Kodi AAC-mtundu?

Pakali pano, AAC-mtundu akadali sizinawakhudze kupezeka kwa phokoso onyamula Komabe, chiwerengero cha magawo ndi wapamwamba kwambiri kuposa mitundu yonse panopa psinjika wailesi, choncho kuchilingalira wathu.

Ndi chiyani icho?

Timayamba ndi tanthauzo la: zomvetsera mtundu AAC ndi kampani (setifiketi) limodzi psinjika zomvetsera file. Pa nthawi yomweyo ali ndi imfa ang'onoang'ono a khalidwe pa wolemba pulogalamu kuposa MP3 pa yomweyo zinthu mlingo pang'ono. Komanso, AAC-mtundu ndi wideband zomvetsera 'kala' ikusonyeza aligorivimu kuti amagwiritsa ziwiri zazikulu kabisidwe mfundo kuchepetsa chiwerengero cha deta wofunikila kufala kwa apamwamba zomvetsera yadigito. njira Izi imodzi wapamwamba kwambiri, anagulitsa pa kufa luso psinjika. mtundu mfundo yoti zida zamakono kwambiri, ngakhale kunyamula. Tikumbukenso kuti mphete malankhulidwe mu AAC mtundu zikhoza kugulidwa ku sitolo iTunes, ndi mu sitolo ili ndi nyimbo, wothinikizidwa potsatira njira zochita. Tiyeneranso ananena kuti AAC-mtundu pachiyambi analengedwa monga wolowa MP3, Lomwe lingathe kupereka abwino 'kala' ikusonyeza. Chigamulo linatulutsidwa mu 1997 monga latsopano, 7, mbali ya banja la MPEG-2.

Mfundo ntchito

Pamene kabisidwe mu mtundu uwu, njira zotsatirazi: zigawo imperceptible cha chizindikiro amachotsedwa, kuyeretsa wa ozimbayitsidwa zomvetsera redundancy chizindikiro. Kenako, deta kukonzedwa malinga ndi njira mogwirizana ndi MDCT Kuvuta awo. Pa siteji yotsatira zizindikiro ndi anawonjezera kuti akonze zolakwika zosiyanasiyana mkati. Pomaliza, mbendera imafalikira kapena kupulumutsidwa.

tsatanetsatane

N'zochititsa chidwi kuti AAC-mtundu ali ndi zochepa chabe pamalangizo pafupipafupi pakati 8-96 kHz ndi chiwerengero cha njira mu imeneyi 1-48. MP3 Zophatikiza amagwiritsa ya Zosefera. Zimatanthauza kusinthidwa apawokha cosine asinthe, nayenso AAC pa mlingo kuchuluka kwa "mazenera" imene imafikira mfundo 2048.

Choncho, AAC kwambiri wosakanikirana ndi encode mtsinje zomvetsera ndi zovuta kugunda kwa mtima ndi lalikulu-yoweyula chizindikiro, poyerekeza ndi MP3. Mtundu wabweza luso pompopompo kusinthana mu utali MDCT njerwa mu uthunthu mfundo 2048-256. Ngati pali yochepa kapena kosangalatsa umodzi, ntchito yaing'ono "zenera" mfundo 256 polinga kuti apindule bwino kusamvana. Mu nkhani iyi, kusakhulupirika ndi 2048-mfundo zazikulu "zenera" kudzapeza ya 'kala' ikusonyeza dzuwa. AAC angapo ubwino poyerekeza ndi alipidwa MP3. Pakati pawo Tiyenera kutchura: kukwaniritsidwa kwa ambiri njira zomvetsera (mpaka 48), kwambiri wolemba pulogalamu Mwachangu pansi zikhalidwe za mlingo zonse ndi variable pang'ono ndi zochepa chabe pamalangizo pafupipafupi mu osiyanasiyana kuchokera 8 Hz kuti 96 kHz (kwa MP3, chithunzi ichi ndi chochoka 8 Hz kuti 48 kHz) ndi zambiri kusintha mode wakupambulika dzinache olowa sitiriyo. Monga njira zothetsera, "AAC +" - ndi codec lolunjika pa ntchito ndi mlingo wochepa pang'ono. Ndi osakaniza SBR ndi AAC LC, potero kukwaniritsa zikumveka bwino kale mu osiyanasiyana 32-48 kbit / s.