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Old 29th October 2007, 00:23   #21  |  Link
rasth
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Hi Chris,

Will this help you figure out those transient bits?

I downloaded your files and made a test CD. One Mark Knopfler HDCD song and your 4 test files in this order.

1_Cannibals_08.wav
2_hf_sweep_nf.wav
3_hf_sweep_tf.wav
4_impulse_train_nf.wav
5_impulse_train_tf.wav

I played the CD with RCA SPDIF to a late-90's vintage Parasound DAC1600. The HDCD light came on for all the tracks.

The Parasound has the original PMD-100 chip configured to decode HDCD, oversample 8X and feed the Burr-Brown DACs.

I connected the analog out through a passive volume control. ADCOM SLC-505. Then to the line in input on a PC with NVidia sound chipset. Asus A7N8X-E.

Then I recorded a 24-96 wave file of the line in. If you would like the file , let me know the best way to get it to you. It's too big for email. 26.6 mb compressed with flac. I cut off most of the Knopfler song and left the ending in.
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Old 14th December 2007, 17:21   #22  |  Link
jhsjhs
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Quote:
Originally Posted by cjk32 View Post
Hello all,

I've seen comments from a few people wanting to know how hdcd works, so I decided to take a look at it as an academic exercise.

Attached is a 'reference decoder', which reads a 16-bit wav from from stdin, upconverts it to 24-bit using embedded hdcd information where present, and writes the output to stdout. To use, simply run:

hdcd.exe < 16bit.wav > 24bit.wav

If embedded hdcd information is detected, a notification will be written to stderr. Non hdcd's will also work, although the only result will be to halve their volume.

Let me know how you get on,

Chris
Hi Chris, sorry for this maybe stupid question. Why is there less dynamic (loudness) after converting the wav-files with your really great tool from 16 bit to 24 bit and how can i correct this loss? Rgds, Joerg
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Old 16th January 2008, 15:07   #23  |  Link
sax512
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Hi guys. I'n a new entry on this forum and I posted a thraed where I was looking for information about handling hdcd. Here is the link:

http://forum.doom9.org/showthread.php?t=133756

I resume my questions here:

Can I convert high resolution traks into HDCD?
Can I read HDCD without ripping my flacs, ape or whatever into cds?

Lookink through this thread I noticed that you were speaking about how wmp decodes hdcd. My english isn't so good so I didn't get all the stuff about filters. I think I understood that wmp doesn't decode hdcd in a full and proper way. Am I wrong?

Anyway, I also downloaded hadc.exe but wasn't able to use it. Actually I'm not quite sure what it's for. Is it a player that can decode hdcd? How can I play a track with it?

An last, can I play hdcd with wmp in OsX?

Thanks for your further answers.
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Old 23rd January 2008, 11:08   #24  |  Link
sax512
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can anybody help me with this?

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Old 24th January 2008, 02:33   #25  |  Link
henryho_hk
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I don't know there is any HDCD encoding software around for your raw tracks. For your APE and FLAC, you can decode them into 16-bit WAV and then further decode it into 20-bit WAV (though in 24-bit format) using cjk32's program.
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Old 24th January 2008, 12:27   #26  |  Link
sax512
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Thank you. Actually Ihavent been able to make hdcd.exe to work. I downloaded it but when I open it there's just a black screen. I'm not so skilled with programs so if someone can explain me precisely how to use it that would be great..
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Old 25th January 2008, 06:05   #27  |  Link
henryho_hk
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That's because HDCD.exe is a command-line program without graphical user interface.
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Old 25th January 2008, 12:59   #28  |  Link
sax512
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I would have guessed, but how can I use it? It's the first time I'm dealing with something like this...
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Old 29th January 2008, 23:51   #29  |  Link
bertox
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Oh, cjk32 thank you very much for this app !!! Yeeaaahhh!!!! This is the REAL thing.

Now my King Crimson HDCD stuff sound as it should be.
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Old 30th January 2008, 00:05   #30  |  Link
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sax,
We can't just tell you how to use the command line and expect you to be an expert. You have to learn and experiment.

First of, open a new command line by running the cmd command in your Run Dialogue. Then navigate to were the executable that you downloaded is using the command "cd ..."

Like
Quote:
cd "Documents and Settings/you/Desktop/"
and then type the HDCD decoder executable name, like

hdcd.exe

or something like that. It should be pretty self explanatory from there.
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Last edited by Adub; 31st January 2008 at 22:46.
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Old 30th January 2008, 00:34   #31  |  Link
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yes. my config:

put the source file in the same folder and write (in command line, Merlin7777 following) this:

hdcd.exe -o outputfile.wav sourcefile.wav

- ALL NAMES WITHOUT SPACES BETWEEN WORDS -
- SOURCE AND OUTPUT FILE NAMES MUST BE DIFFERENT -

quite simple.

example: D:\Docs\MY Music\HDCD\hdcd.exe -o whereismybrainRESTORED.wav whereismybrain.wav

Ah! If the app shows "HDCD not detected" alert, means that you source file IS NOT HDCD CODED.

