High-definition video explained

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. 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.

History

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.

Analog

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.

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.

Digital

High-definition digital video was not possible with uncompressed video due to impractically high memory and bandwidth requirements, with a bit rate exceeding 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 that preclude the interoperability that was hoped for after decades of largely non-interoperable analog TV broadcasting.

Technical details

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[7] 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.

Common high-definition video modes

Video modeFrame size in pixels (W×H)Pixels per image1Scanning typeFrame rate (Hz)
720p (also known as HD Ready)1,280×720921,600Progressive23.976, 24, 25, 29.97, 30, 50, 59.94, 60, 72
1080i (also known as Full HD)1,920×1,0802,073,600Interlaced25 (50 fields/s), 29.97 (59.94 fields/s), 30 (60 fields/s)
1080p (also known as Full HD)1,920×1,0802,073,600Progressive24 (23.976), 25, 30 (29.97), 50, 60 (59.94)
1440p (also known as Quad HD)2,560×1,4403,686,400Progressive24 (23.976), 25, 30 (29.97), 50, 60 (59.94)

Ultra high-definition video modes

Video modeFrame size in pixels (W×H)Pixels per image1Scanning typeFrame rate (Hz)
20002,048×1,5363,145,728Progressive24, 30, 60
2160p (also known as 4K UHD)3,840×2,1608,294,400Progressive60, 120
2540p4,520×2,54011,480,800Progressive24, 30, 60
4000p4,096×3,07212,582,912Progressive24, 30, 60
4320p (also known as 8K UHD)7,680×4,32033,177,600Progressive60, 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.

HD content

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.

Types of recorded media

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.

See also: Telecine and Deinterlacing.

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.

HD in filmmaking

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). Note that resolution values for 70 mm film are higher than those listed above.

HD on the World Wide Web/HD streaming

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:

World Wide Web HD resolutions

SourceCodecHighest resolution (W×H)Total bit rate/bandwidthVideo bit rateAudio bit rate
Amazon Video[9] VC-1[10] 1280×720[11] 2.5-6 Mbit/s
BBC iPlayerH.264[12] 1280×720[13] [14] 3.2 Mbit/s3 Mbit/s192 kbit/s
blinkbox1280×7202.25 Mbit/s (SD) and 4.5 Mbit/s (HD)2.25 - 4.5 Mbit/s192 kbit/s
Blockbuster Online1280×720
CBS.com/TV.com1920×1080[15] 3.5 Mbit/s and 2.5 Mbits (720p)
DacastVP6, H.264[16] Unknown5 Mbit/s[17]
HuluOn2 Flash VP6[18] 1280×720[19] 2.5 Mbit/s[20]
iTunes/Apple TVQuickTime H.264[21] 1920×1080
MetaCDNMPEG-4, FLV, OGG, WebM, 3GP[22] No Limit[23]
NetflixVC-1[24] 3840×2160[25] 25 Mbit/s[26] 2.6 Mbit/s and 3.8 Mbit/s (1080p)[27]
PlayStation VideoH.264/MPEG-4 AVC[28] 1920×10808 Mbit/s256 kbit/s
VimeoH.264[29] 1920×1080[30] 4 Mbit/s[31] 320 kbit/s[32]
VuduH.264[33] 1920×1080[34] 4.5 Mbit/s[35]
Xbox Video[36] 1920×1080[37]
YouTubeH.264/MPEG-4 AVC, VP9, AV17680×4320

HD in video surveillance

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.[38]

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.[39] 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.

HD in video gaming

Both the PlayStation 3[40] the Xbox 360[41] 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. The Wii does not support HD.[42] In the 8th generation, Nintendo's Wii U[43] and Nintendo Switch,[44] Microsoft's Xbox One, and Sony's PlayStation 4 display games 1080p natively.[45] 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.[44] The Xbox One X and PlayStation 4 Pro can display some games in 4K.[45] The PlayStation 5 and Xbox Series X can display games in 4K and 8K.[46]

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.[47] Ultrawide monitors are supported, which can display more of the game world than a traditional display with a 16:9 aspect ratio,[48] and multi-monitor setups are possible, such as having a single game span across three monitors for a more immersive experience.[49]

