Sinthani M4A ku AMR

Ndikukhulupirira kuti ndinu oyenera, ndipo ndibwino kuti mupange. Mafomu awiriwa ndi owonongeka, choncho AMR encoder akuchita ntchito kuchokera ku audio yomwe yakhala ikuyenda mwa psychoacoustic pass, ndipo masankho ake oyamba amapanga gawo loyamba. Pa 192 kbps kapena pamwambapa, zotsatirazi ndizosawoneka bwino kwa ambiri owerenga. Ngati muli ndi master yopanda kusowa, kulemba koyamba kwa AMR kuchokera ku yomwe imalepheretsa kupita kwachiwiri kwathunthu. M4A ali AAC m'malamulo ambiri, kapena Apple Lossless (ALAC) pamene anachokera ku lossless rip. AMR ndi narrowband mawu codec kuyendetsa pakati pa 4.75 ndi 12.2 kbps, modeling munthu woimba m'mimba kuposa wonse audio spectrum.

Siyimagwira ntchito. M4A imathamanga ndi metadata block yoyenera, koma AMR siyimagwira ntchito yoyenera ya woimba, album, track number kapena cover art, kotero ma tag amatulutsidwa osati kuwonongedwa. Tengani M4A ngati kopita kokhala ndi tag, kapena gwiritsani ntchito njira zina monga Mp3tag kapena MusicBrainz Picard. AMR amawononga nyimbo: yake 8 kHz bandwidth amachotsa zonse pamwamba foni ma frequencies, ndi palibe ndalama ya re-encoding amabweretsa izo kumbuyo.

Idzaikidwa pansi pa stereo, chifukwa AMR siyimakhala ndi njira yogwiritsira ntchito ma channel ambiri. Kulowetsa kumagwiritsa ntchito ma coefficients ovomerezeka kuti ma channel apakati azikhala owoneka bwino ndipo ma surrounds amaphatikizidwa pamalingaliro otsika. Chomwecho chilichonse chomwe chimadalirika pa malo osiyana a ma channel chimapita pamene ichi chikuchitika.

DRM. Mtundu wa M4A mafayilo amasinthidwa ndi sitolo kapena pulogalamu yomwe idatulutsa, ndipo mawu osakira satha kusinthidwa ndi aliyense wosintha. Chomwecho chomwe mwachotsa nokha, cholemba, kapena chogula popanda kuteteza chimasinthidwa moyenera; kugula kwa licensed sichidzachitika. M4A amachititsa zinthu ziwiri kwambiri zosiyana m'mbuyo kwa m'modzi kuwonjezeka - lossy AAC ndi lossless ALAC - ndi non-Apple hardware thandizo ndi zosagwirizana.

Chifukwa chimodzi mwazigawo zake ndi codec ya mawu kuposa codec ya nyimbo. Imakhala ndi maonekedwe a munthu woimba ndipo imachotsa chilichonse m’mbali mwa bandwidth ya foni, chomwe ndi choyenera kwa mawu olemba mawu komanso chowononga kwa chilichonse chomwe chili ndi zida. Kusintha kuchokera ku izo sikungabwezeretse ma frequencies osakhudzidwa — iwo sanali kusinthidwa pamalo oyamba.

Default ndi 192 kbps kwa lossy AMR; pass-through kwa lossless AMR. Kusintha kwa 320 kbps kwa audiophile kapena 64-96 kbps kwa mawu olankhula audiobooks (owoneka bwino kwa mawu, amadula kukula kwa fayilo).

Ngati M4A ndi lossy ndipo AMR ndi lossless (mwachitsanzo MP3 → WAV), fayilo ya AMR si yabwino kuposa M4A - simungathe kubwezeretsa zambiri zomwe zatulutsidwa. Ngati M4A ndi lossless ndipo AMR ndi lossy, yembekezerani kuti codec ya AMR ibwezeretse; pa 192 kbps izi ndi zosawoneka bwino kwa zinthu zambiri.

Ndikoyenera - dzina, woimba, album, chaka, mndandanda wa nyimbo, album art, ndi masamba olemba (ofunika kwambiri kwa audiobooks) amawerengedwa kuchokera ku M4A ndipo amalemba mu AMR wokhala ndi AMR mtundu umathandizira ma tag. M4B audiobook structure round-trips into M4B and AAX → M4B output.

Yai - chotsani fayilo ya M4A ndikuwapanga mofanana. Premium ili ndi ogwira ntchito ambiri mofanana ndi malire a fayilo, kotero fayilo ya 500-file batch imatha m'maola angapo osati m'maola angapo.

Mwachidule ndi yemweyo (48 kHz M4A → 48 kHz AMR). Ngati mukufuna kuchepetsa kusamvana kwa kugwirizana (mwachitsanzo 96 kHz → 44.1 kHz kwa kulemba CD) kusankha kwa kusamvana kwamphamvu kumachita izi ndi kusamvana kwabwino.

Ndiye — njira yosintha mawu imagwiritsa ntchito ITU-R BS.1770 / EBU R128 yosintha mawu ku AMR, yolenga -14 LUFS (mtengo wosinthira), -16 LUFS (mtengo wosinthira podcast), kapena -23 LUFS (mtengo wosinthira audiobook).