The acronym HD has different uses, generally derived from the English language . One of the most common refers to high definition : that is, high definition .
An HD device or system, therefore, has an image or sound resolution that is higher than standard definition. In this way, HD equals higher quality .
HD made it possible to increase the number of lines and the frame rate and improve the aspect ratio. Thanks to digital technology , the necessary compression was achieved to reduce the bandwidth needed to transmit content with these characteristics.
An HD television , in short, can display more pixels and colors than a conventional one. Anyway, HD technology was perfected with Full HD and Ultra HD . It is important to keep in mind that, for the viewer to be able to enjoy it in HD, the material must have been recorded, edited, transmitted and reproduced under these quality standards .
High definition began as a great revolution for graphic content in the late 90s, first in cinema and, later, in the field of video games. Although in theory it is merely an increase in the number of pixels per static image, in the background there was a multimillion-dollar investment in various fields of research and development to increase the complexity of all the objects on the screen.
It is very important to understand the differences between drawings made by pixels and three-dimensional models; While the former are recorded in a file that does not differ much from a list in which the color of each pixel is specified, and then displayed on the screen with almost no intermediate processes, three-dimensional models contain much more information, such as the location and rotation of each vertex, the lighting sources and the properties of the surfaces on which it impacts. All of this must be calculated on each frame to convert the scene into an image that can be displayed on the screen, and the processing power required for this is much greater.
For this reason, to ensure the success of HD televisions and monitors, an evolution in graphics cards, processors and computer memory was necessary, so that they could process three-dimensional graphics and convert them into very detailed high-definition images. As mentioned above, color is another aspect that improved with the arrival of HD and, later, Full HD and Ultra HD. However, resolution and color do not go hand in hand.
Engineers decided to improve the screen 's capabilities to display more colors simultaneously, simply to accentuate the increase in resolution, but they could have easily skipped this step. What prompted you to take both revolutions hand in hand? The fact that most consumers cannot tell the difference between standard and high definition, but have less difficulty noticing the increase in color depth.
An HD or HDD, on the other hand, is a hard disk : a hard disk or rigid drive . It is a data storage unit that allows you to save digital files.
HD uses magnetic recording , using discs or platters that rotate in a sealed box. On the faces of these disks there are read/write heads that are responsible for recording and reproducing the information .
The first HD was created in the mid- 1950s by IBM . Since then, its storage capacity has multiplied several times. Today HDs constitute the main resource for storing data on a computer .