M4V → JPG

Ayinjalo ukuba ziyindawo ebonakalayo yokulandela umbhalo osezantsi ephepheni. I M4V igcina umbhalo osezantsi ephepheni njengendlela yabo yokuhamba kwaye umdlali uzoba ngaphezulu komfanekiso ngexesha lokudlala, ngoko ke isakhelo esikhowudiweyo umguquli ubhala ngaphandle njenge JPG inee-pixels ezicocekileyo ezantsi. Iisihloko ezisezantsi eziboshwe kwividiyo phambi kokuba ibe yi M4V ziyingxaki eyahlukileyo - ngoko ziyinxalenye yomfanekiso kwaye yonke i-frame ekhutshwe igcina ezi.

Ayiba iqhosha elinye, kodwa i M4V iyenza ibonakale icacile: iimpawu zesiqendu zigcinwa kwisiqulathi seefayili njengeziphawuli zexesha ezibizwa ngokuba ziphawuli zexesha, ngoko funda uluhlu lwesiqendu ngaphandle kwefayile kwaye ucofe ezixesha kwindawo yesiqendu sexesha. Ufumana enye JPG kwisiqendu ngasinye, ngokulandelana, eyiyo indlela eqhelekileyo yokwakha imifanekiso eqingqiweyo yoshicilelo olude. Amacebo angenamanqaku esiqendu ashiya ukukhetha imiboniso ngemehlo endaweni. I-M4V igcina abaphawuli besiqendu, umsebenzi wobugcisa kunye nengoma yesihloko esingaphantsi kwisimo i-Apple TV app ilindeleyo, eyona MP4 iqhelekileyo ihlala ilahlekelwa yiyo.

Ubunjani 85 bumiselwe ngokungagqibekanga kwaye lusetyenziswa ngaphandle kokuba utshintshe - olubonakalayo olungaqhelekanga kumvelaphi kumgama oqhelekileyo wokubona, malunga neshumi lesihlanu lobungakanani obulinganayo olungenamonakalo. Nqakraza kwi 95 nantoni na ezakuhlela okanye ishicilelwe, kwaye khupha kwi 70 yemifanekiso eqingqiweyo apho ubungakanani bulawula. I-JPG ilahlekile: umfanekiso uguqulwa nge-DCT, i-quantized, kunye ne-entropiya-ekhowudiweyo, ngeqhosha lomgangatho elilawula ukuba kuphi okuninzi okulahlekileyo.

Ubungakanani obufanayo ne-M4V ividiyo — i-1080p M4V ivelisa i-1920×1080 JPG ii-frames; i-4K M4V ivelisa i-3840×2160 JPG ii-frames. Sebenzisa uncedo lokuguqula ubungakanani emva kokukhupha ukuba ufuna ii-thumbnails ezincinci okanye ubungakanani be-social-media-crops.

Ewe, kodwa uqaphele ngobalo lweefayili - i-30fps 1-minute M4V ivelisa i-1,800 JPG iifayili. Sizipakisha kwi-ZIP ngokuzenzekelayo. Kwiiclip ezide, ukhetho "1 ngomzuzwana" (iifayili ezi-60) okanye iziqinisekiso zexesha elikhankanyiweyo zinika isiphumo esiphathwayo.

Ewe — umbala uguqulwa kwikhowudi nge-matrix esetyenziswa ngumboneleli M4V (BT.709 ye-HD, BT.2020 ye-4K HDR). Umboneleli we-HDR udweliswe nge-tone-mapping kwi-SDR xa uphuma kwi-JPG kuba i-JPG ifomati (PNG, JPG) ayikwazi ukugcina i-HDR pixel ranges ngokusemthethweni.

Ixhomekeke kwisisombululo kunye ne-JPG codec. I-1080p PNG frame ihlala i-2 ukuya kwi-5 MB; i-1080p JPG kwi-quality-85 i-200 ukuya kwi-500 KB; i-4K PNG i-6 ukuya kwi-15 MB. Kwimeko egqithisileyo, ukukhupha i-PNG frame nganye ye-10-minute 1080p M4V kwenza ~50 GB ngokupheleleyo.

Isiqulathi seefayili M4V asigcinanga i-EXIF yesakhelo ngasinye ngendlela ikhamera ehlala isebenza ngayo, ngoko ke ii-JPG iifayili ziphuma nge-EXIF engenanto. Sifaka `creation_time` indawo ebonisa umhla wokugqitywa kwesakhelo somthombo ukuze uphinde ulungelelanise i-bundle ngokulandelana kokuthatha.

Ukukhupha isakhelo kukhawuleza - ngokuqhelekileyo 20 ukuya kwi 30% yobude bomthombo kwindlela eqhelekileyo yokuhambisa. Imini emihlanu M4V → JPG iqela ligqiba malunga nemizuzu ngaphandle kokucinga ngobalo lwesakhelo, kuba ibhotile yengxowa yi JPG encoder, hayi i M4V demuxer.

Ewe - ukhetho oluphambili luyakwamkela uluhlu oluhlukaniswe nge-comma lweziqinisekiso zexesha (umzekelo `00:01:23,00:05:00,00:10:42`) kwaye luvelisa ifayile enye JPG ngesatifiketi sexesha ngasinye. Isetyenziswa kwizifundo ezincinci zesahluko, iziganeko ezibhekisa kwimifanekiso, okanye izifundo ezide ezibonisa imifanekiso emifutshane.

Ewe - imodeli yobumfihlo efanayo neyokuguqulwa ngalinye. Ividiyo yombhalo kunye nee-JPG ze-frames ezikhuphiweyo ziqhubekekiswa kubasebenzi abakhuselekileyo kwaye zicinywe kwimizuzu; akukho hlaziyo lomuntu, akukho qeqesho lwe-corpus, akukho kufikelela kweqela lesithathu.