Chii AAC-urongwa?

Zvisinei, kuti musi, AAC-youduku harisati kusvika vakawanda kuparadzirwa ruzha vatakuri, vanoverengeka parameters zviri nani kupfuura mamiriro mhando dzose ekuteerera compression, uye saka akakodzera tifunge.

Chii?

Tinotanga ane tsananguro: Audio Manyorerwo AAC ndiyo proprietary (patented) mumwe compression Audio faira. Panguva iyoyo ine kurasikirwa maduku yepamusoro panguva Coding pane MP3 panguva imwecheteyo ikakuruma unodiwa ezvinhu. Uyewo, AAC-youduku chinhu wideband Audio Coding algorithm kuti anoshandisa mbiri huru yeEncoding nhungamiro kuderedza uwandu nemashoko zvaida kuti kupararira yepamusoro-digital Audio. Izvi inotoda kuonekwa mumwe chemhando yepamusoro, akatengeswa pane kurasikirwa compression michina. Pamanyorerwo inotsigira midziyo kupfuura ano, kunyange inotakurika. Zvinofanira kucherechedzwa kuti mhete pasi vari AAC pamanyorerwo zvinogona kutengwa kubva iTunes Store, uye ichi chitoro vari mumhanzi, compressed kungotaurwa achishandisa mutongo. Zvinofanira akati kuti AAC-pamanyorerwo pakutanga akasikwa ari mutsivi MP3, izvo zvinogona kupa nani unhu Coding. Chisarudzo yakabudiswa muna 1997 sezvo idzva, 7th, chikamu mhuri MPEG-2.

musimboti oparesheni

Kana yeEncoding ari pamanyorerwo ichi, zvinotevera pezvakaitwa: imperceptible zvinoumba chiratidzo vanobviswa, vakachenesa pamusoro encoded okuteerera chiratidzo redundancy. Zvadaro, humboo chinogadzirwa maererano nzira maererano MDCT kunzwisisa kwavo. Panguva inotevera Danho Codes anowedzerwa kugadzirisa siyana dzakawanda zvikanganiso. Pakupedzisira, chiratidzo iri inoparadzirwa kana kuponeswa.

All mashoko

Sezvineiwo, AAC-pamanyorerwo ane zvakabudiswa kakawanda pakati 8-96 kHz uye uwandu mugero vari penguva 1-48. MP3 Mbeu dzakauchikwa anoshandisa chine filters. Rinoreva dzakachinjwa discrete cosine rokuchinja, zvinozoita AAC pa yakawedzerwa mwero "mahwindo", iro rinosvika 2048 points.

Saka, AAC zvikuru wakanyatsokodzera encode mashoko ekuteerera rukova ane zvakaoma kupomba uye mativi-wave anonongedzera, achienzaniswa MP3. Format akawana kukwanisa dynamically chinja ari MDCT chinogumbura urefu kuwanda 2048-256 pfungwa iri. Kana paine pfupi kana imwe iya, akashandisa "hwindo" duku 256 pfungwa kuti vawane chisarudzo nani. Panyaya iyi, iyo default ndiyo 2048-pfungwa huru "hwindo" kuti maximize yacho Coding kunyatsoshanda. AAC ane nhamba zvakanakira ichienzaniswa senguva MP3. Pakati pavo tinofanira kutaura: Kuzadziswa vakawanda ekuteerera migero (kusvika 48), chinokosha Coding kushanda pasi ezvinhu tinyanye uye shanduka ikakuruma mwero uye zvakabudiswa kakawanda muna zvinobva 8 Hz kusvika 96 kHz (nokuti MP3, nhamba iri kubva 8 Hz kusvika 48 kHz) uye zvimwe kusanduka chinokosha nzira inonzi Joint redhiyo. Sezvo zvinogadzirisa, "AAC +" - mumwe codec rinonyatsotarira uchishanda yakaderera ikakuruma unodiwa. Kunosanganisira SBR uye AAC LC, nokudaro kuwana inzwi rakanaka atova kuwanda 32-48 kbit / s.