المعرفة

دقة 4K

(تم التحويل من 4K resolution)

دقة 4K 4K resolution، أو 4K، تشير إلى دقة الشاشة الأفقية بدرجة 4.000 پكسل.[1] يوجد عدة أنواع مختلفة من دقة 4K في مجالات التلفزيون الرقمي والتصوير السينمائي الرقمي. في التلفزيون والإعلام الاستهلاكي، التلفزيون فائق الدقة 4K أو UHD-1 هو معيار 4K السائد. في صناعة عرض الأفلام، مبادرات السينما الرقمية (DCI 4K) هي معيار 4K السائد.

عام 2015، ازدادت الحصة السوقية لتلفزيون 4K حيث انخفضت الأسعار بشكل كبير في عام 2014[2] و2015. بحلول 2020، من المتوقع أن يمتلك ما يزيد عن نصف الأسر الأمريكية تلفزيونات كابلية 4K ‏(2160p‏)[3]، الذي يعتبر معدل تبني سريع للغاية عن معدل تبني الدقة العالية (1080p).[4]

مقارنة دقة البث الشائع.

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تعريفات

هناك ثلاث معايير رئيسية لدقة 4K:

  • UHD-1، أو ultra-high-definition television (UHDTV), is the 4K standard for television and computer monitors. UHD-1 is also called 2160p[5][6] as it has a resolution of 3840 × 2160 (16:9, or approximately a 1.78:1 aspect ratio), which is twice the horizontal and twice the vertical resolution of 1080p, or three times the horizontal and vertical resolution of 720p.[5] UHD-1 is used in consumer television and other media, e.g. video games.
  • UW4K is the ultra-wide 4K standard, with a resolution of 3840 × 1600, and an aspect ratio of 12:5 (2.4:1, or 21.6:9) This resolution is most commonly used on Ultra HD Blu-ray discs, and PC gaming monitors.
  • DCI 4K الذي له دقة 4096 × 2160 پكسل (256:135, approximately a 1.9:1 aspect ratio). This standard is only used in the film and video production industry.[7] The DCI 4K standard has twice the horizontal and twice the vertical resolution of DCI 2K.

وقد يسوّق العديد من الصانعين منتجاتهم على أنها UHD 4K, or simply 4K, when the term 4K is traditionally reserved for the cinematic, DCI resolution.[6][8][9] This has the potential to cause confusion for consumers.[6]

YouTube and the television industry have adopted UHD-1 as their 4K standard.[10][11] اعتبارا من 2014, 4K content from major broadcasters remains limited.[12] On April 11, 2013, Bulb TV created by Canadian serial entrepreneur Evan Kosiner became the first broadcaster to provide a 4K linear channel and VOD content to cable and satellite companies in North America.[13][14][15][16] The channel is licensed by the Canadian Radio-Television and Telecommunications Commission to provide educational content.[17] However, 4K content is becoming more widely available online including on YouTube, Netflix and Amazon.[18][19] By 2013, some UHDTV models were available to general consumers in the range of US$600.[20][21] اعتبارا من 2015, prices on smaller computer and television panels had dropped below US$400.[22] DVB expects UHD-1 Phase 2 services to be introduced by broadcasters from 2017, with features such as High Dynamic Range (using HLG and PQ at 10 or 12 bits), Wide Color Gamut (BT. 2020/2100 colorimetry), and High Frame Rate (up to 120 Hz). [23]


التاريخ

 
سامسونگ UN105S9 105 بوصة، تلفزيون فائق الدقة 4K.


عارض الڤيديو المنزلي

 
A JVC "e-shift" (pixel shifting) projector results in 4K pixel resolution on the screen



البث

الدقة

الصيغة الجودة معدل عرض الشاشة پكسل
تلفزيون فائق الدقة 3840 × 2160 1.78:1 (16:9) 8,294,400
تلفزيون فائق العرض 3840 × 1600 2.4:1 (12:5) 6,144,000
مبادرات السينما الرقمية 4K (جودة أصلية) 4096 × 2160 1.90:1 (256:135) 8,847,360
DCI 4K (CinemaScope cropped) 4096 × 1714 2.39:1 (1024:429) 7,020,544
DCI 4K (flat cropped) 3996 × 2160 1.85:1 (999:540) 8,631,360


التلفزيون فائق الدقة

السينما الرقمية

كونسورتيوم مبادرات السينما الرقمية وضع دقة معيارية 4096 pixels × 2160 lines (8.8 megapixels, aspect ratio 256:135) for 4K movie projection. This is the native resolution for DCI-compliant 4K digital projectors and monitors; pixels are cropped from the top or sides depending on the aspect ratio of the content being projected. The DCI 4K standard has twice the horizontal and vertical resolution of DCI 2K, with four times as many pixels overall. DCI 4K does not conform to the 16:9 aspect ratio, so it is not a multiple of the 1080p display.

