gryllos_001 Δημοσ. 4 Οκτωβρίου 2001 Δημοσ. 4 Οκτωβρίου 2001 Ston tomea tou hxou yparxei o gnostos pia se olous osous asxolountai me pshfiakh mousikh PCM (Pulse code modulation) h opos to xseroun allios oi hlektronikoi "diamorfosh shmatos kata palmo", opou enas analogikos palmos metatrepetai se pshfiako dhladh 0 kai 1 toso stous ypologistes oso kai se syskeves hxou (cd player klp). omos toulaxiston gia na metatrepsoume hxo se morfh PCM toulaxiston se poiothta cd apaitountai 10MB dedomenon ana lepto hxou h 172kilobytes/sec kai gia afto to logo xrhsimopoihthike h legomenh symbiesh hxou...<P>h symbiesh hxou ekteleitai apo software odhgous pou onomazontai "codecs" (apo ta arxika compression-decompression), oi opoioi telika "symmazevoun" thn posothta dedomenon gia ton idio hxo arketes fores eos kai 10:1 peripou (sto mp3)...<P>afth th stigmh ena provlhma einai na symbiezoume me tetoio tropo etsi oste na kratame kata to dynaton thn arxikh poiothta tou asymbiestou (PCM) kommatiou kai tou telikou me ton codec pou epilexsame kai sto megalytero vathmo symbieshs!!!<P>mexri kai shmera yparxoun 2 tropoi "symbieshs" pshfiakou hxou... o protos vasizetai sthn ptosh tou bit depth (ths analyshs ton deigmaton). tetoioi codecs einai o ADPCM (adaptive differential pulse code modulation) opu telika katafernei ena logo 4:1 sto arxiko shma kai yparxoun kai oi legomenoi "psyxoakoustikoi" codecs me tous opoioys den peirazetai to bit depth alla afairountai sygkekrimenes akoustikes syxnothtes oi opoies opos lene oi eidikoi "etsi kai allios" den tha akougame se ena synhthismeno xoro! tetoioi codecs einai to mp3 to wma to aac kai alloi polloi!<P>oi gnomes dixazontai kai aftoi pou telika apofasizoun na kanoun to vhma ths symbieshs pshfiakou hxou peftoun sto dillhma: ti einai kalytero na afairethei tmhma tou bit depth (bit depth einai to bathos analyshs sthn metatroph tou analogikou se pshfiako palmo) h na afairethoun akoustikes syxnothtes me ton ena h me ton allo tropo???<P>afhno to erothma se olous osous asxolountai me thn pshfiakh mousikh na poun th gnomh tous!!! (oute ego alhtheia exo peistei akoma telika ti einai kalytero apo ta 2 telika kai me apolyth apopsh!)<P> <p>[ 03-10-2001: Message edited by: gryllos_001 ]
trustfm Δημοσ. 6 Οκτωβρίου 2001 Δημοσ. 6 Οκτωβρίου 2001 mexri kai shmera yparxoun 2 tropoi "symbieshs" pshfiakou hxou... o protos vasizetai sthn ptosh tou bit depth (ths analyshs ton deigmaton). tetoioi codecs einai les : o ADPCM (adaptive differential pulse code modulation) opu telika katafernei ena logo 4:1 sto arxiko shma kai yparxoun kai oi legomenoi "psyxoakoustikoi" codecs me tous opoioys den peirazetai to bit depth alla afairountai sygkekrimenes akoustikes syxnothtes oi opoies opos lene oi eidikoi "etsi kai allios" den tha akougame se ena synhthismeno xoro! tetoioi codecs einai to mp3 to wma to aac kai alloi polloi!<P>Sth deuterh periptwsh mallon eisai la8os ...<BR>Oi psyxoakoustikoi codecs apla de koboun suxnothtes apla DIATHROYN suxnothtes gia perissotero xrono apo ton kanoniko. Sou dinw ena aploiko paradeigma . Kapoios paizei sto piano to NTO gia 5 sec sunexomena alla sto 2o sec pataei kai to Re . To wav kanei deigmatolhpsia suxnothtwn px ana sec opote se ka8e sec 8a elenxe to nto an einai pathmeno... anti8eta to mp3 koita thn DEIARKEIA pathmatos tou nto kai den koita ana sec. Toulaxiston auto exw katalabei egw , Opote den exoume apokoph suxnothtwn . Twra bebaia h xing eggale enan apotuxhmeno codec opou ekane KAI apokoph sunothtas apo 16 khz kai panw (exw kanei o idios grafimata suxnothtwn kai ta xw dei) alla DEN ofeilete ekei h sumpiesh. Auto htan to tragiko la8os ths xing kai gi auto kai apethxe. Alloi codecs ftanoun aneta sta 22 khz opou einai uperarketa akoma kai gia tis pio upshles suxnothtes (lame) alloi pali ftanoun pio katw st 20 khz (blade kai fraunhofer) sta upshla bitrates. <BR>an kanw la8os dior8wse me .<BR>Oso gia thn proth me8odo pou les den thn xerw
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