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Canon XL1 3CCD Camcorder User Manual

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Channels

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‐Mostaudiofromcomputersiseithermonowithasinglechannelorstereowithtwochannels.

‐Lowbitratesgenerallyusemonobecauseitrequiresfewerbits.Theindustryisevolvingtouse

multichannel(5.1and7.1)audiosupportaswell.

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Perceptualaudiocompression

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‐Mostmoderncodecsuseperceptualencodingtechniques:

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aninternalmodelofthehumanauditorysystemdeterminestheimportantpartsofanaudiosource

andspendstheavailablebitsonthoseparts.

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Compressionefficiency

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definedbyhowmanybitsarerequiredtoreachaparticularqualitylevel.

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Whenimprovingcompressionefficiency,youcanchoosetolowerthedataratewhilekeepingthe

qualitythesame,increasethequalitywhilekeepingthedataratethesame,orpickapointin

between.

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Typically,thehigherthedatarate,thesmallerthequalitydifferences.

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Authoringvideoforfuturecompression

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‐Onekeytohigh‐qualitycompressioniscreatingcontentthatcompresseswell.

‐Thereareavarietyoftechniquesfordoingthis:Youcanapplythesetechniquesduring

preproduction,production,orpost‐production.

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Preproduction:It’sbesttointroducetheideaofcompressionearlyinaproject,soallmembersof

theteamcanconsidertheimplications.

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Production

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