Webcams fall into an ill-defined area between digital cameras and video camcorders. Today, webcams have the ability to take both great quality pictures and to capture high-definition video. Due to webcams falling in this grey area, there is no set standard for how to describe each webcam's capabilities. One webcam may be listed as 2.0 megapixels and another as 1080p. This webcam has a normal aspect ratio, but this one has a 16:9 aspect ratio. At this point, you may be wondering, like the Double Rainbow Guy What does all this mean? Below, we cut through confusing tech jargon so you'll know exactly what each camera can do.
HD or High Definition
720p and 1080p are high-definition resolutions, with 1080p being the best available. What does the "p" mean, you might be asking yourself. It's short for "progressive scanning." For example, 720p really means 1280x720 pixels, where 1280 represents the number of horizontal pixels and 720 represents the number of vertical pixels. A 720p television will progressively scan 921,600 pixels (1280x720) on the screen every 1/60 of a second. The more pixels that can be progressively scanned onscreen, the better the video quality.
Megapixels are an image quality descriptions usually associated with digital cameras. Taking our last example of 1280x720, or 921,600 pixels, this would come to .9 megapixels (MP), or one megapixel if you round up (mega means one million). As you can see, the formula to arrive at both descriptions of resolution are exactly the same, just described differently.
There are two main reasons why webcams are either described in megapixels or in HD resolution. The first reason is that some consumers can easily identify with a product that has its resolution described in megapixels as opposed to HD resolution and vise versa. The other reason for the two different descriptions for video resolution is a separate measurement: the aspect ratio.
The aspect ratio is a common reason why a webcam is either described as HD or in terms of the number of megapixels. HD webcams, or webcams that are described in terms of 720p or 1080p resolution, have an aspect ratio of 16:9, which is a widescreen view.
When it comes to a webcam that has a normal aspect ratio, you are more likely to see the resolution listed in terms of megapixels. When you see a webcam for which the video resolution is listed in megapixels, expect the picture to be as tall as it is wide.
VGA is a sensor type that usually refers to 640x480 resolution, which is the same resolution of a standard definition television. Webcams that are VGA are not considered high-definition webcams. These are entry-level webcams that shoot video at a resolution of 640x480 pixels, or .3 megapixels or below. This type of webcam comes from an early technology, whereas most high-definition webcams now have CMOS sensors.
You may notice that a webcam may not have great video quality but is still able to take high quality photos. This doesn't necessarily have anything to do with the webcam itself. The software that comes with the webcam is what digitally enhances the quality of the pictures. When you see that a webcam can take up to 20MP interpolated photos, it actually means that the webcam itself doesn't have that capability, but the software can upgrade the quality of the photos to 20MP.
Frame rate is an extremely important specification to recognize. Frame rate is usually described in terms of frames per second (FPS). The higher the frame rate, the more fluid the streaming video will be. You will find webcams that have HD-quality video 1080p resolution but have better quality video with less skipping or choppiness at 720p at 30FPS. This is because at 1080p, the webcam and CPU have to process much more information than at 720p, thus slowing the frame rate down to 10FPS or lower, which in turn creates less fluid video.
Most webcams with a built-in H.264 video encoder have the ability to process video at a much faster rate, causing less strain on the CPU and webcam, thus keeping the fluidity of the video and maintaining the image quality. If you can find a webcam with a H.264 video encoder inside it, you will more than likely have the ability to shoot true high-definition video.