High-definition video (HD video) is video of higher resolution and quality than standard-definition. While there is no standardized meaning for high-definition, generally any video image with considerably more than 480 vertical scan lines (North America) or 576 vertical lines (Europe) is considered high-definition.[ citation needed ] 480 scan lines is generally the minimum even though the majority of systems greatly exceed that. Images of standard resolution captured at rates faster than normal (60 frames/second North America, 50 fps Europe), by a high-speed camera may be considered high-definition in some contexts. Some television series shot on high-definition video are made to look as if they have been shot on film, a technique which is often known as filmizing.
The first electronic scanning format, 405 lines, was the first high definition television system, since the mechanical systems it replaced had far fewer. From 1939, Europe and the US tried 605 and 441 lines until, in 1941, the FCC mandated 525 for the US. In wartime France, René Barthélemy tested higher resolutions, up to 1,042. In late 1949, official French transmissions finally began with 819. In 1984, however, this standard was abandoned for 625-line color on the TF1 network.
Modern HD specifications date to the early 1980s, when Japanese engineers developed the HighVision 1,125-line interlaced TV standard (also called MUSE) that ran at 60 frames per second. The Sony HDVS system was presented at an international meeting of television engineers in Algiers, April 1981 and Japan's NHK presented its analog high-definition television (HDTV) system at a Swiss conference in 1983.
The NHK system was standardized in the United States as Society of Motion Picture and Television Engineers (SMPTE) standard #240M in the early 1990s, but abandoned later on when it was replaced by a DVB analog standard. HighVision video is still usable for HDTV video interchange, but there is almost no modern equipment available to perform this function. Attempts at implementing HighVision as a 6 MHz broadcast channel were mostly unsuccessful. All attempts at using this format for terrestrial TV transmission were abandoned by the mid-1990s.[ citation needed ]
Europe developed HD-MAC (1,250 lines, 50 Hz), a member of the MAC family of hybrid analogue/digital video standards; however, it never took off as a terrestrial video transmission format. HD-MAC was never designated for video interchange except by the European Broadcasting Union.
High-definition digital video was not possible with uncompressed video due to impractically high memory and bandwidth requirements, with a bit rate exceeding 1 Gbit/s for 1080p video. [1] Digital HDTV was enabled by the development of discrete cosine transform (DCT) video compression. [2] The DCT is a lossy compression technique that was first proposed by Nasir Ahmed in 1972, [3] and was later adapted into a motion-compensated DCT algorithm for video coding formats such as the H.26x formats from the Video Coding Experts Group from 1988 onwards and the MPEG formats from 1993 onwards. [4] [5] Motion-compensated DCT compression significantly reduced the amount of memory and bandwidth required for digital video, capable of achieving a data compression ratio of around 100:1 compared to uncompressed video. [6] By the early 1990s, DCT video compression had been widely adopted as the video coding standard for HDTV. [2]
The current high-definition video standards in North America were developed during the course of the advanced television process initiated by the Federal Communications Commission in 1987 at the request of American broadcasters. In essence, the end of the 1980s was a death knell for most analog high definition technologies that had developed up to that time.
The FCC process, led by the Advanced Television Systems Committee (ATSC) adopted a range of standards from interlaced 1,080-line video (a technical descendant of the original analog NHK 1125/30 Hz system) with a maximum frame rate of 30 Hz, (60 fields per second) and 720-line video, progressively scanned, with a maximum frame rate of 60 Hz.
In the end, however, the DVB standard of resolutions (1080, 720, 480) and respective frame rates (24, 25, 30) were adopted in conjunction with the Europeans that were also involved in the same standardization process. The FCC officially adopted the ATSC transmission standard in 1996 (which included both HD and SD video standards).
In the early 2000s, it looked as if DVB would be the video standard far into the future. However, both Brazil and China have adopted alternative standards for high-definition video[ citation needed ] that preclude the interoperability that was hoped for after decades of largely non-interoperable analog TV broadcasting.
High definition video (prerecorded and broadcast) is defined threefold, by:
Often, the rate is inferred from the context, usually assumed to be either 50 Hz (Europe) or 60 Hz (USA), except for 1080p, which denotes 1080p24, 1080p25, and 1080p30, but also 1080p50 and 1080p60.
