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Canon XL1 3CCD Camcorder User Manual

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1.Monochrome:

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onlyluminance(brightness)matters.

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worksgreatforblack‐and‐whitemovies.

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Mostvideocodecsdon’thaveanexplicitgrayscalemode.

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2.Red,Green,Blue(rGB):

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ComputerscreensandtelevisionsarenativelyRGB—thescreenhasred,green,andbluephosphors

forCRTsandplanesforLCDs.

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Unefficientforvideocontent,soRGBcodecsaren’tusedforbroadcastvideodeliveryanymore.

However,RGBiswidelyusedforscreenrecordingsandmotiongraphics.

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3.Y’CbCr:

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Thesecodecsencodeluminanceandtwocolor‐differencechannels

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Becausetherearethreecolors,youcanconvertY’CbCrtoRGBfordisplay.

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Byseparatingoutthechromaandlumachannels,youcankeepthe

criticallumainformationatfullresolutionanduselessresolutionforthechromainformation.

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Greatlyreducesdatarateandprocessingrequirements.YoucanconvertRGBto

andfromY’CbCradequately,buttherearealwayssomecolorsthatareavailableinonemodebutnot

theother,andtherecanberoundingerrorsaspartoftheconversion.(Byworkingintoolsthatsupport

16‐bit‐per‐channelRGB,likeAdobeAfterEffects®software,yousignificantlyimprovethequalityof

thisconversion)

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COLOURDEPTHS 

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Definetheprecisionofthecolorsanddeterminehowmanygradationsofintensitythereare.

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Measuredinthenumberofbitsperchannel(bpc)

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Categories:

1.8‐bit(indexed)color(oftencalled8‐bitor256color)

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doesn’tworkwellforvideobecauseeventhesimplestscenesusemorethan256

colors.Theonlysignificantformatthatstillrequires8‐bitindexedcolorisGIF.

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