Progressive segmented frame: Difference between revisions

Revision as of 20:01, 16 January 2008

Revision as of 20:13, 16 January 2008

Line 3:

== History ==

Originally, PsF was not meant neither for [[High-definition_television|broadcast]] nor for usage in home video devices. PsF was designed as a standard to simplify the conversion of cinematic content to different video standards, and as means forof 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 1990-ies, the original PsF specification was focused on 24 fps content. Existing interlaced equipment had to be modified for 48i scanning rate in order to work properly with PsF video.

With PsF, a progressive frame is sliced into two "segments", with the odd lines in one segment and the even lines in the other segment. This allows for a progressive picture to be processed through the same common electronic circuitry that is used to store, process and route interlaced video. Technically, progressive segments are equivalent to interlaced fields, but unlike native interlaced video, there is no motion between the two segments that make up the video frame. Both fields represent the same instant in time.

PsF allows the progressive format to be maintained, while minimizing bandwidth requirements using interlaced equipment. When translated to TV rates (either at 2:3 or 2:2 pulldown), the progressive image has a closer temporal match to the original film than is possible with a true interlace system, particularly now that modern displays (LCD & plasma) are natively progressive scan devices.<ref>{{cite web|url=http://www.pro-bel.com/site_documents/Vistek_HD_Poster.pdf|title=ro bel, Vistek HD Poster}}</ref>

Not everyone welcomed the PsF standard. Some industry observers maintained that native 24p processing would have been a better and cleaner choice. Others accused Sony Pictures in lobbying products of its parent company, Sony Corporation, which at that time was producing interlaced equipment. Charles Poynton, an authority in digital television, makes 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>{{cite web|url=http://books.google.com/books?id=ra1lcAwgvq4C&pg=RA1-PA62&sig=8ZAl0RqzUYnyxQSmjxiIw4ZJDbE|title=Charles Poynton, "Digital Video and HDTV: Algorithms and Interfaces"}}</ref>

Not everyone welcomed the PsF standard. Some industry observers maintained that native 24p processing would have been a better and cleaner choice. Others accused Sony Pictures in lobbying products of its parent company, Sony Corporation, which at that time was producing interlaced equipment. Charles Poynton, an authority in digital television, makes 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>{{cite web|url=http://books.google.com/books?id=ra1lcAwgvq4C&pg=RA1-PA62&sig=8ZAl0RqzUYnyxQSmjxiIw4ZJDbE|title=Charles Poynton, "Digital Video and HDTV: Algorithms and Interfaces"}}</ref>

PsF technology is implemented in [[HDCAM]] and [[XDCAM]] video cameras, including famous [[CineAlta]] camera that was used by George Lucas for the [[Star_Wars_Episode_II:_Attack_of_the_Clones|Star Wars, Episode 2]] movie.