720p: Difference between revisions
→Resolutions: Never heard of that resolution or aspect being used for HDTV, and I've been messing with this stuff a LONG time. Plus Rec601 doesn't define anything re: hi-def, certainly not a 3:2, 1080x720 rez. It's not in the linked article either. |
Technically correct but felt it needed a better explanation, with a basis in more than just overly exacting number-pedantry. Besides, 60.00hz is an entirely valid broadcast rate, and the highest ATSC rate available, 0.1% faster than 59.94005994(...)hz ;-) |
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'''720p''' (1280×720 [[Pixel|px]]; also called '''[[HD Ready]]''' or standard HD) is a progressive [[High-definition television|HDTV]] signal format with 720 horizontal lines and an [[aspect ratio]] (AR) of [[16:9]], normally known as widescreen HDTV (1.78:1). All major HDTV broadcasting standards (such as [[SMPTE 292M]]) include a 720p format which has a resolution of 1280×720; however, there are other formats, including [[HDV]] Playback and [[AVCHD]] for camcorders, which use 720p images with the standard HDTV resolution. The [[frame rate]] is standards-dependent, and for conventional broadcasting appears in 50 progressive frames per second in former PAL/SECAM countries (Europe, Australia, others), and 59.94 frames per second in former NTSC countries (North America, Japan, Brazil, others). |
'''720p''' (1280×720 [[Pixel|px]]; also called '''[[HD Ready]]''' or standard HD) is a progressive [[High-definition television|HDTV]] signal format with 720 horizontal lines and an [[aspect ratio]] (AR) of [[16:9]], normally known as widescreen HDTV (1.78:1). All major HDTV broadcasting standards (such as [[SMPTE 292M]]) include a 720p format which has a resolution of 1280×720; however, there are other formats, including [[HDV]] Playback and [[AVCHD]] for camcorders, which use 720p images with the standard HDTV resolution. The [[frame rate]] is standards-dependent, and for conventional broadcasting appears in 50 progressive frames per second in former PAL/SECAM countries (Europe, Australia, others), and 59.94 frames per second in former NTSC countries (North America, Japan, Brazil, others). |
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The number ''720'' stands for the 720 horizontal [[scan line]]s of image [[display resolution]] (also known as 720 pixels of vertical resolution).<ref>{{Cite web |url=http://www.afterdawn.com/glossary/term.cfm/720p |title=720p - AfterDawn: Glossary of technology terms & acronyms}}</ref> The ''p'' stands for [[progressive scan]], i.e. non-interlaced. When broadcast at 60{{refn|It is |
The number ''720'' stands for the 720 horizontal [[scan line]]s of image [[display resolution]] (also known as 720 pixels of vertical resolution).<ref>{{Cite web |url=http://www.afterdawn.com/glossary/term.cfm/720p |title=720p - AfterDawn: Glossary of technology terms & acronyms}}</ref> The ''p'' stands for [[progressive scan]], i.e. non-interlaced. When broadcast at 60.00 frames/s{{refn|It is however more commonly broadcast at (60/1.001), or precisely 59.{{overline|940059}} frames/sec, matching the NTSC SDTV field rate; this and the 50.00hz of PAL are still the second and third highest standard framerates.<ref>{{Cite web |url= http://www.tvtechnology.com/article/60026 |title=Will the End of NTSC Be the End of 59.94? |publisher=TVTechnology |date=2008-01-09 |accessdate=2010-10-08 |first=Randy |last=Hoffner}}</ref>|group=note}} frames per second, 720p features the highest [[temporal resolution]] possible under the [[ATSC (standards)|ATSC]] and [[Digital Video Broadcasting|DVB]] standards. The term assumes a [[widescreen]] [[Aspect ratio (image)|aspect ratio]] of [[16:9]], thus implying a resolution of 1280×720 [[pixel|px]] (0.9 [[Pixel#Megapixel|megapixels]]). |
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720i (720 lines [[Interlaced video|interlaced]]) is an erroneous term found in numerous sources and publications. Typically, it is a typographical error in which the author is referring to the 720p HDTV format. However, in some cases it is incorrectly presented as an actual alternative format to 720p.<ref>{{cite book |title=HDTV for Dummies |last=Briere |first=Daniel |author2=Patrick Hurley |year=2006 |page=13 |url=https://books.google.com/books?id=Jb62Hkrj0oYC&printsec=frontcover&dq=hdtv+for+dummies |publisher=[[For Dummies]]}}</ref> No proposed or existing broadcast standard permits 720 ''interlaced'' lines in a video frame at any frame rate.<ref>{{cite web|format=PDF |url=http://www.atsc.org/cms/standards/a72/a_72_part_1.pdf |title=ATSC Standard: Video System Characteristics of AVC in the ATSC Digital Television System |date=2008-07-29 |accessdate=2011-07-24 |deadurl=yes |archiveurl=https://web.archive.org/web/20121004122811/http://www.atsc.org/cms/standards/a72/a_72_part_1.pdf |archivedate=2012-10-04 |df= }}</ref> |
