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Extract HDCD, How I Can extract HDCD by software?
SCIF
post Jan 27 2005, 08:34
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How I Can extract HDCD by software(EAC, WMP9...)?
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Garf
post Jan 27 2005, 10:28
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HDCD just uses the standard 16 bit CD Audio encoding, so EAC will rip the "HDCD" part too.

For playback, WMP9 can decode the HDCD.
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PoisonDan
post Jan 27 2005, 10:50
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QUOTE (Garf @ Jan 27 2005, 11:28 AM)
For playback, WMP9 can decode the HDCD.
*

But only from CD, not from the ripped audio files, apparently (according to this post).

More about HDCD here.


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Garf
post Jan 27 2005, 11:44
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Perhaps it could work when you mount the ripped wav with Deamontools.

I was thinking something like Virtual Audio Cable would let you get the HDCD decoded result, but I don't think those tools deal with >16 bit audio which makes them useless for this.
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SCIF
post Jan 28 2005, 03:31
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QUOTE (PoisonDan @ Jan 27 2005, 07:50 PM)
But only from CD, not from the ripped audio files

Is there programm for ripping HDCD in 24/44.1?
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precisionist
post Jan 28 2005, 11:17
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QUOTE (SCIF @ Jan 28 2005, 03:31 AM)
QUOTE (PoisonDan @ Jan 27 2005, 07:50 PM)
But only from CD, not from the ripped audio files

Is there programm for ripping HDCD in 24/44.1?
*


I don't think so, CD is 16bit.
More interesting:
Is there a program able to decode the HDCD info and to convert it to another (hIgher, 32bit float for example) format, and everything in digital way (no analogue step) ?

And what I'm always wondering:
Is HDCD a way to circumvent loudness; does a HDCD played as HDCD sound less clipressed compared to played as CD ?


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SebastianG
post Jan 28 2005, 17:02
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QUOTE (precisionist @ Jan 28 2005, 02:17 AM)
More interesting:
Is there a program able to decode the HDCD info and to convert it to another (hIgher, 32bit float for example) format, and everything in digital way (no analogue step) ?

And what I'm always wondering:
Is HDCD a way to circumvent loudness; does a HDCD played as HDCD sound less clipressed compared to played as CD ?
*


I seriously doubt that this would be worth the effort. Having read the technical infos about HDCD which are publicly available (the AES paper) I currently believe HDCD to be just a technology with quite low benefit compared to plain noise shaping. It's just a thing to make a bit money.

They are claiming 20 bits dynamic resolution. This is actually 16+1+3 bits where approximately one bit is gained via this peak compression and three bits are gained via noise shaping. While playing an HDCD signal WITHOUT a special decoder you'll roughly experience the same signal to noise ratio compared to the output of an HDCD decoder. The peak decompression mechanism which is part of an HDCD decoder is fairly simple, but it won't increase the signal to noise ratio because most of the signal (except the peaks) will get attenuated by 6 dB.

IMHO the best thing would be to leave the format (44 kHz, 16 bit) the way it is. Even without a special wink.gif decoder you will still benefit from the noise shaping part and get roughly 19 bits dynamic resolution.


SebastianG

edit: grammar

This post has been edited by SebastianG: Jan 28 2005, 17:15
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adlai
post Jan 28 2005, 18:00
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I was always under the impression that HDCD was simply a better dithering algorithm.
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SebastianG
post Jan 28 2005, 18:59
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QUOTE (adlai @ Jan 28 2005, 09:00 AM)
I was always under the impression that HDCD was simply a better dithering algorithm.
*


HDCD is:
1) dithering + noise shaping
2) peak compression (kind of a reversible dynamic compressor)
3) hiding commands in some least significant bits of the samples to tell an HDCD decoder which anti-alias lowpass filter it has to use for upsampling

...whereas most of the dynamic range "increase" comes from (1).
("increase" ? yes, it depends on how you measure it. If you perceptually weight the quantization noise the noise power will be lower compared to dithering without noise shaping)


SebastianG

This post has been edited by SebastianG: Jan 28 2005, 19:11
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user
post Feb 1 2005, 11:31
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QUOTE (SCIF @ Jan 27 2005, 08:34 AM)
How I Can extract HDCD by software(EAC, WMP9...)?
*




Yes,

EAC will extract the HDCD bit for bit,
you need a Lossless compression format (wavpack, flac, ape), or the original waves. (see for Lossless extraction www.high-quality.ch.vu - users' audio guides

eg. foobar2000 will play those files perfectly, if you set the bit depth to 16 bit, 24 bit will destroy the readability for an external HDCD decoder like built in amp.
(same for 5.1-dts-wav-CDDA).

If eg. foobar2000 plays the Lossless files, you need a soundcard, which ddoesn't upsample internally from 44.1 to 48 kHZ, and digital output to external hdcd decoder, like in amps.


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ShowsOn
post Feb 1 2005, 13:10
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I just noticed this thread, and given that I finally installed Windows XP last week I thought I would give try the HDCD playback in WMP XP.

I think the only HDCD I own is Pet Sounds by The Beach Boys, the 2001 remastered version.

I went into the devices menu and checked the box "play back audio CDs at 24 bit", is this all that is required to activate HDCD playback? I have a Chaintech 710 sound card set for 2 channel high sample rate mode.

I restarted WMP and when I started to playback the CD the first thing I noticed is that the volume was significantly quieter. Does this mean HDCD playback is working? Is there any other visible way to see that WMP is playing the CD back properly? I'm not really sure if playback sound better, but it is quieter than before I had checked the 24 bit playback box.