A frame or field rate can also be specified without a resolution. For example, 24p means 24 progressive scan frames per second and 50i means 25 progressive frames per second, consisting of 50 interlaced fields per second. Most HDTV systems support some standard resolutions and frame or field rates. The most common are noted below. High-definition signals require a high-definition television or computer monitor in order to be viewed. High-definition video has an aspect ratio of 16:9 (1.78:1). The aspect ratio of regular widescreen film shot today is typically 1.85:1 or 2.39:1 (sometimes traditionally quoted at 2.35:1). Standard-definition television (SDTV) has a 4:3 (1.33:1) aspect ratio, although in recent years many broadcasters have transmitted programs squeezed horizontally in 16:9 anamorphic format, in hopes that the viewer has a 16:9 set which stretches the image out to normal-looking proportions, or a set which squishes the image vertically to present a letterbox view of the image, again with correct proportions.
The EU defines HD resolution as 1920 x 1080 pixels or 2 073 600 pixels and UHD resolution as 3840 x 2160 pixels or 8 294 400 pixels. [7]
Video mode | Frame size in pixels (W×H) | Pixels per image1 | Scanning type | Frame rate (Hz) |
---|---|---|---|---|
720p (also known as HD Ready) | 1,280×720 | 921,600 | Progressive | 23.976, 24, 25, 29.97, 30, 50, 59.94, 60, 72 |
1080i (also known as Full HD) | 1,920×1,080 | 2,073,600 | Interlaced | 25 (50 fields/s), 29.97 (59.94 fields/s), 30 (60 fields/s) |
1080p (also known as Full HD) | 1,920×1,080 | 2,073,600 | Progressive | 24 (23.976), 25, 30 (29.97), 50, 60 (59.94) |
1440p (also known as Quad HD) | 2,560×1,440 | 3,686,400 | Progressive | 24 (23.976), 25, 30 (29.97), 50, 60 (59.94) |
Video mode | Frame size in pixels (W×H) | Pixels per image1 | Scanning type | Frame rate (Hz) |
---|---|---|---|---|
2000 | 2,048×1,536 | 3,145,728 | Progressive | 24, 30, 60 |
2160p (also known as 4K UHD) | 3,840×2,160 | 8,294,400 | Progressive | 60, 120 |
2540p | 4,520×2,540 | 11,480,800 | Progressive | 24, 30, 60 |
4000p | 4,096×3,072 | 12,582,912 | Progressive | 24, 30, 60 |
4320p (also known as 8K UHD) | 7,680×4,320 | 33,177,600 | Progressive | 60, 120 |
Note: 1 Image is either a frame or, in case of interlaced scanning, two fields (EVEN and ODD).
Also, there are less common but still popular UltraWide resolutions, such as 2560×1080p (1080p UltraWide).
There is also a WQHD+ option for some of these.
This section needs to be updated.(March 2024) |
High-definition image sources include terrestrial broadcast, direct broadcast satellite, digital cable, high definition disc (BD), digital cameras, Internet downloads, and video game consoles.
Blu-ray Discs were jointly developed by 9 initial partners including Sony and Phillips (which jointly developed CDs for audio), and Pioneer (which developed its own Laser-disc previously with some success) among others. HD DVD discs were primarily developed by Toshiba and NEC with some backing from Microsoft, Warner Bros., Hewlett Packard, and others. On February 19, 2008, Toshiba announced it was abandoning the format and would discontinue development, marketing and manufacturing of HD DVD players and drives.
The high resolution photographic film used for cinema projection is exposed at the rate of 24 frames per second but usually projected at 48, each frame getting projected twice helping to minimise flicker. One exception to this was the 1986 National Film Board of Canada short film Momentum , which briefly experimented with both filming and projecting at 48 frame/s, in a process known as IMAX HD.
Depending upon available bandwidth and the amount of detail and movement in the image, the optimum format for video transfer is either 720p24 or 1080p24. When shown on television in PAL system countries, film must be projected at the rate of 25 frames per second by accelerating it by 4.1 percent. In NTSC standard countries, the projection rate is 30 frames per second, using a technique called 3:2 pull-down. One film frame is held for three video fields (1/20 of a second), and the next is held for two video fields (1/30 of a second) and then the process is repeated, thus achieving the correct film projection rate with two film frames shown in one twelfth of a second.
Older (pre-HDTV) recordings on video tape such as Betacam SP are often either in the form 480i60 or 576i50. These may be upconverted to a higher resolution format, but removing the interlace to match the common 720p format may distort the picture or require filtering which actually reduces the resolution of the final output.
Non-cinematic HDTV video recordings are recorded in either the 720p or the 1080i format. The format used is set by the broadcaster (if for television broadcast). In general, 720p is more accurate with fast action, because it progressively scans frames, instead of the 1080i, which uses interlaced fields and thus might degrade the resolution of fast images.
