Digital audio

[Chaos - Zdenek Dvorak]

Ide o to, ze mam zaujem si postavit vlastny CD prehravac a chcel by som to
sneikym prebrat. V podstate to mam vymyslene a navrhnute, ale clovek nikdy
nevie ake informacie este moze ziskat. Vzdy je dobry nazor aj ineho. Velmi 
ma
laka AC3 s prepojenim na DVD prehravac. Skusal som neake prepojenia na PDIF
format a chodilo to dobre a monerne som s tym bol spokojny. Malo jediny
problem, bolo to postavene na Philips suciatkach a tie su bud drahe alebo
nedostupne v mensich mnozstvach.
Ak ma niekto zaujem debatovat dalej budem rad. dufam, ze to nie je moc
profesionalna aplikacia pre fsg-news.

[]  prohlizel sis tohle?:
A DSP-based decompressor unit for high-fidelity MPEG-Audio over TCP/IP 
networks
Master's thesis for the M.Sc. Eng. Phys. degree
By öéBjrn Wesn <mailto:bjorn@sparta.lu.se>
At Lund Institute of Technology <http://www.lth.se/> in cooperation with 
Axis Communications AB <http://www.axis.com/> in Lund, Sweden
Supervisors: Stefan Sandström (Axis <http://www.axis.com/>), Mats Cedervall 
(IT/LTH <http://www.it.lth.se/>)

Abstract
Recently, algorithms that can compress audio-signals like music without 
perceptible loss up to ratios around 1:12 have emerged. This makes it 
possible and very feasible to store large amounts of music on comparatively 
small amounts of storage media. It also makes it possible to implement 
realtime playback of music over low-bandwidth computer networks. The goal 
of the thesis was to demonstrate this using dedicated, embedded hardware 
that performs the network accesses and audio decompression without the aid 
of an external computer. The chosen algorithm is MPEG-1/Layer-3, and it has 
been implemented using C and assembler on a Texas TMS320C31 DSP. The 
network access is done usingan Axis NPS570 printerserver, using Axis 
embedded ethernet processor ETRAX. The unit accepts MPEG compressed audio 
over a network using the TCP/IP protocol suite, and feeds it into the DSP 
for decompression and playback.


je k tomu na siti uplne vsechno, vcetne schemat podrobneho popisu a 
zdrojovych kodu. Ten printeserver by asi
sel nejak nahradit (postavit). Klienta TCP/IP - UDP na Atmelu mam napsanyho 
a ted jde jen o fyzicke pripojeni
UTP Ethernetu k jednochipu - to je ale velmi zajimvej ukol, se kterym se 
asi brzo budu muset potykat....
A nebo jeste zajimavejsi by bylo udelat mezixicht na nejakou ATAPI CDromku. 
To tady ale tusim uz nekdo dela.
A pak vymyslet nejakej rozumnej "standart" pro format toho CDcka, aby to 
bylo vhodne sem, ale slo to i na PC,
Teda asi zachovat CDFS, mozna ho nejak rozsirit. Pocitat i s tim, ze u toho 
muze byt displej na ktery se muze psat
info o skladbach atd. A melo by to umet i bezny audioCD. Ale mozna nekdo, 
kdo je in to ma uz vymyslene.

										bye zdvorak@hw.cz


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