HD video is a high definition recording with a higher resolution than standard. However, there is no unambiguous definition regarding HD. What permission corresponds to it depends on the specific region. So, in the countries of North America, traditionally any video containing more than 480 horizontal lines was considered a high-definition recording. In the countries of Europe it should have totaled 570 such units. However, today these figures are much higher.
Recordings with HD-resolution can have various sources: terrestrial or direct satellite broadcasting, digital cable television, disks (CDs), digital cameras, Internet content and the latest generation of game consoles. Most computers can play this kind of video thanks to VGA, DVI and / or HDMI.
A standard optical Blu-ray disc can provide ample storage space for several hours of high-definition recording. Digital Versatile or DVDs (having 4.7 GB of space or 8.5 GB of double-sided recording) play better on screens that are smaller than 36 inches (91 cm) because they often cannot support high resolution HD (by modern standards) .
Depending on the available bandwidth and the number of parts, the optimal format for video transmission is either 720p / 24 frames per second or 1080 p / 24. In some countries, other standards apply - a speed of 25 or even 30 frames per second is used. Previously, when using video tapes, a resolution of 480 or 576 pixels was used. Such recordings can be converted to 720p format, but such formatting may distort the picture or require filtering, which actually reduces the quality of the output signal. HDTV format video already has an HD resolution of 720 or 1080 p.
In general terms, the 720 format is more accurate and faster, since frames are downloaded gradually during its playback. The 1080 standard, in contrast, uses interlaced scanning, and thus can reduce the speed of video downloads. For this reason, the resolution of 720 p, as a rule, is used to download video from the Internet or to view on the network, 1080 p - to record discs using Blu-ray technology.
The number of streaming videos offered for viewing online or downloading on the Internet is growing daily. Despite the fact that such files are recommended as high-definition recordings, it cannot be argued that they have HD resolution. Due to the strong compression and detail of images created by these formats, their quality is much lower and often even inferior to DVD-Video.
In addition, an increasing number of manufacturers of surveillance cameras offer products with high-definition video recording. In this case, HD-resolution is necessary, since the events recorded by the camcorder in some cases can play a significant role. This technology ensures proper color reproduction and frame rate. However, it must be remembered that such videos require an appropriate amount of storage space.
Today, some game consoles support games that have a 1080p image. This opportunity was immediately appreciated positively. In addition to enhancing the visual quality of the game, users were also able to download or transfer HD movies and video clips using the PlayStation Network. PlayStation 3 can also play Blu-ray, which contains HD data.