See also

Further reading

External links

Notes and References

  1. Book: Lee . Jack . Scalable Continuous Media Streaming Systems: Architecture, Design, Analysis and Implementation . 2005 . . 9780470857649 . 25 .
  2. Shishikui . Yoshiaki . Nakanishi . Hiroshi . Imaizumi . Hiroyuki . An HDTV Coding Scheme using Adaptive-Dimension DCT . Signal Processing of HDTV: Proceedings of the International Workshop on HDTV '93, Ottawa, Canada . October 26–28, 1993 . 611–618 . 10.1016/B978-0-444-81844-7.50072-3 . . 9781483298511.
  3. Ahmed . Nasir . N. Ahmed . How I Came Up With the Discrete Cosine Transform . . January 1991 . 1 . 1 . 4–5 . 10.1016/1051-2004(91)90086-Z . 1991DSP.....1....4A .
  4. Book: Ghanbari . Mohammed . Standard Codecs: Image Compression to Advanced Video Coding . 2003 . . 9780852967102 . 1–2 .
  5. Book: Li . Jian Ping . Proceedings of the International Computer Conference 2006 on Wavelet Active Media Technology and Information Processing: Chongqing, China, 29-31 August 2006 . 2006 . . 9789812709998 . 847 .
  6. Book: Lea . William . Video on demand: Research Paper 94/68 . 1994 . . 20 September 2019 . https://web.archive.org/web/20190920082623/https://researchbriefings.parliament.uk/ResearchBriefing/Summary/RP94-68 . 20 September 2019 . dead .
  7. Web site: L_2021068EN.01010801.xml . 2023-03-19 . eur-lex.europa.eu.
  8. Web site: Why HD movie downloads are a big lie. 2007-05-31. 2010-06-28. Ziff-Davis.
  9. Formerly "Amazon Unbox", which now refers to a video player software, and later "Amazon Video on Demand".
  10. Web site: Amazon.com -- News Release. 2006-09-07. 2009-10-16. ...using the ultra-efficient VC-1 Advanced Profile codec..
  11. Web site: Amazon.com: Help > Digital Products > Amazon Video On Demand. Amazon. 2009-10-16. Our 2.5 Mbps HD files are streamed in high-quality 720p resolution..
  12. Web site: What do I need to know about HD on BBC iPlayer?. BBC. We use h.264 with a bitrate of 3.2 Mbps and 192 kbps audio. 2014-02-11. 2014-02-22. https://web.archive.org/web/20140222060217/http://iplayerhelp.external.bbc.co.uk/help/about_bbc_iplayer/hd_bbciplayer. dead.
  13. Web site: What do I need to know about HD on BBC iPlayer?. BBC. In order to be classed as "true" high definition, we encode in at least 1280x720 resolution, or 720p.. 2014-02-11. 2014-02-22. https://web.archive.org/web/20140222060217/http://iplayerhelp.external.bbc.co.uk/help/about_bbc_iplayer/hd_bbciplayer. dead.
  14. During live events "BBC iPlayer" streams have a resolution of 1024×576.
  15. Web site: CBS.com - HD Video - System Requirements. 2009-10-16. CBS.com.
  16. Web site: Streaming Protocols for Flash, RTMP, H.264 & VP6. 2011-11-30. Dacast.
  17. Web site: Live Streaming Solution. 2011-11-30. Dacast.
  18. Web site: Hulu - About. https://web.archive.org/web/20091026201922/http://www.hulu.com/about/media_faq#technology. dead. 2009-10-26. 2009-10-16. Hulu. Hulu videos are streamed as Flash video files (FLV files). These files are encoded using the On2 Flash VP6 codec....
  19. Web site: Hulu - About. https://web.archive.org/web/20091026201922/http://www.hulu.com/about/media_faq#technology. dead. 2009-10-26. 2009-10-16. Hulu. HD videos on Hulu are streamed at 1280 x 720 resolution..
  20. Web site: Hulu - About. https://web.archive.org/web/20091026201922/http://www.hulu.com/about/media_faq#technology. dead. 2009-10-26. 2009-10-16. Hulu. Hulu currently supports four different streams including 480kbps, 700kbps, 1,000kbps (an H.264 encode that is not on On2 VP6) and 2.5Mbps..
  21. Web site: Video quality reference table from best to worst.
  22. Web site: MetaCDN Technical Specs. 2014-08-20. MetaCDN. https://web.archive.org/web/20140820214117/http://www.metacdn.com/technical-specs.jsp. 2014-08-20. dead.
  23. Web site: Live Streaming Service. 2014-08-20. MetaCDN.
  24. Web site: The Official Netflix Blog: Encoding for streaming. 2008-11-06. 2009-10-16. Hunt. Neil. Netflix. ...but settled on second-generation HD encodes with VC1AP.
