Editing HDV (section)

=== HDV 1080i {{anchor|HDV 1080i}} ===
[[File:Interlaced video frame (car wheel).jpg|thumb|250px|When interlaced video is watched on a progressive monitor without proper [[deinterlacing]], it exhibits combing when there is movement between two fields of one frame.]]
Sony adapted HDV, originally conceived as progressive-scan format by JVC, to interlaced video. Interlaced video has been a useful compromise for decades due to its ability to display motion smoothly while reducing recording and transmission bandwidth. Interlaced video is still being used in acquisition and broadcast, but interlaced display devices are being phased out. Modern [[Flat panel display|flat-panel]] television sets that utilize [[Plasma Display|plasma]] and [[Liquid crystal display|LCD]] technology are inherently progressive. All modern computer monitors use progressive scanning as well. 

Before interlaced video is displayed on a progressive-scan device it must be converted to progressive using the process known as [[deinterlacing]]. Progressive-scan television sets employ built-in deinterlacing circuits to cope with interlaced broadcast signal, but computer video players rarely have this capability (especially modern ones, since progressive video is much more common these days). As such, interlaced video may exhibit ghosting or combing artifacts when watched on a computer.

Some HDV&nbsp;1080i camcorders are capable of recording progressive video within an interlaced stream, provided that the frame rate does not exceed half of the [[Rec. 709#Frame rates|field rate]]. The first HDV 1080i camcorder to implement such ''Progressive Scanning'' was the Sony HVR-V1.<ref>{{cite web |url=http://www.camcorderinfo.com/content/Sony-Introduces-HVR-V1U-and-HDD-Unit-in-US.htm |title=Camcorderinfo.com: Sony Introduces HVR-V1U and HDD Unit in the U.S. |url-status=dead |archive-url=https://archive.today/20120720221609/http://www.camcorderinfo.com/content/Sony-Introduces-HVR-V1U-and-HDD-Unit-in-US.htm |archive-date=2012-07-20 }}</ref> To preserve compatibility with interlaced equipment the HVR-V1 records and outputs video in interlaced form. 25-frame/s and 30-frame/s progressive video is recorded on tape using [[progressive segmented frame]] (PsF) technique, while 24-frame/s recording employs [[Telecine#3:2 pulldown .28technically.2C 2:3 pulldown.29|2-3 pulldown]]. The camcorder offers two variations of 24-frame/s recording: "24" and "24A". In "24" mode the camera ensures that there are no cadence breaks for a whole tape, this mode works better for watching video directly from the camera and for adding "film look" to interlaced video. In the "24A" mode the camera starts every clip on an A frame with timecode set to an even second margin<ref>{{cite web|url=http://www.dv.com/reviews/reviews_item.php?articleId=196602843|title=dv.com: Sony HVR-V1 review}}</ref><ref>{{cite web|url=http://www.dvinfo.net/conf/sony-hvr-v1-hdr-fx7/82350-explained-24-verses-24a.html|title=DVInfo: EXPLAINED: "24" versus "24A"|url-status=dead|archive-url=https://archive.today/20120803113147/http://www.dvinfo.net/conf/sony-hvr-v1-hdr-fx7/82350-explained-24-verses-24a.html|archive-date=2012-08-03}}</ref> and records the 2-3 pull-down identification data in the HDV stream, so that compatible NLE software knows when to remove the 2-3 pull-down cadences.<ref>{{cite web|url=https://pro.sony.com/bbsccms/ext/hdv/z7u_s270u_m35u/HVR-Z7U/ft04.html|title=HDV 24p/30p Progressive Scan Modes}}</ref> Several editing tools, including Sony's own [[Sony Vegas|Vegas]], are capable of processing 24A video as proper 24 frame/s progressive video.<ref>{{cite web|url=http://www.digitalcontentproducer.com/hdhdv/depth/hdvatwork_sony_hvrv1u_031207|title=Steve Mullen, Reviewing Sony HVR-V1U HDV Camcorder}}</ref>

Prior to the HVR-V1, Sony was offering ''Cineframe'', essentially an interlaced-to-progressive converter, to simulate film-like motion. The conversion process involved blending and discarding fields, so vertical resolution of the resulting video suffered. Motion, produced in the 24-frame/s variant of Cineframe was too uneven for professional use.<ref>{{cite web|url=http://www.adamwilt.com/HDV/cineframe.html|title=Adam Wilt, How the Sony HDV cameras fake 24, 25, and 30 frame/s}}</ref> The same or better [[film look]] effect can be achieved by converting regular interlaced video into progressive format using computer software.<ref>{{cite web|url=http://www.hdtvexpert.com/pages_b/hdrfx1.html|title=Steve Mullen, Sony's HDR-FX1 1080i HDV Camcorder: using CineFrame 24 mode|access-date=2008-09-17|archive-url=https://web.archive.org/web/20081006001925/http://www.hdtvexpert.com/pages_b/hdrfx1.html|archive-date=2008-10-06|url-status=dead}}</ref>

In 2007 Canon commoditized progressive scanning, releasing the [[Canon HV20|HV20]] camcorder. The version for 50&nbsp;Hz market featured PF25 mode with PsF-like recording, while the version for 60&nbsp;Hz market had PF24 mode, which utilized 2-3 pulldown scheme. Progressive scan video recorded with the HV20 does not include flags necessary for performing automated film-mode deinterlacing, which is why most editing tools treat such video as interlaced.<ref>{{cite web|url=http://www.hv20.com/showpost.php?p=138512&postcount=23|title=Sony Vegas Movie Studio Platinum 9.0: no more pulldown hassle?}}</ref> The [[Canon HV30|HV30]], released in 2008, implemented additional PsF-like PF30 mode for 60&nbsp;Hz markets. Output is performed via component, HDMI and [[FireWire]] in interlaced form.<ref name="canonpmodes">{{cite web|url=http://www.avchduser.com/articles/canon_progressive_modes.jsp|title=Canon 24P, 25F, 25P, 30F, 30P modes explained|access-date=2008-09-04|archive-url=https://web.archive.org/web/20081212012956/http://www.avchduser.com/articles/canon_progressive_modes.jsp|archive-date=2008-12-12|url-status=usurped}}</ref>

Progressive scan video must be properly deinterlaced to achieve full vertical resolution and to avoid interlace artifacts. 25P and 30P video must be deinterlaced with "weave" or "no [[deinterlacing]]" algorithm, which means joining two fields of each frame together into one progressive frame. This operation can be done in most editing tools simply by changing project properties from interlaced to progressive. 24P video must go through ''film-mode deinterlacing'' also known as [[Telecine#Reverse_telecine_.28a.k.a._IVTC.2Finverse_telecine.29|inverse telecine]], which throws out [[Telecine#Telecine_judder|judder frames]] and restores original 24-frame/s progressive video. Many editing tools cannot perform film-mode deinterlacing, requiring usage of a separate converter.