Progressive segmented frame: Difference between revisions

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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 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 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=https://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> or ''movie mode''.<ref name="WSS">{{cite web|url=http://stoneship.org.uk/~steve/palplus.html|title=All You Ever Wanted to Know About PALplus but were Afraid to Ask}}</ref> Other names for PsF used by electronic equipment manufacturers include ''progressive recording'' (Sony), ''progressive scan mode'' (Sony), ''progressive shutter mode'' (Sony), ''frame shutter mode'' (Sony), ''frame mode'' (Panasonic and Canon), ''Digital Cinema mode'' (Panasonic) and ''cinema mode'' (Canon).

The PsF technique is similar to [[Telecine#2:2 pulldown|2:2 pulldown]], which is widely used in 50&nbsp;Hz television systems to broadcast progressive material recorded at 25 frame/s, but is rarely used in 60&nbsp;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 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=https://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>

== History ==

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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.

== Similar technologies ==

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&nbsp;pulldown]].

===Sony's2:2 "Framepulldown shutter(TV mode"broadcast)===

The PsF technique is similar to [[Telecine#2:2 pulldown|2:2 pulldown]], which is widely used in 50&nbsp;Hz interlaced television systems to broadcast progressive material recorded at 25 frame/s, but is rarely used in 60&nbsp;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.

===PALplus Movie Mode (TV broadcast) ===

"Frame shutter mode" or "progressive shutter mode" is [[Sony]]'s [[trademark]]ed [[progressive scan]] [[charge-coupled device]] (CCD) mode for video cameras. This mode allows full-frame acquisition with conventional [[interlaced video|interlaced]] field output. It is conceptually identical to PsF, except PsF is used in high definition video, while "frame shutter mode" is used by Sony for its [[standard definition]] products.

[[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("Movie Mode).<ref name="WSS"/>

===Video recorders===

In frame shutter mode, a 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 signal, which is also compatible with traditional interlaced scanning systems.

InPsF is utilized in some [[DV]], [[HDV]] and [[AVCHD]] [[camcorder]]s for 25-frame/s and 30-frame/s progressive-scan recording. To shutterachieve modethis, athe 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 signal, which is also compatible with traditional interlaced scanning systems.

Sony used frame shutter mode, later renamed to ''progressive recording'', in several consumer products. For example, the DCR-HC96 [[camcorder]] is capable of shooting in 30p progressive mode; its European cousin, the DCR-HC96E, has matching 25p progressive mode.

TheThis is how Sony described the progressive recording mode in the operating guide for a 60&nbsp;Hz ("NTSC") Sony DCR-HC96 camcorder describes the progressive recording mode as follows:

{{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"/>}}

The booklet for the 50&nbsp;Hz ("PAL") Sony DSR-PD175P camcorder describes its progressive recording mode as follows:

{{quotation|'''Progressive Scan Mode'''<br/><br/>The 25p image captured by the sensor system is recorded as an interlaced signal by dividing each frame into two fields. This enables compatibility with current editing and monitoring equipment that only accept interlaced signals, while maintaining the quality of the 25p image.|<ref>{{cite web|url=http://www.sony.co.uk/biz/pdf/GeneratePDF.action?product=DSR-PD175P&site=biz_en_GB|title=DSR-PD175P: 1/3-inch 3 Exmor CMOS professional DVCAM camcorder}}</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&nbsp;pulldown]].

== Encoding of color information ==

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