. This is mostly correct and a great starting point.
1080P, 720P and 480P are all common ways to describe resolution. The "P" stands for "progressive" which just means full frame and isn't relevant enough to the layperson to get into in much detail here. I will say this though, progressive refers to a sequence of fully formed still images, one after another, much like frames of traditional film. P is a good thing.
The number stands for the vertical number of dots (called pixels) that make up the image. 1080P means 1,920 dots long by 1,080 dots high for a total of over 2 million dots. Those two million plus dots make up the image. The more dots, the clearer and crisper the image and the less jagged the edges of objects will appear. Old standard definition video (the video from the 90s) was only 720 dots long by 480 dots high, making for only about 300,000 dots total. It's easy to see why a far crisper and larger image can be made out of 2 million dots than from 300,000 dots. Easy enough.
But here's the key concept that a lot of folks fail to understand. Resolution refers to two separate things: display technology and native video resolution. It is important to make a distinction between these two things. In most cases, video professionals are talking about the resolution of the video footage itself, not the display it will eventually be played back on. Video pros are referring to the image size of video files that the camera shot or that were created in the computer as an animation. This is usually the resolution of the final edited video created from the footage and what ends up getting broadcast or streamed online.
If a 480P video is played back on a 1080P HD television display, it will not make it look like high definition video. The nature of resolution is first defined by the video file itself. Then that video footage, in order to be seen in all it's glory, will need to be played back on a display that supports that resolution.
There's another format coming along in the near future called 4K, that is essentially ultra high definition. 4K footage is made up of around 9.5 million dots per image, 4-5 times as much image information as 1080P HD.
Here's an overview of the key points:
- Video size refers to two separate topics: file size (this deals with compression) and image size (resolution).
- Video resolution is defined by the total number of dots called pixels that make up the image. The more dots, the larger and crisper the image.
- Video resolution refers to two separate things: display technology (your TV or computer monitor) and the resolution of the video file itself. The latter is usually what most video professionals are referring to.
In the next article, I'll cover the other side of video size, file size which deals with a topic called compression.
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