720p is used more for Internet distribution of high-definition video, because computer monitors progressively scan; 720p video has lower storage-decoding requirements than either the 1080i or the 1080p. This is also the medium for high-definition broadcasts around the world and 1080p is used for Blu-ray movies.
Film as a medium has inherent limitations, such as difficulty of viewing footage while recording, and suffers other problems, caused by poor film development/processing, or poor monitoring systems. Given that there is increasing use of computer-generated or computer-altered imagery in movies, and that editing picture sequences is often done digitally, some directors have shot their movies using the HD format via high-end digital video cameras. While the quality of HD video is very high compared to SD video, and offers improved signal/noise ratios against comparable sensitivity film, film remains able to resolve more image detail than current HD video formats. In addition some films have a wider dynamic range (ability to resolve extremes of dark and light areas in a scene) than even the best HD cameras. Thus the most persuasive arguments for the use of HD are currently cost savings on film stock and the ease of transfer to editing systems for special effects.
Depending on the year and format in which a movie was filmed, the exposed image can vary greatly in size. Sizes range from as big as 24 mm × 36 mm for VistaVision/Technirama 8 perforation cameras (same as 35 mm still photo film) going down through 18 mm × 24 mm for Silent Films or Full Frame 4 perforations cameras to as small as 9 mm × 21 mm in Academy Sound Aperture cameras modified for the Techniscope 2 perforation format. Movies are also produced using other film gauges, including 70 mm films (22 mm × 48 mm) or the rarely used 55 mm and CINERAMA.
The four major film formats provide pixel resolutions (calculated from pixels per millimeter) roughly as follows:
In the process of making prints for exhibition, this negative is copied onto other film (negative → interpositive → internegative → print) causing the resolution to be reduced with each emulsion copying step and when the image passes through a lens (for example, on a projector). In many cases, the resolution can be reduced down to 1/6 of the original negative's resolution (or worse).[ citation needed ] Note that resolution values for 70 mm film are higher than those listed above.
Many online video streaming, on-demand and digital download services offer HD video. Due to heavy compression, the image detail produced by these formats can be far below that of broadcast HD, and often even inferior to DVD-Video (3-9 Mbit/s MP2) upscaled to the same image size. [8] The following is a chart of numerous online services and their HD offering:
Source | Codec | Highest resolution (W×H) | Total bit rate/bandwidth | Video bit rate | Audio bit rate |
---|---|---|---|---|---|
Amazon Video [note 1] | VC-1 [9] | 1280×720 [10] | 2.5-6 Mbit/s | ||
BBC iPlayer | H.264 [11] | 1280×720 [12] [note 2] | 3.2 Mbit/s [11] | 3 Mbit/s [11] | 192 kbit/s [11] |
blinkbox | 1280×720 | 2.25 Mbit/s (SD) and 4.5 Mbit/s (HD) | 2.25 - 4.5 Mbit/s | 192 kbit/s | |
Blockbuster Online | 1280×720 | ||||
CBS.com/TV.com | 1920×1080 [13] | 3.5 Mbit/s and 2.5 Mbits (720p) [13] | |||
Dacast | VP6, H.264 [14] | Unknown | 5 Mbit/s [15] | ||
Hulu | On2 Flash VP6 [16] | 1280×720 [17] | 2.5 Mbit/s [18] | ||
iTunes/Apple TV | QuickTime H.264 [19] | 1920×1080 [19] | |||
MetaCDN | MPEG-4, FLV, OGG, WebM, 3GP [20] | No Limit [21] | |||
Netflix | VC-1 [22] | 3840×2160 [23] | 25 Mbit/s [24] | 2.6 Mbit/s and 3.8 Mbit/s (1080p) [25] | |
PlayStation Video | H.264/MPEG-4 AVC [26] | 1920×1080 [26] | 8 Mbit/s [26] | 256 kbit/s [26] | |
Vimeo | H.264 [27] | 1920×1080 [28] | 4 Mbit/s [29] | 320 kbit/s [30] | |
Vudu | H.264 [31] | 1920×1080 [32] | 4.5 Mbit/s [33] | ||
Xbox Video [note 3] | 1920×1080 [34] | ||||
YouTube | H.264/MPEG-4 AVC, VP9, AV1 | 7680×4320 |
Since the late 2000s a considerably large number of security camera manufacturers have started to produce HD cameras. The need for high resolution, color fidelity, and frame rate is acute for surveillance purposes to ensure that the quality of the video output is of an acceptable standard that can be used both for preventative surveillance as well as for evidence purposes. [35]
Although, HD cameras can be highly effective indoor, special industries with outdoor environments called for a need to produce much higher resolutions for effective coverage. The ever-evolving image sensor technologies allowed manufacturers to develop cameras with 10-20 MP resolutions, which therefore have become efficient instruments to monitor larger areas.
