Muaj ntau ntau yam ua rau lub suab zoo: qhov kev sib txuas rau broadband, bandwidth, kho vajtse, software thiab technology nws tus kheej. Qhov bandwidth, kho vajtse thiab software yam tseem ceeb nyob rau hauv peb tswj - peb muaj peev xwm hloov thiab tweak thiab txhim kho rau lawv; yog li thaum peb hais txog lub suab zoo hauv VoIP, peb feem ntau taw tes rau cov ntiv tes mus rau lwm qhov, nws yog ib qho uas tshaj li peb cov neeg siv. Ib qho tseem ceeb ntawm VoIP tshuab yog cov ntaub ntawv ceev xwm txheej.
Dab tsi yog cov ntaub ntawv tawm?
Cov ntaub ntawv sau tawm yog cov txheej txheem uas lub suab cov ntaub ntawv tau muab sau cia kom muab nws ua rau nws tsis hloov rau qhov hloov. Compression software (hu ua ib lub codec ) encoding lub suab paj nruag rau hauv cov ntaub ntawv uas nws muab ntim rau hauv sib dua packets uas yog thauj xa hauv Internet. Ntawm lub hom phiaj, cov pob ntawv no tau raug tshem tawm thiab muab lawv cov me nyuam loj (txawm tsis tas), thiab hloov dua siab tshiab rau lub suab analog dua, kom cov neeg siv tau hnov.
Codecs tsis tsuas yog siv rau compression, tab sis kuj rau encoding, uas, tsuas yog hais tias yog tus neeg txhais lus ntawm analog lub suab rau hauv cov ntaub ntawv uas yuav kis tau mus dhau IP tes hauj lwm.
Qhov zoo thiab qhov ua tau zoo ntawm qhov kev txuam software, yog li ntawd, muaj kev cuam tshuam loj rau lub suab zoo ntawm VoIP sib tham. Muaj zoo compression yees thiab muaj cov tsis zoo. Zoo dua hais tias, txhua cov tshuab hluav taws xob yog tsim los rau kev siv rau hauv qee lub sijhawm. Tom qab compression, qee compression yees incur qee tus poob ntawd cov ntaub ntawv cov khoom thiab txawm packets. Qhov no ua rau lub suab tsis zoo.
VOIP thiab Voice Compression
VoIP tswj thiab ua kom cov ntaub ntawv tawm suab hauv ib txoj kev xws li qee qhov ntawm cov suab ntawm lub suab yog ploj lawm. Qhov no yog hu ua kev sib daj sib deev. Qhov poob tsis yog qhov tshuab nyuaj rau lub suab zoo li nws yog qhov tseem ceeb. Piv txwv li, cov suab uas tsis tau hnov los ntawm tib neeg pob ntseg (ntawm ntau zaus dhau los lossis dhau qhov ntawm lub rooj sib hais) yog pov tseg vim tias nws yuav tsis siv. Tsis tas li, silence yog pov tseg. Cov thooj ntawv me me ntawm cov suab nrov yuav poob zoo li, tab sis me me poob hauv lub suab tsis tiv thaiv koj los ntawm kev nkag siab txog cov lus tau hais.
Tam sim no, yog tias koj tus neeg muab kev pabcuam siv cov tshuab txav kom zoo, koj yuav zoo siab; lwm tus koj yuav tsum tau yws yws. Niaj hnub no, compression yees yog li ntawd hais tias lub suab paj nruag yog ze li zoo meej. Tab sis ib qho teeb meem nrog rau kev xaiv ntawm compression software: ntau compression software yoog mus txawv cov kev xav tau. Piv txwv li, muaj qee lub suab, ib txhia rau cov ntaub ntawv thiab qee qhov rau fax. Yog tias koj sim xa cov ntawv fax uas siv lub suab nrawm software, qhov zoo yuav raug kev txom nyem.
Cov ntaub ntawv sib txuam, thaum muaj kev tsim kho thiab siv, yuav yog ib qho yooj yim uas cuam tshuam VoIP saum toj xov tooj hauv xov tooj ntawm cov suab nrov zoo, thiab ua kom zoo zog. Qhov no yuav ua tau kom ntev li ntev tau lwm yam (bandwidth, hardware etc.) zoo. Txij thaum compression lightens lub load ntawm cov ntaub ntawv yuav tsum tau kis tau rau hauv ib lub sijhawm ntawm lub sij hawm, cov qhabnias zoo yuav ua tiav.
Nyeem ntxiv rau cov codecs ntawm no , thiab pom ib daim ntawv teev cov qauv codec uas siv tau tshaj tawm hauv VoIP nov.