Canon XL1 3CCD Manual

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‐Preprocessingiscriticalforwebvideo,butgenerallyitisnotneededwhenyouconverttovideo

formatslikeMPEG‐2forDVDorSVCD.

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Deinterlacingvideo

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‐Themostbasicandcriticalformofpreprocessingforthewebisdeinterlacing.

‐Mostvideoisproducedandeditedasinterlaced(although,anincreasingamountisdoneas

progressivescan).Butalmostallwebvideoisencodedasprogressivescan.

‐Ifthesourceframeofvideoisleftwithinterlacedlinesintact,theoutputshowsthestackedlines.

‐So,atthesamebitrate,deinterlacedvideoshowsfewerartifactsthaninterlacedvideo.

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Understandingtelecineandinversetelecine

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‐Aspecialcaseofprogressivescanisfilmsourceandfilm‐like24Pproduction.–Traditional

motionpicturefilmrunsatexactly24framespersecond(fps)progressivescan,whichdoesn’tconvert

tothe59.94fpsofNTSCorthe50fpsofPAL.

‐ConvertingfromfilmtoPALiseasy.Thevideoisspedup4%to 25fpsandconvertedintoprogressive

PAL.

‐NTSCisalittlemorecomplextoperform.Thefilmisfirstsloweddownto23.976fps,andthenitis

convertedtothe59.94fpsbyusing3:2pulldown.

‐Thefirstframeoffilmbecomesthreefieldsofvideo,andthenextframebecomestwofieldsofvideo,

andthenextbecomesthreefields,andsoon.

‐Thisprocessresultsintwooutoffiveframeshavingfieldsthatcomefromdifferentsourceframes.

‐Whenpossible,itisbesttoconvertto24Ponimportandthendoalltheworkontheprojectin24P

mode.

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Cropping

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‐Thesafeareasexcludetheedgesofthescreen,whichmaybecutoffordistortedonsometelevisions

(especiallyolderones).

‐Insomedigitalvideoeditingapplications,youcancropanimageusingafilter.Inothers,suchas