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Pixel Aspect Ratio
A pixel aspect ratio (PAR) is a mathematical ratio that describes how the width of a pixel in a digital image compares to the height of that pixel. Most digital imaging systems display an image as a grid of tiny, square pixels. However, some imaging systems, especially those that must be compatible with standard-definition television motion pictures, display an image as a grid of rectangular pixels, in which the pixel width and height are different. Pixel aspect ratio describes this difference. Use of pixel aspect ratio mostly involves pictures pertaining to standard-definition television and some other exceptional cases. Most other imaging systems, including those that comply with SMPTE standards and practices, use square pixels. PAR is also known as ''sample aspect ratio'' and abbreviated ''SAR'', though it can be confused with storage aspect ratio. Introduction The ratio of the width to the height of an image is known as the aspect ratio, or more precisely the di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aspect Ratio (image)
The aspect ratio of an image is the ratio of its width to its height. It is expressed as two numbers separated by a colon, in the format width:height. Common aspect ratios are 1.85:1 and 2.39:1 in cinematography, 4:3 and 16:9 in television, and 3:2 in still photography and 1:1: Used for square images, often seen on social media platforms like Instagram, 21:9: An ultrawide aspect ratio popular for gaming and desktop monitors. Some common examples The common film aspect ratios used in cinemas are 1.85:1 and 2.39:1.The 2.39:1 ratio is commonly labeled 2.40:1, e.g., in the American Society of Cinematographers' ''American Cinematographer Manual'' (Many widescreen films before the 1970 Society of Motion Picture and Television Engineers, SMPTE revision used 2.35:1). Two common videography, videographic aspect ratios are 4:3 (1.:1), the universal video format of the 20th century, and 16:9 (1.:1), universal for high-definition television and European digital television. Other cinematic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Raster Scan
A raster scan, or raster scanning, is the rectangular pattern of image capture and reconstruction in television. By analogy, the term is used for raster graphics, the pattern of image storage and transmission used in most computer bitmap image systems. The word ''wiktionary:raster, raster'' comes from the Latin word ''wiktionary:rastrum, rastrum'' (a rake), which is derived from ''wiktionary:radere, radere'' (to scrape); see also rastrum, an instrument for drawing musical staff lines. The pattern left by the lines of a rake, when drawn straight, resembles the parallel lines of a raster: this line-by-line scanning is what creates a raster. It is a systematic process of covering the area progressively, one line at a time. Although often a great deal faster, it is similar in the most general sense to how one's gaze travels when one reads lines of text. In most modern graphics cards the data to be drawn is stored internally in an area of semiconductor memory called the framebuffer. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital-to-analog Converter
In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. DACs are commonly used in music players to convert digital data streams into analog audio signals. They are also used in televisions and mobile phones to convert digital video data into analog video signals. These two applications use DACs at opposite ends of the frequency/resolution trade-off. The audio DAC is a low-frequency, high-resolution type while the video DAC is a high-frequency low- to medium-resolution type. There are several DAC architectures; the suitability of a DAC for a particular application is determined by figures of merit including: resolution, maximum sampling frequency and others. Digital-to-analog conversion can degrade a signal, so a DAC should be specified that has insignificant errors in terms of the application. Due to the complexity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Editing
Video editing is the post-production and arrangement of video shots. To showcase excellent video editing to the public, video editors must be reasonable and ensure they have a thorough understanding of film, television, and other sorts of videography. Video editing structures and presents all video information, including films and television shows, video advertisements and video essays. Video editing has been dramatically democratized in recent years by editing software available for personal computers. Editing video can be difficult and tedious, so several technologies have been produced to aid people in this task. Overall, video editing has a wide variety of styles and applications. Types of editing Though once the province of expensive machines called video editors, video editing software is now available for personal computers and workstations. Video editing includes cutting segments (trimming), re-sequencing clips, and adding transitions and other special effects. * Linear ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field (video)
In video, a field is one of the many still images displayed sequentially to create the impression of motion on the screen. Normally, two fields comprise one video frame in what is known as 2:1 interlacing. 3:1, 4:1 and 5:1 interlacing also exist. When the fields are displayed on a video monitor, they are "interlaced" so the content of one field will be used on all of the odd-numbered lines on the screen, and the other field will be displayed on the even lines. Converting fields to a still frame image requires a process called deinterlacing, in which the missing lines are duplicated or interpolated to recreate the information that would have been contained in the discarded field. Since each field contains only half of the information of a full frame, however, deinterlaced images do not have the resolution of a full frame. Sometimes in interlaced video, a field is called a frame, which can lead to confusion. To increase the resolution of video images, new schemes have been creat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
576i
