Canon XL1 3CCD Camcorder User Manual


 
‐Preprocessingiscriticalforwebvideo,butgenerallyitisnotneededwhenyouconverttovideo
formatslikeMPEG2forDVDorSVCD.
Deinterlacingvideo
‐Themostbasicandcriticalformofpreprocessingforthewebisdeinterlacing.
‐Mostvideoisproducedandeditedasinterlaced(although,anincreasingamountisdoneas
progressivescan).Butalmostallwebvideoisencodedasprogressivescan.
‐Ifthesourceframeofvideoisleftwithinterlacedlinesintact,theoutputshowsthestackedlines.
‐So,atthesamebitrate,deinterlacedvideoshowsfewerartifactsthaninterlacedvideo.
Understandingtelecineandinversetelecine
‐Aspecialcaseofprogressivescanisfilmsourceandfilmlike24Pproduction.Traditional
motionpicturefilmrunsatexactly24framespersecond(fps)progressivescan,whichdoesn’tconvert
tothe59.94fpsofNTSCorthe50fpsofPAL.
‐ConvertingfromfilmtoPALiseasy.Thevideoisspedup4%to 25fpsandconvertedintoprogressive
PAL.
‐NTSCisalittlemorecomplextoperform.Thefilmisfirstsloweddownto23.976fps,andthenitis
convertedtothe59.94fpsbyusing3:2pulldown.
‐Thefirstframeoffilmbecomesthreefieldsofvideo,andthenextframebecomestwofieldsofvideo,
andthenextbecomesthreefields,andsoon.
‐Thisprocessresultsintwooutoffiveframeshavingfieldsthatcomefromdifferentsourceframes.
‐Whenpossible,itisbesttoconvertto24Ponimportandthendoalltheworkontheprojectin24P
mode.
Cropping
‐Thesafeareasexcludetheedgesofthescreen,whichmaybecutoffordistortedonsometelevisions
(especiallyolderones).
‐Insomedigitalvideoeditingapplications,youcancropanimageusingafilter.Inothers,suchas