HDCD: Does anyone know how to decode it

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hanzablast

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Joined 2014
Hi, I've finished building a high quality DAC with it's own digital filter (in an fpga) and would like to decode HDCD. I've found all the patents, but they don't show how the exact encoding on the cd is done.

Does anyone have the exact encryption of the 'silent code' (what prbs is used, and how the command structure looks like) and the peak/low end extension functions (characteristics)? It must exist somewhere, but I cannot find it up till now.

Thanks for your help!

Hans R
 
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Eldam

Banned
Joined 2012
Hi maybe in the HDCD opensoftware plugins for soft like Foobar, as it's open you can read the code and extract it ?

Maybe a fellow like Soundcheck which use Linux and all its subtilities with audio know the place where you can find what you are looking for ?
 
E

Eldam

Banned
Joined 2012
Oh Yes, are you saying that HDCD is patented and can be only found in chips like the old excelent Pacific ones (out of stock nowadays ?) ?

Few days ago I saw on Foobar.org some plugins to read HDCD with Foobar. So my meaning is we are in open Linux world here and if you understand the code of the HDCD plugin ( which is free to obtain I suppose) you can program the DSD Sharc (not in Linux but abstract the datas of HDCD codec?).

Do you mean you need the reader (if non having the original disc recording in HDCD) and a HDCD chip before the DAC chip even in DIY (without paying the patent when you buy a Pacific Microsonics chip ?)

I supose than if you are able to read from a computer that means you was able to read it then rip it in wav, flac.... and then maybe no need of the decoder (soft or chip) in the electronic side of the DAC ?

Please, what do you wanted to mean Northstar ?
 
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Eldam

Banned
Joined 2012
Please don't tell me what is a ?... just give up that !

I was more focusing of the sense behind it and try to understand the meaning of Microsoft with Microsonics... you make short I understood you wanted highlight something with a word-game !

Yo know sometimes a big ? is more powerfull than ?² x ?²....
 
E

Eldam

Banned
Joined 2012
Pfffffffff,

You seem to adore judging people, make lessons... too bad. Just asked humble questions to you.

Well I am happy you understand after your bad : "hé you can not read, bla bla what I wrote bla bla, it's a "?" bla bla" .... that you was not invited to be associated with me !:hohoho:
 
NorthStar

NorthStar

Member
Joined 2012
Eldam, je m'excuse d'avoir ete direct avec toi. Je suis sur que t'es un bon gars.
Il y a beaucoup de choses que je ne sais pas, et ma question etait "genuine".
Il n'y avait absolument rien d'autre en arriere.

* Reference Recordings' recording engineer Professor Keith O. Johnson, the inventor of the HDCD processing (encoding and decoding) would be the perfect person for answering the OP's original question. ...If he wants to make it available that is.
 
E

Eldam

Banned
Joined 2012
NorthStar said:
Eldam, je m'excuse d'avoir ete direct avec toi. Je suis sur que t'es un bon gars.
Il y a beaucoup de choses que je ne sais pas, et ma question etait "genuine".
Il n'y avait absolument rien d'autre en arriere.

* Reference Recordings' recording engineer Professor Keith O. Johnson, the inventor of the HDCD processing (encoding and decoding) would be the perfect person for answering the OP's original question. ...If he wants to make it available that is.
Click to expand...

Ok Northstar,

Sorry for the missunderstanding. I surely read too fast... and answer too fast as well.
 
E

Eldam

Banned
Joined 2012
The law is the law.... it's too young to be in the public domain. That's maybe why we can saw HDCD free for Foobar... You know with Linux all is open:rolleyes:

it's at your own risk...

PMD100/200 were famous for their "good sound" in the 90s... The slope of their filter seems very good for the ears with low bandwith frequencies DAC...

I read somewhere that EUVL adorred its old AD1865 with a PMD100 chip
 
SY

SY

Ex-Moderator
Joined 2002
SYclotron.com
It looks like the patent expired in 2012. Either way, it's absolutely OK to talk about, experiment with, and post analysis- that's the whole point of patents, to allow knowledge to be shared while maintaining a period of commercialization exclusivity.

Reverse engineering for research or experimental purposes and sharing that info is absolutely legal, unless you have signed an NDA.
 
Ken Newton

Ken Newton

Member
Joined 2003
SY said:
It looks like the patent expired in 2012. Either way, it's absolutely OK to talk about, experiment with, and post analysis- that's the whole point of patents, to allow knowledge to be shared while maintaining a period of commercialization exclusivity.

Reverse engineering for research or experimental purposes and sharing that info is absolutely legal, unless you have signed an NDA.
Click to expand...

Exactly. I don't think this point, about the protection of commercial rights in exchange for spurring further innovation by others, is often understood. Too many engineers seem to be under the impression that a patent forbids building and experimentation utilizing a protected innovation, when patents are actually intended to promote just such activity.
 
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