Yintoni AAC-format?

Ukuza kuthi ga ngoku, AAC-format nangoku sele bengekafiki ezisasazwayo abathwali isandi, Noko ke, kukho inani parameters ungcono zonke iintlobo langoku ucinezelo emanyelwayo, ngoko ufanelwe ingqalelo yethu.

Yintoni na?

Siqala inkcazelo: somsindo AAC yi wezindlu (elilodwa lomenzi) ucinezelo omnye audio ifayile. Ngelo xesha nye na ilahleko encinci umgangatho ngexesha ikhowudi ngaphezu MP3 kwi kweemeko isantya sebhithi elifanayo. Kwakhona, AAC-Ifomati luluhlu ikhowudi wideband algorithm usebenzisa ezimbini encoding engundoqo umgaqo ukunciphisa kakhulu inani wedatha efunekayo ukugqithisa of ezikumgangatho ophezulu audio yedijithali. Esi sisombululo kucingelwa ukuba yenye yezona umgangatho ophezulu, ithengiswe xa kukho ilahleko zobugcisa ucinezelo. Ifomati ixhasa izixhobo kakhulu mihla, nokuba ephathekayo. Kufuneka kuqatshelwe ukuba iithowuni ikhonkco format AAC zingathengwa evela iTunes Store, kwaye kule venkile kukho umculo, zixinaniswe kuphela esebenzisa sigqibo. Kufuneka kwakhona wathi AAC-ifomati ekuqaleni wadalwa ozothatha MP3, leyo ukunika oluphuculweyo iikhowudi esemgangathweni. Esi sigqibo yapapashwa ngo-1997 njengoko entsha, 7, yinxalenye yentsapho ka-MPEG-2.

isimiso ukusebenza

Xa usebenzisa ikhowudi kule fomati, ezi nkqubo zilandelayo: amacandelo imperceptible yomqondiso zisuswe, icocwe le encoded komsebenzi umqondiso odiyo. Emva koko, i data kusingathwa ngokungqinelana indlela ngokuhambelana MDCT xaka wabo. Kwinqanaba elilandelayo le khowudi ezidityaniswe ukulungisa iimpazamo ezahlukeneyo lwangaphakathi. Ekugqibeleni, uphawu usasazwa ugqithiselwa okanye basindiswe.

zonke iinkcukacha

Okubangel 'umdla kukuba, loo AAC-ifomati umntu rhoqo ezinye phakathi 8-96 kHz kunye nenani imijelo lokuphumla 1-48. MP3 Hybrid isebenzisa iseti okucoca ulwelo. Libhekisela cosine obubobu ilungiswe inguqu, bona AAC kwi ukunyuka izinga "windows", nto leyo efikelela amanqaku 2048.

Ngenxa yoko, AAC kakhulu ngakumbi ezilungele uku encoder i komsindo kokuba ukubetha kwentliziyo square-wave complex iimpawu, xa kuthelekiswa ne-MP3. Format wazuza ubuchule ukuswitsha ngonyanzelo kwi ubude MDCT block kuluhlu 2048-256 amanqaku. Ukuba kukho i-ixesha elifutshane okanye shift enye, wasebenzisa "window 'amancinane amanqaku 256 ukuze kuphunyezwe isisombululo ngcono. Kulo mzekelo, okungagqibekanga ngongoma-2048 ezinkulu "window 'ukuba ukwandisa ukwanela ikhowudi. AAC inenani yeenzuzo xa kuthelekiswa ne-MP3 njengesiqhelo. Phakathi kwabo kufuneka ukhankanye: nokuzalisekisa inani elikhulu lamajelo odiyo (ukuya kwi-48), ebalulekileyo ikhowudi ukusebenza phantsi kweemeko isantya sebhithi rhoqo kunye neguquguqukayo kunye novavanyo rhoqo kuluhlu ukususela 8 Hz ukuya 96 kHz (ngenxa MP3, eli nani ukusuka 8 Hz ukuya 48 kHz) kunye indlela ekhethekileyo dyondzisaka ekuthiwa stereo Joint. Ke ukuba izisombululo, "AAC +" - codec elinikele ekusebenzeni kunye isantya sebhithi eliphantsi. Ngaba indibanisela SBR kunye AAC LC, ngaloo ndlela ekufezekiseni isandi elungileyo sele ku ezahlukene 32-48 kbit / s.