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'''Progressive segmented Frame''' (PsF, sF, SF) is a scheme designed to acquire, store, modify, and distribute [[progressive scan|progressive-scan]] video using [[interlaced]] equipment and media.
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:
The term ''progressive segmented frame'' is used predominantly in relation to [[high-definition video|high definition]] video. In the world of [[standard definition]] video, which traditionally has been using interlaced scanning, it is also known as ''quasi-interlace''<ref name="POYNTON_DVANDHDTV_P62">{{cite book|url=http://books.google.com/books?id=ra1lcAwgvq4C&pg=RA1-PA62&sig=8ZAl0RqzUYnyxQSmjxiIw4ZJDbE|title=Charles Poynton, Digital Video and HDTV: Algorithms and Interfaces}}</ref> or ''progressive recording''.<ref name="DCR-HC36/HC46/HC96 OG PR">{{cite web|url=http://www.docs.sony.com/release/DCRHC36-46-96.pdf |title=DCR-HC36/HC46/HC96 Operating Guide |publisher=Sony Corporation |year=2006 |accessdate=2010-08-11}}</ref>
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== 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|url=http://www.tech-notes.tv/Jim/Articles/24vs48sF.html|title=Jim Mendrala, A discussion of 24p frame and the new 48sF frame format}}</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 existing interlaced equipment having to be modified for 48 Hz scanning rate in order to work properly with 24 frame/s content.
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>
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Despite the criticism, PsF quickly became a de facto standard for high quality film-to-video transfer. One of the documented examples of PsF usage is the 2003 transfer of the film "Terminator 2" to DVD, performed by Artisan and THX. The original 24 frame/s movie was converted to PsF format and recorded to [[D5 HD|HD-D5]] videotapes. This allowed for the creation of a digital master that was nearly identical to the original film, and made it possible to edit digitally at the native frame rate.<ref>{{cite web|url=http://www.dtvforum.info/lofiversion/index.php/t16581.html|title=Terminator 2: Extreme Edition}}</ref> The same digital master appears to be used for the 2006 [[Blu-ray Disc]] transfer of the movie.<ref>{{cite web|url=http://bluray.highdefdigest.com/terminator2.html|title=Terminator 2: Judgment Day (Blu-ray)}}</ref>
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: Attack of the Clones|Star Wars, Episode 2]], and by [[Alexander Sokurov]] for creating [[Russian Ark]] fully in the digital ___domain.
PsF is utilized in some [[DV]], [[HDV]] and [[AVCHD]] camcorders for 25-frame/s and 30-frame/s progressive-scan recording, and can be called ''Progressive recording'' (Sony), ''Progressive scan mode'' (Sony), ''Frame mode'' (Panasonic and Canon), ''Digital Cinema mode'' (Panasonic) or ''Cinema mode'' (Canon). Consumer and many 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]].
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}}</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 often recorded in interlaced format, despite that the content is progressive. This may result in interlaced artifacts being noticeable on colored objects.<ref>
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