720i (720 lines [[Interlaced video|interlaced]]) is an erroneous term found in numerous sources and publications. Typically, it is a typographical error in which the author is referring to the 720p HDTV format. However, in some cases it is incorrectly presented as an actual alternative format to 720p.<ref>{{cite book |title=HDTV for Dummies |last=Briere |first=Daniel |author2=Patrick Hurley |year=2006 |page=13 |url=https://books.google.com/books?id=Jb62Hkrj0oYC&printsec=frontcover&dq=hdtv+for+dummies |publisher=[[For Dummies]]}}</ref> No proposed or existing broadcast standard permits 720 ''interlaced'' lines in a video frame at any frame rate.<ref>{{cite web|format=PDF |url=http://www.atsc.org/cms/standards/a72/a_72_part_1.pdf |title=ATSC Standard: Video System Characteristics of AVC in the ATSC Digital Television System |date=2008-07-29 |accessdate=2011-07-24 |deadurl=yes |archiveurl=https://web.archive.org/web/20121004122811/http://www.atsc.org/cms/standards/a72/a_72_part_1.pdf |archivedate=2012-10-04 |df= }}</ref> |
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Revision as of 01:36, 24 January 2018
720p (1280×720 px; also called HD Ready or standard HD) is a progressive HDTV signal format with 720 horizontal lines and an aspect ratio (AR) of 16:9, normally known as widescreen HDTV (1.78:1). All major HDTV broadcasting standards (such as SMPTE 292M) include a 720p format which has a resolution of 1280×720; however, there are other formats, including HDV Playback and AVCHD for camcorders, which use 720p images with the standard HDTV resolution. The frame rate is standards-dependent, and for conventional broadcasting appears in 50 progressive frames per second in former PAL/SECAM countries (Europe, Australia, others), and 59.94 frames per second in former NTSC countries (North America, Japan, Brazil, others).
The number 720 stands for the 720 horizontal scan lines of image display resolution (also known as 720 pixels of vertical resolution).[1] The p stands for progressive scan, i.e. non-interlaced. When broadcast at 60.00 frames/s[note 1] frames per second, 720p features the highest temporal resolution possible under the ATSC and DVB standards. The term assumes a widescreen aspect ratio of 16:9, thus implying a resolution of 1280×720 px (0.9 megapixels).
720i (720 lines interlaced) is an erroneous term found in numerous sources and publications. Typically, it is a typographical error in which the author is referring to the 720p HDTV format. However, in some cases it is incorrectly presented as an actual alternative format to 720p.[3] No proposed or existing broadcast standard permits 720 interlaced lines in a video frame at any frame rate.[4]
Comparison with 1080i
Progressive scanning reduces the need to prevent flicker by anti-aliasing single high contrast horizontal lines.[5][6] It is also easier to perform high-quality 50↔60 Hz conversion and slow-motion clips with progressive video.
A 720p60 (720p at 59.94 Hz) video has advantage over 480i and 1080i60 (29.97/30 frame/s, 59.94/60 Hz) in that it comparably reduces the number of 3:2 artifacts introduced during transfer from 24 frame/s film. However, 576i and 1080i50 (25 frame/s, 50 Hz), which are common in Europe, generally do not suffer from pull down artifacts as film frames are simply played at 25 frames and the audio pitch corrected by 25/24ths. As a result, 720p60 is used for U.S. broadcasts while European HD broadcasts often use 1080i50 24* frame, with a horizontal resolution of 1920 or 1440 depending on bandwidth constraints. However, some European broadcasters do use the 720p50 format, such as German broadcasters ARD and ZDF, the Flemish Broadcasting Company (VRT) in Belgium, the Norwegian Broadcasting Corporation (NRK) and Spanish Radio and Television Corporation (TVE HD). Arte, a dual-language French-German channel produced in collaboration by ARD, ZDF and France Télévisions, broadcasts in German at 720p50 but in French at 1080i50.
Resolutions
| Standard | Resolution | Aspect Ratio |
|---|---|---|
| 720p Widescreen | 1280x720 | 16:9 |
| Standard TV 720p | 960×720 | 4:3 |
Notes
See also
References
- ^ "720p - AfterDawn: Glossary of technology terms & acronyms".
- ^ Hoffner, Randy (2008-01-09). "Will the End of NTSC Be the End of 59.94?". TVTechnology. Retrieved 2010-10-08.
- ^ Briere, Daniel; Patrick Hurley (2006). HDTV for Dummies. For Dummies. p. 13.
- ^ "ATSC Standard: Video System Characteristics of AVC in the ATSC Digital Television System" (PDF). 2008-07-29. Archived from the original (PDF) on 2012-10-04. Retrieved 2011-07-24.
{{cite web}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help) - ^ "720p". AfterDawn. 2010-08-10. Retrieved 2010-10-08.
- ^ "720p". CNET Glossary. Archived from the original on 2010-09-30. Retrieved 2010-10-08.
{{cite web}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help)