MP4 → WebP

Yambitsani mu wosewera, peza nthawi ndi kukumbukira nthawi, chifukwa MP4 sichimangokhala ndi zilembo za kapitoli kuti mupite. Pezani kuti mu gawo la nthawi yoyamba, wonjezera nthawi yotha, ndipo wosintha amafuna kumapeto kwa nthawiyo ndipo amachotsa malire omwe mwafunsidwa. Kufuna ndi koyenera kwa frame, koma kumatha kukhala koyenera ngati idadi yomwe imaperekedwa - onetsetsani kuti ndi yoyenera panthawi yoyamba ya kanemayo. MP4 amathandiza okha imodzi yotchuka subtitle mtundu (mov_text), ndi multi-traka audio ndi osati olimba m'malo desiki osewera.

A MP4 ndi fayilo ya ISO base-media, ndipo izi zitha kusinthidwa ngati chiwonetsero chazithunzi mu chotengera, osati posintha ma pixels - chifukwa chake clip yomwe ikugwiritsidwa ntchito mozungulira pafoni ikhoza kuwonekera m'modzi mwa osewera ndikukhala pambali pamodzi. Animation imapangidwa kuchokera ku pixels yosinthidwa, kuti chiwonetserocho chiyenera kuvomerezedwa pambuyo polemba chiwonetsero choyamba; ngati chithunzicho chimabwerera m'mbali, sinthani malo ochokera ndikusinthanso. Zonse zina za kamera kapena wolemba wolemba ndi nkhani yovuta: kanema wa kanema, mzere wokhazikika wa ma frame. Zikuoneka kuti pafupifupi aliyense MP4 m'munda ndi H.264 kanema ndi AAC audio; chidebenso mwalamulo ali HEVC, AV1 ndi VP9.

Yai, pamene muli ndi fayiloyo. A MP4 ndi zomwe webusaitiyi imagwiritsa ntchito kwa kanema wophatikizidwa chifukwa mabrowser amasewera popanda plugin, kotero clip yomwe imasewera mu tabu nthawi zambiri ndi MP4 yokhayo yomwe imasunga ndi kutsitsa pano monga fayilo ina iliyonse. Kulephera ndi wosewera wosewera yemwe amapatsa ma segments ofupi omwe amawerengedwa m'malo mwa fayilo imodzi - omwe ayenera kusinthidwanso pambuyo poti chilichonse chitha kusinthidwa. Malamulo ndi chinthu china chomwe chimayenera kutsimikiziridwa: kutsitsa kanema sichifanana ndi kuloledwa kufalitsanso animation yomwe idapangidwa kuchokera ku izo. MP4 ndi otetezeka zotheka kutumiza zolinga - aliyense foni, browser, console, wolemba ndi Smart TV anamanga mu zaka zapitazi amasewera izo popanda mapulogalamu atsopano.

Lossy, kwa chilichonse chomwe chimayamba ngati kanema. Animated WebP ingakongoletse ma frame ake mosiyana: mode ya lossless imasunga ma pixel onse ndi kugwirizana ndi zithunzi zopanda malire ndi mawu a pazenera, pomwe mode ya lossy imagwiritsa ntchito kuyembekezera kwa block-based monga momwe video codec imagwiritsa ntchito ndi kugwirizana ndi zithunzi zachilendo. Frames za kamera ndi zokhala ndi ma granules ndi ma gradients omwe lossless compression sapeza mzere, choncho animation ya lossless ya kanemayo imatha kuyendetsa nthawi zambiri kuposa ya lossy yomwe ikuwoneka ngati yofanana. Ikani ya lossy ngati cholinga chake sicho kujambula kwa skrini ndi mawu owoneka bwino. WebP ndibe yachiwiri-katundu kunja kwa browser — kusindikiza workflows, zaka zakale Office zomanga ndi ena foni galleries sakuvomereza izo.

Animated WebP imagwira ntchito bwino kwambiri pa mavidiyo opitilira masekondi 10. Pambuyo pake, fayilo imawoneka ngati mabala (GIF ndi yosasinthika). Panthawi ya animations yaitali, imagwiritsa ntchito WebP kapena APNG, zomwe zonse zimagwiritsidwa ntchito pogwiritsa ntchito kusindikiza kwa video-codec-grade ndi kukulitsa bwino.

GIF yokhala ndi ma animations: 2 mpaka 8 MB pa 480p malinga ndi kuvuta kwa kugwira ntchito. WebP yokhala ndi ma animations: 200 KB mpaka 1 MB pa kusiyana kwa kutalika ndi kukula kwa zithunzi. WebP amapatsa modes lossy ndi lossless, ndi alpha kuwala ndi animation alipo m'modzi kapena m'modzi.

Mwa default timalowetsa mpaka 15 fps kwa GIF yoanima (yokhala ndi mavuto owoneka bwino kuposa 25 fps) ndi 24 fps kwa WebP / APNG yoanima (yoyang'anira mitengo yotsika bwino).

Sichoncho — mtundu wa WebP wokhala ndi ma animations (GIF, WebP, APNG) susunga mawu. Ngati mukufuna mawu, yesani mtundu wa kanema (MP4, WebM) m'malo mwa mtundu wa chithunzi chokhala ndi ma animations.

Ndiyo — njira yowerengera loop-count imawongolera ngati WebP imayenda mopanda malire (zosasinthika), imasewera nthawi N, kapena imasewera nthawi imodzi. Kuwerengera kwa loop kusungira mu metadata ya WebP yokhala ndi bokosi ndipo imavomerezedwa ndi aliyense woonera watsopano.

Zifukwa ziwiri zofala. Choyamba, kuchepetsa kuchuluka kwa mafremu: 15 fps WebP kuchokera ku 60 fps MP4 kumachepetsa 75% ya mafremu; kuchotsa ndi slider ya kuchuluka kwa mafremu. Chachiwiri, kuwonjezera kwa palette: GIF imatha kujambula mpaka 256 ya mitundu ndipo gradient-heavy MP4 imawoneka bwino. Sungani ku WebP yoanima kuti mudziwe momwe zinthu ziliri ndi mitundu yonse.

Ndiyo — njira yosintha kukula imachepetsa MP4 kumbuyo pa kutulutsa ma frame, zomwe zimachepetsa kwambiri kukula kwa fayilo ya WebP. 480p WebP kuchokera ku 4K MP4 ndi pafupifupi 16x yaying'ono kuposa 4K WebP. Pezani /video-cutter/ kuti muchepetse m'njira yosiyana.