High-definition television (HDTV)
High-definition television (HDTV) represents a significant advancement in television technology, offering much higher image resolution than standard-definition television (SDTV). The clarity of HDTV images is achieved through various formats, notably 1080p, 1080i, and 720p, where "p" stands for progressive scan, displaying all lines of an image simultaneously, and "i" represents interlaced scanning, which alternates lines. A key feature of HDTV is its ability to provide a wider aspect ratio and a higher pixel count, enhancing the viewer's experience and making images appear more lifelike.
The development of HDTV began in Japan during the 1970s, evolving from early analog systems to digital technology in the 1990s, culminating in the first public HDTV broadcast in 1996. As of 2015, analog television transmissions were entirely phased out, solidifying digital HDTV as the standard. The introduction of HDTV has led to innovations across various media platforms, including Blu-ray players and streaming services like Netflix, which offer high-definition content. By 2012, HDTVs had become commonplace, with over 75% of U.S. households owning one, reflecting the technology's widespread acceptance and integration into modern entertainment.
High-definition television (HDTV)
High-definition television (HDTV) is a mode of television broadcast that is much higher in image resolution, or quality, than standard-definition television (SDTV). A high resolution makes a picture much clearer to viewers. HDTV can be transmitted in several formats: 1080p, 1080i, or 720p. “P” stands for progressive scan, which means the lines of resolution in each moving image are displayed together. “I” stands for interlaced, which means the lines of the transmitted images are displayed alternately, so that the signal contains two opposite video frames captured at two different times. Progressive scan offers superior image quality compared to interlaced. Each of these formats projects images with different amounts of pixels per frame. Pixels are small dots that together form a picture on a TV screen. The smaller the pixel, the clearer the image or resolution.
Modern HDTV got its start in 1970s Japan and has since spawned into a multimillion-dollar industry with endless potential for improvement. HDTV technology is commonly found in many electronic products. HDTV is installed in most modern television sets. Many cable TV providers also cater to the HDTV audience by broadcasting HD versions of their channels.
Background
Early high-definition technology initiatives attempted to produce advanced imaging through the use of analog broadcast. When researchers realized the limits presented by analog broadcasting, new methods were developed to further improve resolution. Television display formats consist of four elements: aspect ratio, raster, scanning method, and refresh rate. Aspect ratio is the ratio of the width of an image to its height. Raster refers to the way an image is constructed for broadcast by the vertical arrangement of a continuous number of horizontal lines of resolution. The scanning method is the way lines are drawn across the screen. Lastly, the refresh rate describes the number of times per second a new image is shown. The way in which each of these attributes is defined affects the quality of the projected image. Early televisions were incapable of advanced image definition. Traditional analog aspect ratios were a standard 4:3 display with a 2:1 interlaced scanning method, which meant that all odd lines were presented in one field, and all even lines were presented in a different field. These lines were then interlaced to produce the image in the frame. This method often produced blurred images. Early broadcasting systems usually ranged between 400 and 600 lines per frame. When digital technology began dominating the market, television systems saw an expansion in display possibilities.
Early Digital HDTV History and Development
The first digital high-definition technology developed from studies conducted by Japan’s NHK (Japan Broadcasting Corporation) in the 1970s. In 1977, Japan’s Society of Motion Picture and Television Engineers began researching high-definition television more extensively and by the 1980s had published recommendations for the definition of wide-screen format and 1100-line scanning structure. They demonstrated their findings in 1981 and quickly drew a great deal of interest. By the end of the 1980s, the interest in advanced television technology (ATV) had extended to the United States. The Federal Communications Commission (FCC) formed the Advisory Committee on Advanced Television Service in 1987, and by the early 1990s, the committee was considering a proposal that outlined an all-digital approach to advanced television system design.
The U.S. Congress and the FCC fielded several other advanced TV proposals throughout the early 1990s but deemed digital HDTV as the most valuable technology, mandating an all-digital ATV standard for HDTV broadcasting in 1996. The first HDTV broadcast occurred shortly after this mandate on July 23, 1996, by WRAL-TV, making the station the first to demonstrate HDTV to the public. Over the next decade, the FCC began the gradual phasing out of analog television altogether. Designating September 1, 2015, as the official conversion date, transmission of analog television would cease completely, and all broadcasts would be switched to a digital format. Consumers still in possession of an analog television at this time were obligated to purchase affordable converter boxes so their televisions could transmit the digital signal.
The Rise of HDTV
HDTV technology was developed to improve viewer experience. The goal was to create image technology that would make people believe they were seeing the real thing. Modern HDTV offers a much greater resolution than its predecessor, the standard definition television (SDTV). For example, a 1080i HDTV signal has a resolution six times greater than a 480i SDTV signal. HDTV also allows for a wider aspect ratio that more closely resembles a person’s visual perception of a scene. HDTV has three standard image resolutions. A 720p display normally has a resolution 720 pixels high and 1280 pixels wide and is transmitted through a progressive scan signal, which provides the highest quality of images. The aspect ratio of a 720p display is usually 16:9, which is considered a wide-screen format. HDTV sets also offer 1080p/i displays. Though these displays have a similar aspect ratio, they are higher in resolution and are often called Full HD displays. Some televisions are now capable of providing pictures in 4k, 8k, OLED, or QLED. Each offers a unique, high-quality viewing experience.
HDTV technology has led to a number of innovations in various entertainment markets. Blu-ray video disc players were developed to offer consumers the greatest HD video resolution when viewing films or playing video games at home. Game consoles such as Sony’s PlayStation 3 and Microsoft’s Xbox 360 came equipped with HD compatibility. Video streaming websites such as Netflix and Hulu also utilize HD technology to display movies and TV shows. Most cable companies now offer network television in HD format as well.
Bibliography
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