Streaming الڤيديو

التسجيل

انظر أيضاً: List of 4K video recording devices
 
Sony Handycam FDR-AX1


انظر أيضاً

المصادر

  1. ^ Goulekas, Karen (2001). Visual Effects in a Digital World. Morgan Kaufmann. p. 587. ISBN 9780080520711. 4K resolution: A general term referring to any digital image containing an X resolution of approximately 4000 pixels.
  2. ^ "First Quarter 2015 4K TV Growth Strong As Overall LCD TV Shipments Slow, IHS Says". IHS Inc. 8 June 2015. Retrieved November 24, 2015.
  3. ^ "The exploding 4K market: Nearly 50% of U.S homes to have UHD TVs by 2020 according to new study -" (in الإنجليزية الأمريكية). Retrieved 2017-11-25.
  4. ^ Mark Hoelzel (2 September 2014). "4K TV Shipments Are Ramping Up Much Faster Than HD TV Did In The Past". Business Insider. Retrieved November 24, 2015.
  5. ^ أ ب Thomas, Alexander. "Just how useful is 2160p aka 4K?".
  6. ^ أ ب ت "4K vs. UHD: What's the difference? – ExtremeTech".
  7. ^ Denison, Caleb (15 Jan 2014). "Your 1080p TV is old already: Everything you need to know about Ultra HD 4K". Digital Trends. Retrieved 31 May 2014.
  8. ^ "The Best TV Deserves The Best TV – Samsung". Samsung Electronics America.
  9. ^ "X Series – 4K TV : BRAVIA™ LED TV, Full HD Television, 4K TV, 3D TV : Sony India". Sony India.
  10. ^ "Leading Television Industry Players Line Up To Support '4K Ultra HD'" (Press release). Consumer Electronics Association. 11 November 2014. Retrieved 18 December 2014.
  11. ^ Lowensohn, Josh (9 July 2010). "YouTube now supports 4k-resolution videos". Tech Culture. CNET. Retrieved 18 December 2014.
  12. ^ Brown, Heather (16 October 2014). "Good Question: When Will We See Broadcasts In 4K?". Local. CBS Minnesota. Retrieved 18 December 2014.
  13. ^ "Canadian Serial Entrepreneur to Launch First 4,000-pixel Television Signal, Bulb TV". 11 April 2013. Retrieved 12 November 2013.
  14. ^ "Young media mogul granted TV licence". 12 April 2013. Archived from the original on 14 May 2013. Retrieved 12 November 2013. {{cite web}}: Unknown parameter |deadurl= ignored (|url-status= suggested) (help)
  15. ^ "Canadian Cat B Channel Plans 4K Video Feed". 16 April 2013. Retrieved 12 November 2013.
  16. ^ "Bulb TV to turn on 4k". 12 April 2013. Retrieved 12 November 2013.
  17. ^ "Broadcasting Decision CRTC 2012-268". 4 May 2012.
  18. ^ Luckerson, Victor (12 November 2014). "Amazon Will Stream in Ultra-High Def 4K by January". Tech Companies. Time. Retrieved 18 December 2014.
  19. ^ Anderson, Jim (17 December 2014). "4K Ultra HD, High Quality: Red". YouTube. Retrieved 18 December 2014..
  20. ^ Cox, Joe (27 June 2013). "Seiki launches 39in 4K TV for $699". What Hi-Fi. Haymarket. Retrieved 21 January 2014.
  21. ^ Greenwald, Will (28 June 2013). "Seiki SE39UY04". PC Mag. Ziff Davis. Retrieved 21 January 2014.
  22. ^ "Viewsonic monitor". Newegg.com. Retrieved 21 November 2015.
  23. ^ https://www.dvb.org/resources/public/factsheets/dvb_-_phasing_in_uhd.pdf

وصلات خارجية

مقالات


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المواقع الرسمية لـNHK

ڤيديو

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