I'LL RECOMMEND an "Microsuck" app called PowerToys, which give you a "direct from any folder you chose" with your right click button Command Line function.

good luck.

Last edited by bertox; 30th January 2008 at 00:39.
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Old 1st February 2008, 13:23   #32  |  Link
sax512
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Thank you. I'll try to make it work.
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Old 1st February 2008, 19:41   #33  |  Link
bertox
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You're welcome. Put here your results please.
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Old 3rd February 2008, 13:04   #34  |  Link
sax512
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Hi there. I had been able to decode with this program. It's very simple once you do it for the first time. I wonder how it can decode the 24 bits out of a 16 bit wav if hdcd is property of microsoft. Maybe Chris can answer this question. I'm wondering also if when it comes to listening from an HDCD with WMP or listening to the same cd encoded as a 24 bit wav there is any difference. That brings me back to the question I made about the post when it's said that WMP does something with filters which I couldn't understand complitely. The post is this:


Quote:
Originally Posted by cjk32 View Post
HDCD allows the use of three features: peak extend, gain adjustment and reconstruction filter switching. Windows media player supports peak extend and gain adjustment, and it has hence been possible to fully implement these features.

Filter switching, however, only makes sense when you are upsampling, something which wmp doesn't do, and there's hence no reference to implement it from. Investigation of various test CDs and various (usually contradictory) literature has led to the conlusion that there are only two filters available at playback, the normal filter and the transient filter.

The reason for this conlusion is that of the three bits of each hdcd code remaining after peak extend and gain adjustment, wmp abandons two, but explicitly stores the remaining one (suggesting that this is the only important remaing bit, giving only two options).

An ivestigation of when this bit was set was what lead to the conclusions that it is intended to cover transients. If you take a look at,

http://www.srcf.ucam.org/~cjk32/hdcd...3%20Panama.PNG

the right channel is untouched, and the left channel shows that value of this remaining bit. It is set to for a period covering each of the drum beats, and similar behaviour is observed with many other tracks.

The intention is to try to add upsampling to the code once the filter's responses are known. I'm hoping that someone with a hardware HDCD decoder (which should be upsample and switch filters) will be able to play the following test tracks through it to ascertain the impulse / frequency response,

http://www.srcf.ucam.org/~cjk32/hdcd/transient_filter/

These are a frequency sweep and an impulse train with hdcd codes embedded to either enable the normal or trainsient filter (_nf.wav, _tf.wav). If anyone does have a go with these, please don;t put the impulse train through speakers (or amp?), I can't imagine it'll do them any good.

Chris
So the final question is: can hdcd or WMP decode HDCD with the same bits of an hardware HDCD decoder?

Thanks.

Last edited by sax512; 3rd February 2008 at 13:09.
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Old 5th February 2008, 22:54   #35  |  Link
sax512
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Anybody knows???
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Old 6th February 2008, 03:47   #36  |  Link
bertox
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The answer is : yes.

But, there are some things that i'm not understanding yet when i decoding with HDCD soft decoder....

I try to talk to cjk32 via PM but not answer mis questions...

Seems that this app is abandoned at all...
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Old 6th February 2008, 20:08   #37  |  Link
sax512
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Yes, I tried to send a PM too but didn't reply. However it's good to know that it's so, even if I still don't understand how it can work.
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Old 7th February 2008, 12:54   #38  |  Link
cjk32
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Originally Posted by sax512 View Post
Yes, I tried to send a PM too but didn't reply. However it's good to know that it's so, even if I still don't understand how it can work.
Hi All,

I've not abandoned the app, just been rather busy lately, and as I've not logged in here, I've not picked up any of the private messages. Hopefully, by the middle of next week I'll have some more free time, and will go through and address all the point accumulated in the thread.

For future reference, you're probably best contacting me via email, cjk32@cam.ac.uk.

Regards,

Chris
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Old 7th February 2008, 16:19   #39  |  Link
bertox
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thank you....after all..
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Old 5th March 2008, 06:47   #40  |  Link
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Quote:
Originally Posted by cjk32 View Post
Hi All,
I've not abandoned the app, just been rather busy lately, and as I've not logged in here, I've not picked up any of the private messages. Hopefully, by the middle of next week I'll have some more free time, and will go through and address all the point accumulated in the thread.
Chris
Thank you for your effort, Chris.

Can you improve the program by let it accept parameters so people can make front-end for it?

Command line is clean and simple, but some of the user may prefer drag and drop (like the famous LAMEdrop), it'll be much easier for them.

Once again, thanks for sharing the program with us.
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