In order to further increase the resolution of security cameras, some manufacturers developed multi-sensor cameras. Within these devices several sensor-lens combinations produce the images, which are later merged during image processing. [36] These security cameras are able to deliver even hundreds of megapixels with motion picture frame rate.
Such high resolutions, however, requires special recording, storage and also video stream display technologies.
Both the PlayStation 3 [37] the Xbox 360 [38] game consoles can output native 1080p through HDMI or component cables, but the systems have few games which appear in 1080p; most games only run natively at 720p or less but can be upscaled to 1080p. Visually, native 1080p produces a sharper and clearer picture compared to upscaled 1080p.[ citation needed ] The Wii does not support HD. [39] In the 8th generation, Nintendo's Wii U [40] and Nintendo Switch, [41] Microsoft's Xbox One, and Sony's PlayStation 4 display games 1080p natively. [42] The Nintendo Switch is an unusual case, due to its hybrid nature as both a home console and a handheld: the built-in screen displays games at 720p maximum, but the console can natively display imagery at 1080p when docked. [41] The Xbox One X and PlayStation 4 Pro can display some games in 4K. [42] The PlayStation 5 and Xbox Series X can display games in 4K and 8K. [43]
Generally, PC games are only limited by the display's resolution and GPU driver support. Some PC hardware supports DisplayPort 2.1 for native 8k resolution at high refresh rates. [44] Ultrawide monitors are supported, which can display more of the game world than a traditional display with a 16:9 aspect ratio, [45] and multi-monitor setups are possible, such as having a single game span across three monitors for a more immersive experience. [46]
Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises a series of digital images displayed in rapid succession, usually at 24, 25, 30, or 60 frames per second. Digital video has many advantages such as easy copying, multicasting, sharing and storage.
Interlaced video is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured consecutively. This enhances motion perception to the viewer, and reduces flicker by taking advantage of the characteristics of the human visual system.
Progressive scanning is a format of displaying, storing, or transmitting moving images in which all the lines of each frame are drawn in sequence. This is in contrast to interlaced video used in traditional analog television systems where only the odd lines, then the even lines of each frame are drawn alternately, so that only half the number of actual image frames are used to produce video. The system was originally known as "sequential scanning" when it was used in the Baird 240 line television transmissions from Alexandra Palace, United Kingdom in 1936. It was also used in Baird's experimental transmissions using 30 lines in the 1920s. Progressive scanning became universally used in computer screens beginning in the early 21st century.
Telecine, or TK, is the process of transferring film into video and is performed in a color suite. The term is also used to refer to the equipment used in this post-production process.
Enhanced-definition television, or extended-definition television (EDTV) is a Consumer Electronics Association (CEA) marketing shorthand term for certain digital television (DTV) formats and devices. Specifically, this term defines an extension of the standard-definition television (SDTV) format that enables a clearer picture during high-motion scenes compared to previous iterations of SDTV, but not producing images as detailed as high-definition television (HDTV).
In video technology, 24p refers to a video format that operates at 24 frames per second frame rate with progressive scanning. Originally, 24p was used in the non-linear editing of film-originated material. Today, 24p formats are being increasingly used for aesthetic reasons in image acquisition, delivering film-like motion characteristics. Some vendors advertise 24p products as a cheaper alternative to film acquisition.
HD-MAC was a broadcast television standard proposed by the European Commission in 1986, as part of Eureka 95 project. It belongs to the MAC - Multiplexed Analogue Components standard family. It is an early attempt by the EEC to provide High-definition television (HDTV) in Europe. It is a complex mix of analogue signal, multiplexed with digital sound, and assistance data for decoding (DATV). The video signal was encoded with a modified D2-MAC encoder.
D-5 is a professional digital video format introduced by Panasonic at 18th International Television Symposium in Montreux in 1993 and released a year later in 1994. Like Sony's D-1 (8-bit), it is an uncompressed digital component system (10-bit), but uses the same half-inch tapes as Panasonic's digital composite D-3 format. A 120 min. D-3 tape will record 60 min. in D-5/D-5 HD mode. D-5 standard definition (SD) decks can be retrofitted to record high definition with the use of an external HD input/output box/decoder. There were native D5 HD decks as well that didn't need an external processor and could record in both SD and HD. High definition conversion on D5 HD decks does not allow for any error correction that exists on standard definition recordings, as the full bandwidth of the tape is required for high definition recording.