576i is a standard-definition television, standard-definition digital video mode, originally used for Digitization, digitizing 625 lines, 625 line Analog television, analogue television in most countries of the world where the utility frequency for electric power distribution is 50 Hz. Because of its close association with the legacy colour encoding systems, it is often referred to as PAL#PAL region, PAL, PAL/SECAM or SECAM when compared to its 60 Hz (typically, see PAL-M) NTSC-colour-encoded counterpart, 480i. The ''576'' identifies a vertical resolution of 576 lines, and the ''i'' identifies it as an Interlaced video, interlaced resolution. The Refresh rate, field rate, which is 50 Hertz, Hz, is sometimes included when identifying the video mode, i.e. 576i50; another notation, endorsed by both the International Telecommunication Union in Rec. 601, BT.601 and SMPTE in SMPTE 259M, includes the frame rate, as in 576i/25. Operation In analogue television, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
480i
480i is the video mode used for standard-definition digital video in the Caribbean, Japan, South Korea, Taiwan, Philippines, Myanmar, Western Sahara, and most of the Americas (with the exception of Argentina, Paraguay, and Uruguay). The other common standard definition digital standard, used in the rest of the world, is 576i. It originated from the need for a standard to digitize analog 525 line TV (defined in BT.601) and is now used for digital TV broadcasts and home appliances such as game consoles and DVD disc players. The ''480'' identifies a vertical resolution of 480 lines, and the ''i'' identifies it as an interlaced resolution. The field rate, which is 60 Hz (or 59.94 Hz when used with NTSC color), is sometimes included when identifying the video mode, i.e. 480i60; another notation, endorsed by both the International Telecommunication Union in BT.601 and SMPTE in SMPTE 259M, includes the frame rate, as in 480i/30. Although related, it should n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
NTSC
NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170. In 1953, a second NTSC standard was adopted, which allowed for color television broadcast compatible with the existing stock of black-and-white receivers. It is one of three major color formats for analog television, the others being PAL and SECAM. ''NTSC color'' is usually associated with the System M; this combination is sometimes called NTSC II. The only other broadcast television system to use NTSC color was the System J. Brazil used System M with PAL color. Vietnam, Cambodia and Laos used System M with SECAM color – Vietnam later started using PAL in the early 1990s. The NTSC/System M standard was used in most of the Americas (except Argentina, Brazil, Paraguay, and Uruguay), Myanmar, South Korea, Taiwan, Philippines, Japan, and some Pacific Isl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Line (video)
A scan line (also scanline) is one line, or row, in a raster scanning pattern, such as a line of video on a cathode-ray tube (CRT) display of a television set or computer monitor. On CRT screens the horizontal scan lines are visually discernible, even when viewed from a distance, as alternating colored lines and black lines, especially when a progressive scan signal with below maximum vertical resolution is displayed. This is sometimes used today as a visual effect in computer graphics. The term is used, by analogy, for a single row of pixels in a raster graphics image. Scan lines are important in representations of image data, because many image file formats have special rules for data at the end of a scan line. For example, there may be a rule that each scan line starts on a particular boundary (such as a byte or word; see for example BMP file format). This means that even otherwise compatible raster data may need to be analyzed at the level of scan lines in order to convert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard-definition Television
Standard-definition television (SDTV; also standard definition or SD) is a television system that uses a resolution that is not considered to be either high or enhanced definition. ''Standard'' refers to offering a similar resolution to the analog broadcast systems used when it was introduced. History and characteristics SDTV originated from the need for a standard to digitize analog TV (defined in BT.601) and is now used for digital TV broadcasts and home appliances such as game consoles and DVD disc players. Digital SDTV broadcast eliminates the ghosting and noisy images associated with analog systems. However, if the reception has interference or is poor, where the error correction cannot compensate one will encounter various other artifacts such as image freezing, stuttering, or dropouts from missing intra-frames or blockiness from missing macroblocks. The audio encoding is the last to suffer a loss due to the lower bandwidth requirements. Standards that suppor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video Compression
In information theory, data compression, source coding, or bit-rate reduction is the process of encoding information using fewer bits than the original representation. Any particular compression is either lossy or lossless. Lossless compression reduces bits by identifying and eliminating Redundancy (information theory), statistical redundancy. No information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information. Typically, a device that performs data compression is referred to as an encoder, and one that performs the reversal of the process (decompression) as a decoder. The process of reducing the size of a data file is often referred to as data compression. In the context of data transmission, it is called source coding: encoding is done at the source of the data before it is stored or transmitted. Source coding should not be confused with channel coding, for error detection and correction or line coding, the means ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Video
Video is an Electronics, electronic medium for the recording, copying, playback, broadcasting, and display of moving picture, moving image, visual Media (communication), media. Video was first developed for mechanical television systems, which were quickly replaced by cathode-ray tube (CRT) systems, which, in turn, were replaced by flat-panel displays of several types. Video systems vary in display resolution, Display aspect ratio, aspect ratio, refresh rate, color capabilities, and other qualities. Analog and digital variants exist and can be carried on a variety of media, including radio broadcasts, magnetic tape, optical discs, Video file format, computer files, and Streaming media, network streaming. Etymology The word ''video'' comes from the Latin verb ''video,'' meaning to see or ''videre''. And as a noun, "that which is displayed on a (television) screen," History Analog video Video developed from facsimile systems developed in the mid-19th century. Early mecha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
