Yai, ndipo ndi chinthu chimodzi chofunikira kudziwa za mtundu. Kawirikawiri, kupulumutsa kumayendetsanso kuwonongeka kwa encoder pazithunzi zomwe zakhala zikuyenda, motero zigawo za artefacts - zomwe zimawoneka ngati zoletsa m'mawu ndi haloes pazovuta zazikulu pambuyo pa zaka zambiri. Sinthani kuchokera ku master yopanda kusowa ndi kutumiza ku JPEG kamodzi, pamapeto pake, kuposa kutsegulanso ndikubwezeretsanso fayilo yomweyo. Bitstream ndi yofanana ndi.jpg: DCT-ochokera lossy kusamvana, nthawi zambiri ndi 4:2:0 chroma subsampling, wopangidwa mu JFIF kapena Exif header.
Nchifukwa chiyani kamera iliyonse ndi foni imandipatsa JPEG?
+
Chifukwa chake ndi mtundu womwe wonse wa photographic chain unali zaka zambiri zapitazo, ndipo palibe chomwe chimachokera pangozi ya kugwirizana kwa wopanga kamera. Ma data a sensor amachitidwa ndikusinthidwa mu kamerayo, pa sewero labwino lokhala ndi menyu, ndipo zomwe zimalandiridwa pakhadi ndi zithunzi zomaliza. Izi ndichifukwa chake kusintha kwachiwiri kwa chithunzi si nthawi zonse chimayambitsa anthu omwe amaganizira za - chimayambitsa choyamba, m'nyumba ya kamera. JPEG ndi standard yofanana ndi JPG ndi JFIF - the four-alemba kuwonjezeka ndi oyambirira, ndi the three-alemba mmodzi ali kokha chifukwa cha DOS 8.3 filename malire.
Kodi JPEG ndi mtundu umodzi monga momwe zimakhalira?
+
Yes.
Kodi ndiyenera kugwiritsa ntchito mtundu wotani posintha ku JPEG?
+
M'malo pakati pa 80 ndi 90 kwa chilichonse munthu adzaona. pansi pa 75 za artefacts ayamba kusonyeza pa khungu, kuwala ndi iliyonse lalikulu flat area; pamwamba 95 fayilo amakula mofulumira pamene pafupifupi palibe amene angaone kusiyana. kukhazikitsa si khalidwe la chithunzi, ndi lamulo la za izi padera kutumiza — choncho kusankha izo kwa kumene fayilo ndi kupita, ndi kusamalira oyambirira kwa nthawi ina inu mukufuna yankho lina.
Nchifukwa chiyani kumbuyo kwakuwonekera kwazithunzi zanga zakhala zofiira mu JPEG?
+
Chifukwa JPEG siyimakhala ndi njira ya alfa yoti ikhalemo. Mtundu uliwonse wa pixel umafunika kukhala ndi mtundu wolimba, choncho kuwala kwazithunzi kumapangidwa motsutsana ndi kumbuyo - kuwala koyambirira - nthawi yomwe fayilo idzalemba. Sichingakhalepo chilichonse chobwezeretsedwanso pambuyo pake. Ngati chithunzi chiyenera kukhala patsamba lobiriwira kapena pazithunzi, sinthani ku mtundu womwe umasunga kuwala kwazithunzi. JPEG amagawana zonse JPG kuletsa - palibe alpha, kuwonongeka kwa chitukuko pa re-kupulumutsa - ndi kuwonjezera kukhumudwitsa mapulogalamu amene amaona awiri kuwonjezeka mosiyana.
Kodi JPEG imatha kusamalira CMYK yosindikiza?
+
Ikhoza, amene ndi chifukwa chake fayilo kuchokera kusindikiza workflows nthawi zina kuwoneka zosadziwika pazenera: zobiriwira ndi zoperekedwa mu inki peresenti kwa kusindikiza kuposa kuwala kwa monitor. ambiri web-facing mtundu ndi RGB okha, kotero kusintha ayenera kutanthauzira, ndi kutanthauzira ndi zosawerengeka - saturated cyan ndi orange shift kwambiri. Kwa chilichonse kuyendera kwa wosindikiza, kusamalira oyambirira mbali iliyonse inu kusintha.
Kodi ndi vuto kuti JPEG ili ndi zaka zoposa makumi atatu?
+
Age yekha si vuto - angapo mtundu kuchokera kuti nthawi ndibe bwino, makamaka chifukwa chilichonse chili ndi zaka kuti akwaniritse iwo. Zimene zikukhudza ndi zimene nthawi anaganiza: mavidiyo ang'onoang'ono, mofulumira processors, palibe netiweki, ndi zizindikiro aliyense anafunikabe. Pamene amene anaganizabebe, mtundu ndi bwino. Pamene iwo sachita, kuti ndi chifukwa chosintha.
Kodi ndingagwiritse ntchito JPEG moyenera patsamba la webusaiti?
+
Yes — iliyonse browser pano amasonyeza izo natively, kotero kuti sayenera kupewa uthenga ndi kusintha nthawi yofalitsa. Kuyankhulana kumakhalabe ndi kutalika kuposa kuthandizira: chithunzi chimodzi mu webusaiti yamakono ndi nthawi zambiri theka la kukula pa mtundu wowoneka bwino, zomwe ndi zoyenera kuchita pa chilichonse chomwe chimawonekera pamwamba pa fold. JPEG ndi kuwonjezeka ambiri kamera, scanners ndi Unix-origin mapulogalamu amakonda, ndipo ndi wodziwika padziko lonse.
Kodi ndingasinthe dzina la chidacho popeza JPEG sichisintha?
+
Kwambiri nthawi zonse, ndipo ndi bwino kumvetsa chifukwa chake: kuwonjezeka ndi label, pamene bytes m'maganizo ndi zopangidwa kwa mtundu wina mfundo. Kusintha dzina amapanga fayilo amene dzina lake amalonjeza chinachake za zinthu zake sikuti kubweretsa, ndi zimene amatsegula izo kapena amakana fayilo kapena misreads izo. Mmodzi waukulu kulephera ndi awiri mtundu amene ndi weniweni wofanana wonyamula pansi pa dzina losiyana - ndi ngakhale pamenepo bwino rewrap ndi chitetezo kuposa kusintha dzina.
