Kodi PCM audio ndi chiyani ndipo ndifunika bwanji
PCM imayimira P ulusi C ode M kudandaula.
PCM imagwiritsiridwa ntchito kusandutsa zizindikiro zamanema za analogi (zoimiridwa ndi mawonekedwe a mawonekedwe) zomwe zimayimilidwa ndi 1 ndi 0-mofanana ndi deta ya kompyuta) popanda kuponderezedwa . Izi zimalola kujambula kwa nyimbo kapena filimu ya mafilimu kuti igwirizane ndi malo ochepa (kuyerekeza kukula kwa CD ku vinyl rekodi).
Maziko a PCM
Kutembenuka kwa audio kamodzinso kwa PCM kungakhale kovuta, malingana ndi zomwe zili kutembenuzidwa, khalidwe lofunikira kapena lofunidwa, ndi momwe chidziwitsocho chimasungidwira, kusamutsidwa, kapena kupatsidwe. Komabe, izi ndizofunikira.
Fayilo ya PCM ndikutanthauzira kwadijito kwawimbiro la analoji. Cholinga ndikutanthauzira zofunikira za chizindikiro cha audio analog kwambiri.
Njira yomwe kutembenuzidwa kwa analog-to-PCM yachitika kudzera mwa ndondomeko yotchedwa sampling. Monga tafotokozera pamwambapa, mawu a analog amayenda mafunde, pamene PCM ndi mndandanda wa 1 ndi 0. Kuti mutenge mawonekedwe a analog pogwiritsira ntchito PCM, mfundo zenizeni pawotchiyo ziyenera kusankhidwa (mafupipafupi). Zomwe zimapangidwira pazomwe zimaperekedwa (bits) ndi mbali imodzi ya ndondomekoyi. Zolemba zambiri zowonjezereka ndi zidutswa zazikulu za mawotchi omveka panthawi iliyonse zimatanthawuza molondola kwambiri pamapeto omvetsera. Mwachitsanzo, mu audio CD, mawonekedwe a analogi sampulikidwe 44.1 zikwi pa mphindi (kapena 44.1kHz), ndi mfundo zomwe 16bits kukula (kuya). Mwa kuyankhula kwina, makanema ojambula pa audio ya CD ndi 44.1kHz / 16bbits.
Nyumba ya Mafilimu Akumasewera ndi Akumudzi
Mtundu umodzi wa PCM, mndandanda wamakina owonjezera (LPCM), umagwiritsidwa ntchito pa CD, DVD, Blu-ray Disc, ndi mauthenga ena omvera a digito.
Mu CD, DVD, kapena Blu-ray Disc player, LPCM (yomwe imatchulidwa ngati chizindikiro cha PCM) imawerengedwa pa diski ndipo ikhoza kusamutsidwa m'njira ziwiri:
- Njira imodzi ndiyo kusunga mawonekedwe ake a digito ndi kutumiza chizindikiro chimenecho kumalo opitiramo zisudzo pogwiritsa ntchito digito, digital coaxial , kapena HDMI . Wolandirayo ndiye akutembenuza chizindikiro cha PCM kwa analog kuti icho chikhoze kutumizidwa kupyolera pamakina amphamvu komanso kwa okamba. Chifukwa chomwe chizindikiro cha PCM chiyenera kutembenuzidwira ku analog ndikuti khutu laumunthu limagwira ntchito pomva zizindikiro zamanema za analog.
- Njira yachiwiri ndi ya CD, DVD, kapena Blu-ray Disc player kuti isinthe mawonekedwe a PCM kubwereza fano la analowe mkati, ndiyeno kusamutsa chizindikiro cha analog chokonzedwanso kachiwiri kumalo osungirako nyumba kapena wolandira stereo kudzera kulankhulana za ma analog. Pachifukwa ichi, wolandila stereo kapena makina oyendetsa kunyumba samasowa kutembenuka kwina kulikonse kuti mumve phokoso.Asewera a CD ambiri amapereka mauthenga a analog audio, choncho amafunika kuti chizindikiro cha PCM pa disc chimasinthidwe kwa analog ndi wosewera mkati. Komabe, ena osewera CD (komanso pafupifupi onse DVD ndi Blu-ray Disc) akhoza kutumiza chizindikiro cha audio PCM mwachindunji pogwiritsa ntchito mawonekedwe a digito kapena digital coaxial connection. Kuwonjezera pamenepo, ambiri a DVD ndi Blu-ray Disc angaperekenso chizindikiro cha PCM kudzera ku kugwirizana kwa HDMI.
PCM, Dolby, ndi DTS
Chinthu chinanso chimene ambiri a DVD ndi Blu-ray Disc angakhoze kuchita ndicho kuwerenga zizindikiro za audio za Dolby Digital kapena DTS . Dolby ndi DTS ndizojambula zojambulajambula zamagetsi zomwe zimagwiritsira ntchito ma coding zomwe zimaphatikizapo chidziwitsocho kuti zigwirizane ndi chidziwitso chonse cha mauthenga omvera pakompyuta pa DVD kapena Blu-ray Disc. Kawirikawiri, mafayilo opangidwa ndi Dolby Digital ndi DTS osamvetsetsedwere amasamutsidwa kumalo osungirako zisudzo zapanyumba kuti apitirize kufotokoza kwa analog-koma pali njira ina.
Mukangopatula diskiti, ma DVD ambiri kapena Blu-ray Disc angasinthe mkati mwawo kusintha Dolby Digital ndi DTS mawonekedwe kuti PCM osasinthika, ndiyeno kudutsa chizindikiro chojambulawo molunjika kunyumba yamasewu wolandila kudzera HDMI kugwirizana, kapena kusintha chizindikiro PCM kuti analog kwa zotuluka kudzera ma audio analog awiri kapena ochuluka omwe amachokera kumalo otsekemera a nyumba omwe ali ndi zotsatira zofanana.
Komabe, popeza chizindikiro cha PCM sichiri chosasinthika, chimatenga malo ambiri opatsirana. Choncho, ngati mukugwiritsira ntchito mawonekedwe a digito kapena coaxial, pali malo okwanira kuti mutumizire njira ziwiri za PCM audio. Kusewera kwa CD komwe kuli bwino kwambiri, koma kwa zizindikiro zozungulira Dolby Digital kapena DTS zomwe zasandulika ku PCM, muyenera kugwiritsa ntchito kugwirizana kwa HDMI, chifukwa ikhoza kusinthanso mpaka 8 ma PCM audio.
Kuti mudziwe zambiri zokhudza momwe PCM imagwirira ntchito pakati pa sewero la Blu-ray ndi wolandila nyumba, onetsani ma CD Audio Player: Bitstream vs PCM .