  25. News: You Can Now Stream 4K Netflix on Windows 10. MakeUseOf. 2016-11-26.
  26. Web site: Internet Connection Speed Recommendations. Help Center. 2016-11-26.
  27. Web site: The Official Netflix Blog: Encoding for streaming. 2008-11-06. 2009-10-16. Hunt. Neil. Netflix. second-generation HD encodes ... at 2600kbps and 3800kbps.
  28. Web site: Online Video Content Distribution: Sony's PlayStation 3 Enters The Ring (Albeit With A Sound-Hampered Hand Tied Behind Its Back). 2009-10-16. Dipert. Brian. 2008-07-17. EDN. https://web.archive.org/web/20080907104606/http://www.edn.com/blog/400000040/post/910030091.html. 2008-09-07. dead.
  29. Web site: Vimeo - Compression guidelines on Vimeo. 2009-10-16. Vimeo. 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..
  30. Web site: Vimeo - Compression guidelines on Vimeo. 2009-10-16. Vimeo. 640x480 for standard definition 4:3 video, 853x480 for widescreen DV, or 1920x1080 for high definition..
  31. Web site: Vimeo - Compression guidelines on Vimeo. 2009-10-16. Vimeo. Use 2000 kbits/sec for standard definition 4:3 video, 3000 kbits/sec for widescreen DV, or 5000 kbits/sec for high definition footage..
  32. Web site: Vimeo - Compression guidelines on Vimeo. 2009-10-16. Vimeo. You'll want to set the bit rate to 320 kbps and the sample rate to 44.100 kHz..
  33. Web site: Showdown: Apple TV vs. VUDU . 2009-11-05 . Sturgeon . Shane . 2008-02-21 . HDTV Magazine . ...all HD content is ... encoded with H.264 High Profile . dead . https://web.archive.org/web/20080512073251/http://hdtvmagazine.com/columns/2008/02/showdown_apple_tv_vs_vudu.php . 2008-05-12 .
  34. Web site: Streaming Requirements. 2010-02-09. Vudu. HDX (1080p). https://web.archive.org/web/20100129025409/http://speedtest.vudu.com/cdn1/. 2010-01-29. dead.
  35. Web site: Streaming Requirements. 2010-02-09. Vudu. HDX (1080p) requires 4500 kbps. https://web.archive.org/web/20100129025409/http://speedtest.vudu.com/cdn1/. 2010-01-29. dead.
  36. Formerly "Xbox Live Marketplace Video Store", but replaced by "Xbox Video" in 2012.
  37. Web site: XBox Video. https://web.archive.org/web/20121027001642/http://xbox.com/video. dead. 27 October 2012. Microsoft. 8 November 2012.
  38. Web site: High Megapixel Cameras – It's Not Just About Quality . 2020-01-28. SecurityMagazine.
  39. Web site: 3 Ways Multi-Sensor Cameras Alter the Video Surveillance Landscape . 15 June 2018 . 2018-06-15. SecurityInfoWatch.
  40. Web site: PlayStation 3 Technical Specifications. SCEA. January 14, 2008. https://web.archive.org/web/20080113173737/http://www.us.playstation.com/ps3/about/specs . January 13, 2008. dead.
  41. Web site: Microsoft prepares major update to Xbox Live. Reimer. Jeremy. Ars Technica. October 30, 2006. January 26, 2023.
  42. Web site: June 2011 . Iwata Asks: E3 2011 Special Edition . June 9, 2011 . . 7 . April 21, 2013 . https://archive.today/20130421032134/http://www.nintendo.co.uk/Iwata-Asks/Iwata-Asks-E3-2011-Special-Edition-Wii-U/E3-2011-Special-Edition-Wii-U/1-Looking-Beyond-Wii/1-Looking-Beyond-Wii-205181.html . live .
  43. Web site: Nintendo Wii U supports 1080p, CPU and GPU confirmed. Yin-Poole. Wesley. Eurogamer. June 5, 2012. January 26, 2023.
  44. Web site: Is Nintendo Switch 4K? An overview of resolution on the portable console. Wood. Rhys. TechRadar. March 8, 2022.
  45. Web site: 4K is the wrong target for Xbox One X and PS4 Pro. Byford. Sam. The Verge. June 20, 2017. January 26, 2023.
  46. Web site: PS5 vs Xbox Series X: which next-gen console should you buy?. Vjestica. Adam. TechRadar. January 19, 2023. January 26, 2023.
  47. Web site: Samsung promises big things with the first DisplayPort 2.1 8K ultrawide monitor. Dexter. Alan. PC Gamer. November 4, 2022. January 26, 2023.
  48. Web site: Are ultrawide monitors worth it?. Smith. Matt. PC World. July 12, 2021. January 26, 2023.
  49. Web site: How to set up three monitors for super ultrawide gaming . Castle. Katharine. Rock Paper Shotgun. March 1, 2018. January 26, 2023.