Ndikukhulupirira kuti ndinu okondwa ndi izi, ndipo ndi chinthu chimodzi chofunikira kudziwa za mtunduwu. Kawirikawiri, kupulumutsa kumayendetsanso kuwonongeka kwa encoder pazithunzi zomwe zakhala zikuyenda, ndipo izi zimayambitsa zinthu zosadziwika - zomwe zimawoneka ngati zoletsa m'mawu ndi haloes pazovuta zazikulu pambuyo pa zaka zambiri. Sinthani kuchokera ku master yopanda kusowa ndi kutumiza ku JPG kamodzi, pamapeto pake, kuposa kutsegulanso ndikubwezeretsanso fayilo yomweyo. JPG ndi lossy: chithunzi chimasinthidwa ndi DCT, quantised, ndi entropy-coded, ndi quality knob kuwongolera momwe ambiri amawonongedwa.
N'chifukwa chiyani kamkodi ndi kachitidwe ka kachitidwe ka kachitidwe ka JPG?
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Chifukwa mtundu ndi wosavuta kulemba pa real-nthawi pa hardware modest, ndipo chifukwa chiyambi cha kujambula zida anapanga m'madera ake ndi nthawi zonse kusinthidwa. The chipangizo sichichita chisankho chabwino, ndi kulemba zimene zake firmware akudziwa. Izi ndi chifukwa chakenso mavidiyo ndi zochepa kwa zimene ali ndi chifukwa chake kusintha iwo ndi nthawi zambiri chinthu choyamba aliyense amachita. JPG ndi JPEG standard kuchokera 1992, ndipo pambuyo zaka zitatu ndibe format ambiri kamera ndi ambiri mawebusaiti kugwiritsa ntchito kwa zithunzi.
Chifukwa JPG siyimakhala ndi njira ya alpha yoti ikhalemo. M'malo mwake, ma pixel onse ayenera kukhala ndi mtundu wolimba, choncho kuwala kwamkati kumapangidwa ndi kuwala kwamkati - kuwala koyambirira - nthawi yomwe fayilo idzalemba. Sichingakhalepo chilichonse chobwezeretsedwanso pambuyo pake. Ngati chithunzichi chiyenera kukhala patsamba lowala kapena pazithunzi, sinthani ku mtundu womwe umasunga kuwala kwamkati. JPG alibe kuwala, degraded m'tsogolo nthawi iliyonse kuti ndi re-kupulumutsa, ndi kutulutsa zooneka kuletsa pa flat mtundu ndi zosaoneka malemba.
Kodi JPG imatha kusamalira CMYK yosindikiza?
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Ikhoza, amene ndi chifukwa chake fayilo kuchokera kusindikiza workflows nthawi zina kuwoneka zosadziwika pazenera: zobiriwira ndi zowunikira za ink peresenti kwa kusindikiza kuposa kuwala kwa monitor. ambiri web-facing mtundu ndi RGB okha, kotero kusintha ayenera kutanthauzira, ndi kutanthauzira ndi zosakira - saturated cyan ndi orange shift kwambiri. Kwa chilichonse kuyendera kwa wosindikiza, kusamalira oyambirira mbali iliyonse inu kusintha.
Kodi ndi chinthu chofunika kuti JPG ali ndi zaka zoposa makumi atatu?
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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 zimene anaganizabebe, mtundu ndi bwino. Pamene iwo sachita, kuti ndi chifukwa chosintha.
Kodi kamera ndi malo a metadata amasungidwa pamene ndimasintha JPG?
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Zimachitika pamene mtundu woyenera umathandizira - kamera ya kamera, kuwala, nthawi yotenga, ndi GPS coordinates ngati chipangizocho chidalemba. Kuti chachiwiri chimayenera kuganiziridwa pambuyo pa kufalitsa: chithunzi chochokera pafoni chimatha kubweretsa malo oyenera omwe adatengedwa. Kuchotsa metadata nthawi yosintha pamene chithunzi chikuyenda komweko kwa anthu.
Kodi ndingagwiritse ntchito JPG moyenera patsamba la webusaiti?
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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 3/4 ya kukula pa mtundu wowoneka bwino, zomwe ndi zoyenera kuchita pa chilichonse chomwe chimawonekera pamwamba pa fold. JPG imatulutsa zithunzi zobiriwira bwinobwino ndipo imatha kuwerengedwa ndi chilichonse chogwiritsa ntchito, msakatuli ndi wosindikiza.
