Qhov Transcoding yog dab tsi
Sep 29, 2017
Transcoding yog qhov digital-to-digital conversion ntawm ib tug encoding rau lwm, xws li rau cov ntaub ntawv yeeb yam ntaub ntawv (xws li, PAL, SECAM, NTSC), audio files (eg, MP3, WAV), los yog cim cim (eg, UTF- 8, ISO / IEC 8859). Qhov no feem ntau yog ua rau thaum muaj qhov khoom ntaus phiaj xwm (los yog kev ua haujlwm) tsis txhawb rau hom ntawv los yog txwv tsis pub muaj peev xwm uas yuav tsum txo cov ntaub ntawv me me, lossis hloov cov ntaub ntawv tsis raug lossis tsis muaj tseeb rau cov qauv zoo dua lossis hom tshiab.
Hauv ntiaj teb no analog yees duab, transcoding yuav ua tau yog thaum cov ntaub ntawv raug tshawb, nrog rau kev nthuav tawm. Piv txwv, Cineon thiab DPX cov ntaub ntawv tau muab siv los ua hom txheej txheem rau digital xinesmas, tiam sis cov duab ntawm ob xuab moos yog 8 vib nas this (TB). Qhov loj loj tuaj yeem ua rau tus nqi thiab kev nyuaj ntawm kev ua yeeb yam ntaub ntawv. Txawm li cas los, transcoding rau hauv ib JPEG2000 lossless hom ntawv tau zoo compression dua li lwm cov lossless coding yees, thiab ntau zaus, JPEG2000 tau compress dluab rau ib nrab-loj.
Transcoding feem ntau yog ib txoj kev los xij, pib lub cev poob; Txawm li cas los, transcoding yuav poob txawm yog cov zis yog los ntawm kev tsis los cuam tshuam lossis tsis muaj kev sib txuas lus.Qhov txheej txheem ntawm transcoding mus rau ib hom ntawv lossyj introduces sib txawv ntawm qib poob, thaum transcoding los lossy los lossless los yog uncompressed yog technically lossless conversion vim tsis muaj ntaub ntawv ploj ; Txawm li cas los xij, tus txheej txheem yog irreversible thiab yog tus paub tseeb dua ua kev puas tsuaj.
Re-encoding / recoding
Yog tias ib tus neeg xav hloov cov ntaub ntawv hauv ib hom ntawv sib tawm (piv txwv, ua duab editing ntawm ib tus duab JPEG), ib qho yuav txiav txim rau nws, hloov nws, ces rov encode nws. Qhov no rov encoding ua rau cov cim poob; yog li no yog tias xav tau ib qho kev hloov dua tshiab, ib tug yuav tsum tau kos dua ib zaug xwb, thiab ua txhua yam ntawm cov ntaub ntawv, es tsis rov ua dua qhov qub ntxiv. Ib yam li ntawd, yog hais tias yuav tsum tau muab cov ntaub ntawv sau losyog tsim nyog, nws yuav tsum muab ncua kom txog rau thaum cov ntaub ntawv xaus, xws li tom qab kawm tiav.
Tsawg dua bitrate
Hloov yog ib txoj kev zoo ib yam li transcoding hauv cov ntaub ntawv uas tau muab teev rau qhov tsawg dua uas tsis hloov hloov video; e [2] qhov no tuaj yeem muaj qhov piv txwv hloov ua piv txwv, tab sis yuav siv tus zauv sib npaug zuj zus. Qhov no tso cai rau ib qho kom haum rau cov xov xwm me me rau hauv qhov chaw me me (piv txwv li, phim ib daim DVD mus rau Video CD), los yog dhau ib sab channel bandwidth.
Image scaling
Hloov cov duab me me ntawm daim duab yog hu ua transsizing, thiab yog siv cov lus hais sib txawv ntawm qhov kev daws teeb meem ntawm cov xov xwm. Ntawm lub cuab yeej txaus, cov duab scaling yuav ua tau rau ntawm kev ua si, tiam sis nws kuj tseem ua tau los ntawm rov encoding, tshwj xeeb tshaj yog ib feem ntawm kev sib hloov (xws li ib cov duab downsampled kheej dua ib qho bitrate).
Ib tug tseem siv tau cov ntawv nrog bitrate peeling, uas cia ib tug yooj yim txo tus bitrate tsis rov encoding, tab sis zoo feem ntau qis tshaj ib rov encode. Piv txwv, nyob rau hauv Vorbis bitrate peeling raws li ntawm 2008, qhov zoo yog tsis zoo dua rau rov encoding.
