What is High Definition?
• A. High Definition (HD) is a high-resolution video format that offers 3x the detail (resolution) available in Standard Definition (SD) for stunning clarity and an immensely sharper image. That’s 3x the resolution detail than your television! HD allows you to see the fine details from eyelashes on a newborn to the foamy mist from crashing waves at sunset. A visual comparison between 480p SD (TV Quality), 720p HD (Better), and 1080p HD (Best) is below that shows just how small and lacking in detail SD TV quality is compared to HD.
HDTV (High Definition Television) is an emerging high resolution standard for television and DVD formats. There are 2 resolutions which can be defined as high definition, 1280*720 and 1920*1080, both in 16:9 widescreen aspect ratio. In order to be defined as high definition ready, a display device (projector, plasma, lcd etc.) must meet the following criteria: i. The device must physically have a minimum of 720 lines in wide aspect ratio. ii. The device must be able to accept 1280 x 720p and 1920 x 1080i at 50 and 60Hz iii. The DVI or HDMI input must support content protection (HDCP) It is on point ii. that many devices fail. Although many devices support a native resolution of 1280*720 or more, some cannot accept a 720p or 1080i signal at 50Hz and require that the frequency be increased to 60Hz, which usually involves using a scaler. You should bear this in mind before you purchase. The other point to keep in mind when purchasing your display is the native resolution. For example, alt
HDTV is high-resolution digital television (DTV) combined with Dolby Digital surround sound (AC-3). HDTV is the highest DTV resolution in the new set of standards. This combination creates a stunning image with stunning sound. HDTV requires new production and transmission equipment at the HDTV stations, as well as new equipment for reception by the consumer. The higher resolution picture is the main selling point for HDTV. Imagine 720 or 1080 lines of resolution compared to the 525 lines people are used to in the United States (or the 625 lines in Europe) — it’s a huge difference! Stations are free to choose which formats to broadcast. The formats used in HDTV are: 720p – 1280×720 pixels progressive 1080i – 1920×1080 pixels interlaced 1080p – 1920×1080 pixels progressive “Interlaced” or “progressive” refers to the scanning system. In an interlaced format, the screen shows every odd line at one scan of the screen, and then follows that up with the even lines in a second scan. Since the
If you have read How Television Works, then you know all about what is now called analog TV. In analog TV, a 6 MHz analog signal carries intensity and color information for each scan line of the picture. An analog TV signal in the U.S. has 525 scan lines for the image, and each image is refreshed every 30th of a second (half of the scan lines are painted every sixtieth of a second in what is called an interlaced display). The horizontal resolution is something like 500 dots for a color set. This level of resolution was amazing 50 years ago, but today it is rather passé. The lowest resolution computer monitor that anyone uses today has 640×480 pixels, and most people use a resolution like 800×600 or 1024×768. We have grown comfortable with the great clarity and solidity of a computer display, and analog TV technology pales by comparison. Many of the new satellite systems, as well as DVDs, use a digital encoding scheme that provides a much clearer picture. In these systems, the digital i
