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'''Progressive segmented frame''' (PsF, sF, SF) is a scheme designed to acquire, store, modify, and distribute [[progressive scan]] video using [[interlaced]] equipment.
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.▼
▲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 PsF technique is similar to [[Telecine#2:2_pulldown|2:2 pulldown]], which is widely used in 50 Hz 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 for transporting progressive content and therefore does not employ such filtering.▼
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 |
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.
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
== Similar technologies ==
===2:2 pulldown (TV broadcast)===
The operating guide for a 60 Hz ("NTSC") Sony DCR-HC96 camcorder describes the progressive recording mode as follows:▼
▲
===PALplus film mode (TV broadcast) ===
{{quotation|'''Note on the progressive recording mode'''<br/><br/>In a normal TV broadcast, the screen is divided into 2 finer fields and these are displayed in turn, every 1/60 of a second. Thus, the actual picture displayed in an instant covers only half of the apparent picture area. In progressive recording, the picture is fully displayed with all the pixels.|<ref name="DCR-HC36/HC46/HC96 OG PR"/>}}▼
[[PALplus]] utilizes a digital stream embedded in the interlaced [[analog TV]] signal called [[widescreen signaling]], which, among other data, describes whether the signal should be treated as interlaced ("camera mode") or progressive ("film mode").<ref name="WSS"/>
===Video recorders===
<!-- Deleted image removed: [[File:Sony-PSF-workflow.jpg|thumb|300px|right|Video capture, edit and delivery workflow using progressive segmented frame technique (Sony)]] -->
PsF is utilized in some [[DV (video format)|DV]], [[HDV]] and [[AVCHD]] [[camcorder]]s for 25-frame/s and 30-frame/s progressive-scan recording. To achieve this, the camera acquires 30 ([[NTSC]]) or 25 ([[PAL]]) independent images per second. These images are output as 60 (NTSC) or 50 (PAL) interlaced fields. The result is a progressive-scan content, which is compatible with traditional interlaced scanning systems.
This is how Sony described the progressive recording mode in the operating guide for a 60 Hz ("NTSC") Sony DCR-HC96 camcorder:
▲{{quotation|'''Note on the progressive recording mode'''
The booklet for the 50 Hz ("PAL") Sony DSR-PD175P camcorder describes its progressive recording mode as follows:
{{quotation|'''Progressive Scan Mode'''
▲The operating
{{quotation|'''Pro-Cinema function'''<br/>In addition to the effects when the Wide function is used, images can also be recorded at a rate of 30 frames a second with a strobe-like effect.<ref>{{cite web|url=http://ftp.panasonic.com/camcorder/om/pv-gs500_mul_om.pdf|title=Panasonic PV-GS500: operating instructions}}</ref>}}
The HDV Progressive Primer whitepaper mentions Progressive Segmented Frame mode:
{{quotation|'''Progressive Scan Mode'''<br/>In this mode, the captured image is divided into two halves, then recorded or output as interlace signal. The halves are called segments, not fields, because there is no temporal difference between them. This method is also called as PsF (Progressive segmented Frame) recording. The Progressive Scan mode is suitable for the feature films, documentaries, music videos which have to be recorded as interlaced video for viewing on interlaced monitors, but want to offer “progressive-look” to their motion. Besides, the video taken in the Progressive Scan mode can be edited and output as true progressive video if needed.<ref>{{cite book | title = HDV Progressive Primer | publisher = Sony | page = 11 | url = http://www.sony-asia.com/microsite/professional/hdv/pdf/HDV_Progressive_Primer.pdf}}</ref>}}
Consumer camcorders as well as most professional camcorders do not use PsF to record 24-frame/s video; instead they either record it natively in progressive form or apply [[Telecine#23pulldown|2:3 pulldown]].
Most video formats including professional ones utilize [[chroma subsampling]] to reduce amount of [[Chrominance|chroma]] information in a video, taking advantage of the human visual system's lower acuity for color differences than for luminance.<ref>
{{cite book
Line 41 ⟶ 61:
| isbn = 978-0-7923-7422-0
| page = 209
| chapter-url =
}}</ref> Such a reduction improves compression of the video signal, which is always desirable because of storage and transmission limitations. To ensure compatibility with interlaced-based systems, chroma information in PsF video is sometimes recorded in interlaced format, despite that the content is progressive. This may result in [[Chroma subsampling#Interlaced and progressive|interlaced artifacts]] being noticeable on colored objects.<ref>
{{cite web
| title = Review: Canon Vixia HF11 AVCHD camcorder
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| publisher = ProVideo Coalition
| date = 2009-01-12
| url =
}}</ref>
== Variants ==
* '''24PsF''' (48sF, 1080sf24,
* '''25PsF''' (1080sf25,
* '''29.97PsF''' (1080sf29,
▲* '''25PsF''' (1080sf25, 1920x1080/25/1:1SF) is used in 50 Hz systems for production that originates on video and is targeted for television distribution.
▲* '''29.97PsF''' (1080sf29, 1920x1080/29.97/1:1SF) 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.}}</ref><ref>{{cite web|url=http://hometheatermag.com/discplayers/sony_bdp-s350_blu-ray_player/|title=Sony BDP-S350 Blu-ray Player review}}</ref> 29.97PsF as well as '''30PsF''' (30p, 1080sf30, 1920x1080/30/1:1SF) 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.
==References==
{{Reflist|30em}}
{{DEFAULTSORT:Progressive Segmented Frame}}
[[Category:Film and video technology]]
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