Content deleted Content added
m Fixing broken anchor: 2020-12-10 #Frame rate→Rec. 709#Frame rates |
m caps. grammar. |
||
Line 1:
{{Short description|Scheme to handle progressive scan video using interlaced equipment}}
'''Progressive segmented
With PsF, a progressive frame is divided into two ''segments'', with the odd lines in one segment and the even lines in the other segment. Technically, the segments are equivalent to interlaced ''fields'', but unlike native interlaced video, there is no motion between the two fields that make up the video frame: both fields represent the same instant in time. This technique allows for a progressive picture to be processed through the same electronic circuitry that is used to store, process and route interlaced video.
The term ''progressive segmented frame'' is used predominantly in relation to [[high-definition video|high definition]] video. In
== History ==
PsF was designed to simplify the conversion of cinematic content to different video standards, and as a means of video exchange between networks and broadcasters worldwide.<ref>{{cite web |last=Mendrala |first=Jim |date=December 5, 1998 |title=A discussion of 24p frame and the new 48sF frame format |url=http://www.tech-notes.tv/Jim/Articles/24vs48sF.html |website=Home page of James A. Mendrala}}</ref> Brought to life by the movie industry in the end of the 1990s, the original PsF specification was focused on 24 frame/s content resulting in
Not everyone welcomed the PsF standard, however. Some industry observers maintained that native 24p processing would have been a better and cleaner choice. [[Charles Poynton]], an authority in digital television, made the following remark in his book: "Proponents of [PsF] scheme claim compatibility with interlaced processing and recording equipment, a dubious objective in my view."<ref name="POYNTON_DVANDHDTV_P62"/> William F. Schreiber, former Director of the Advanced Television Research Program at [[Massachusetts Institute of Technology|MIT]], suspected that the continued advocacy of interlaced equipment originated from consumer electronics companies that were trying to get back the substantial investments they had made in obsolete technology.<ref>{{cite web|url=http://www.cinemasource.com/articles/hist_politics_dtv.pdf|title=The history and politics of DTV}}</ref>
== Usage ==
Despite the criticism, PsF quickly became a de facto standard for high
PsF has been recognized by [[Rec. 709#Frame rates|Recommendation ITU-R BT.709]] as a legitimate way to transport progressive frames within an interlaced system. 25PsF and 30PsF rates have been added to the specification in addition to the more established 24PsF. "Fractional" frame rates, having the above values divided by 1.001, are also permitted; the resulting 23.976PsF and 29.97PsF rates are used in 59.94 Hz systems. No change from 59.94 Hz systems to 60 Hz (although provided for and anticipated) has occurred, allowing display on analog NTSC color televisions and monitors after down-conversion and encoding.
PsF became a means of initial image acquisition in professional Sony video cameras. It is employed in [[HDCAM]] and [[XDCAM]] video cameras, including the HDW-F900 [[CineAlta]] camera which was used by [[George Lucas]] for creating [[Star Wars: Episode II – Attack of the Clones|Star Wars, Episode 2]], and by [[Alexander Sokurov]] for creating [[Russian Ark]] fully in the digital ___domain.
Line 22 ⟶ 23:
===2:2 pulldown (TV broadcast)===
[[Telecine#2:2 pulldown|2:2 pulldown]] is widely used in 50 Hz interlaced television systems to broadcast progressive material recorded at 25 frame/s, but is rarely used in 60 Hz systems. The 2:2 pulldown scheme had originally been designed for interlaced displays, so fine vertical details are usually filtered out to minimize ''[[interline twitter]]''. PsF has been designed
===PALplus film mode (TV broadcast) ===
Line 72 ⟶ 73:
== Variants ==
* '''24PsF''' (48sF, 1080sf24, 1920×1080/24/1:1SF) is the original PsF format, which is used in professional equipment for film-to-video transfer, for high definition mastering and for video exchange between networks. This may be the first universal video standard
* '''25PsF''' (1080sf25, 1920×1080/25/1:1SF) is used in 50 Hz systems for production that originates on video and is targeted for television distribution.
* '''29.97PsF''' (1080sf29, 1920×1080/29.97/1:1SF) formats are sometimes used in 60 Hz systems for sitcoms and music shows.<ref>{{cite web|url=http://www.avsforum.com/avs-vb/showthread.php?p=13998888#post13998888|title='Beside You in Time' by Nine Inch Nails was encoded as interlaced.|date=March 2005 }}</ref><ref>{{cite web |last=Deering |first=Kris |date=November 2008 |title=Sony BDP-S350 Blu-ray Player review |url=http://hometheatermag.com/discplayers/sony_bdp-s350_blu-ray_player/ |url-status=dead |archive-url=https://web.archive.org/web/20090219000355/https://www.hometheatermag.com/discplayers/sony_bdp-s350_blu-ray_player/ |website=Home Theatre|archive-date=2009-02-19 }}</ref> 29.97PsF as well as '''30PsF''' (30p, 1080sf30, 1920×1080/30/1:1SF) formats are gaining popularity as an acquisition format for Web video delivery, because most video hosting web sites cannot stream video with rates higher than 30 frame/s.
| |||