HDV is a format for recording of high-definition video on DV videocassette tape. The format was originally developed by JVC and supported by Sony, Canon, and Sharp. The four companies formed the HDV Consortium in September 2003.
720p is a progressive HD signal format with 720 horizontal lines/1280 columns and an aspect ratio (AR) of 16:9, normally known as widescreen HD (1.78:1). All major HD broadcasting standards include a 720p format, which has a resolution of 1280×720.
1080i is a term used in high-definition television (HDTV) and video display technology. It means a video mode with 1080 lines of vertical resolution. The "i" stands for interlaced scanning method. This format was once a standard in HDTV. It was particularly used for broadcast television. This is because it can deliver high-resolution images without needing excessive bandwidth. This format is used in the SMPTE 292M standard.
576p is the shorthand name for a video display resolution. The p stands for progressive scan, i.e. non-interlaced, the 576 for a vertical resolution of 576 pixels. Usually it corresponds to a digital video mode with a 4:3 anamorphic resolution of 720x576 and a frame rate of 25 frames per second (576p25), and thus using the same bandwidth and carrying the same amount of pixel data as 576i, but other resolutions and frame rates are possible.
HDCAM is a high-definition video digital recording videocassette version of Digital Betacam introduced in 1997 that uses an 8-bit discrete cosine transform (DCT) compressed 3:1:1 recording, in 1080i-compatible down-sampled resolution of 1440×1080, and adding 24p and 23.976 progressive segmented frame (PsF) modes to later models. The HDCAM codec uses rectangular pixels and as such the recorded 1440×1080 content is upsampled to 1920×1080 on playback. The recorded video bit rate is 144 Mbit/s. Audio is also similar, with four channels of AES3 20-bit, 48 kHz digital audio. Like Betacam, HDCAM tapes were produced in small and large cassette sizes; the small cassette uses the same form factor as the original Betamax. The main competitor to HDCAM was the DVCPRO HD format offered by Panasonic, which uses a similar compression scheme and bit rates ranging from 40 Mbit/s to 100 Mbit/s depending on frame rate.
1080p is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen vertically; the p stands for progressive scan, i.e. non-interlaced. The term usually assumes a widescreen aspect ratio of 16:9, implying a resolution of 2.1 megapixels. It is often marketed as Full HD or FHD, to contrast 1080p with 720p resolution screens. Although 1080p is sometimes referred to as 2K resolution, other sources differentiate between 1080p and (true) 2K resolution.
Progressive segmented Frame is a scheme designed to acquire, store, modify, and distribute progressive scan video using interlaced equipment.
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 that 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.
High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it refers to the generation following standard-definition television (SDTV). It is the standard video format used in most broadcasts: terrestrial broadcast television, cable television, satellite television.
4K resolution refers to a horizontal display resolution of approximately 4,000 pixels. Digital television and digital cinematography commonly use several different 4K resolutions. In television and consumer media, 3840 × 2160 with a 16:9 aspect ratio is the dominant 4K standard, whereas the movie projection industry uses 4096 × 2160.
...using the ultra-efficient VC-1 Advanced Profile codec.
Our 2.5 Mbps HD files are streamed in high-quality 720p resolution.
We use h.264 with a bitrate of 3.2 Mbps and 192 kbps audio
In order to be classed as "true" high definition, we encode in at least 1280x720 resolution, or 720p.
Hulu videos are streamed as Flash video files (FLV files). These files are encoded using the On2 Flash VP6 codec...
HD videos on Hulu are streamed at 1280 x 720 resolution.
Hulu currently supports four different streams including 480kbps, 700kbps, 1,000kbps (an H.264 encode that is not on On2 VP6) and 2.5Mbps.
...but settled on second-generation HD encodes with VC1AP
second-generation HD encodes ... at 2600kbps and 3800kbps
For best results, we recommend using H.264 (sometimes referred to as MP4) for the video codec and AAC (short for Advanced Audio Codec) for the audio codec.[ permanent dead link ]
640x480 for standard definition 4:3 video, 853x480 for widescreen DV, or 1920x1080 for high definition.[ permanent dead link ]
Use 2000 kbits/sec for standard definition 4:3 video, 3000 kbits/sec for widescreen DV, or 5000 kbits/sec for high definition footage.[ permanent dead link ]
You'll want to set the bit rate to 320 kbps and the sample rate to 44.100 kHz.[ permanent dead link ]
...all HD content is ... encoded with H.264 High Profile
HDX (1080p)
HDX (1080p) requires 4500 kbps