|
Progressive segmented Frame (PsF, sF, SF) is a scheme designed to acquire, store, modify, and distribute 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 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. In the world of standard definition video, which traditionally has been using interlaced scanning, it is also known as ''quasi-interlace'' or ''progressive recording''. == 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. 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 () scheme claim compatibility with interlaced processing and recording equipment, a dubious objective in my view."〔 William F. Schreiber, former Director of the Advanced Television Research Program at 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. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「progressive segmented frame」の詳細全文を読む スポンサード リンク
|