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user
post Feb 1 2005, 13:45
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as written above, normally 24 bit playback of audioCds destroys headers, like for HDCD, or 5.1-dts-CD

the HDCD has all information inside its standard 16 bits, the additional informations are stored in least significants bits, maybe inside the 16th.

The wmp player should show "HDCD" if it recognized a HDCD.
iirc, previous wmp version showed hdcd, but didn't decode ?
is it safe now, that wmp decodes HDCD ?

A safer way is,
as written above, play HDCD by foobar2000, 16 bit, and transmit the digital output to an external amp/hdcd-decoder.
which will show u the hdcd logo, if it recognized the true hdcd content an decodes it.

I think, most soundcards don't have such a good analogue output, that u will benefit from wmp hdcd decoding, better to let do the D/A conversion and analogue site of the chain, by external amp.


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precisionist
post Feb 2 2005, 13:26
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QUOTE (ShowsOn @ Feb 1 2005, 01:10 PM)
I restarted WMP and when I started to playback the CD the first thing I noticed is that the volume was significantly quieter. Does this mean HDCD playback is working? Is there any other visible way to see that WMP is playing the CD back properly? I'm not really sure if playback sound better, but it is quieter than before I had checked the 24 bit playback box.
*

Sounds very hopeful. Usually quieter means better.
My question still has not yet been answered. Could it be that mastering engineers 'abuse' HDCD technology to hide a less clipressed version of the audio inside the clipressed one ?


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user
post Feb 3 2005, 12:02
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QUOTE (precisionist @ Feb 2 2005, 01:26 PM)
My question still has not yet been answered. Could it be that mastering engineers 'abuse' HDCD technology to hide a less clipressed version of the audio inside the clipressed one ?
*


No, I don't think, that's possible.
because they have only 16 bits stereo wink.gif
So, they have maybe 15 bits for the CDDA wave, and the 16th, least significant bit contains a digital compressed information, which can only be decoded by HDCD decoder.
So, if you play a HDCD via a normal CDplayer, the 16th bits would be converted by normal DDA-converter to pure noise. (quite silent noise of course, it is the 16th bit...)

bryant (wavpack developer) offered some time ago a tool, which was able to remove the 16th bit with hdcd information. This should enable to ABX hdcd version against the 15 bit CDDA version.
Dunno, where he offered it (at r3mix forum iirc), ask him,
though I should have it somewhere on my HD or a DVD backup.

This post has been edited by user: Feb 3 2005, 12:05


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Pio2001
post Feb 3 2005, 21:25
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QUOTE (user @ Feb 3 2005, 01:02 PM)
QUOTE (precisionist @ Feb 2 2005, 01:26 PM)
My question still has not yet been answered. Could it be that mastering engineers 'abuse' HDCD technology to hide a less clipressed version of the audio inside the clipressed one ?
*


No, I don't think, that's possible.
*



It is possible. Why not ? Since they can play with the dynamics, and choose to have the player enhance it or not.
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precisionist
post Feb 4 2005, 14:23
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QUOTE (Pio2001 @ Feb 3 2005, 09:25 PM)
QUOTE (user @ Feb 3 2005, 01:02 PM)
QUOTE (precisionist @ Feb 2 2005, 01:26 PM)
My question still has not yet been answered. Could it be that mastering engineers 'abuse' HDCD technology to hide a less clipressed version of the audio inside the clipressed one ?
*


No, I don't think, that's possible.
*



It is possible. Why not ? Since they can play with the dynamics, and choose to have the player enhance it or not.
*


Then, again:
Is there a software (or any other way besides a digital-analogue-digital process), allowing me to convert HDCD to 20bit (or better) (or maybe only quieter 16bit) ?


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SebastianG
post Feb 4 2005, 16:34
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QUOTE (precisionist @ Feb 4 2005, 05:23 AM)
Then, again:
Is there a software (or any other way besides a digital-analogue-digital process), allowing me to convert HDCD to 20bit (or better) (or maybe only quieter 16bit) ?
*


To fully benefit from the HDCD encoded informations you have to convert the PCM stream to 88,2 kHz @ 24 bits. But I guess you only want to reverse the optional "peak compression" thingy which won't require upsampling. However, I don't think it'll be worth the effort. (!)

Is there a software ? Possibly. I don't know.
Is there a way ? Sure! Theoretically.
Does it make sense ? IMHO not.


SebastianG

This post has been edited by SebastianG: Feb 4 2005, 16:36
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Pio2001
post Feb 4 2005, 23:29
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No software, exept maybe the combination of Windows Media Player with something like Total Recorder.
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precisionist
post Feb 7 2005, 17:01
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QUOTE (SebastianG @ Feb 4 2005, 04:34 PM)
Does it make sense ? IMHO not.
*

Depends on your personal priorities...In my opinion, 'manual SBR' wasn't worth the effort... wink.gif (I listened to those samples.)
Anyway, thank you for your help. smile.gif


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krabapple
post Feb 8 2007, 19:15
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QUOTE (Pio2001 @ Feb 4 2005, 17:29) *
No software, exept maybe the combination of Windows Media Player with something like Total Recorder.



just to resurrect this from the dead (because I've been playing with HDCD + Total Recorder) TR allows a max PCM recording format of 48 kHz/16 bit. So if 88/24 is really required for proper PCM capture (as per SebastianG) , TR isn't the answer.

I've approached this repeatedly but am still not quite certain how to do a proper HDCD decoded vs nondecoded data (not listening) comparison. I'd like to be able to compare .wav data using soemthing like Audition. I've tried redigitizing the analog output from an HDCD-decoding player, and comparing it to the same file ripped, but in the end I'm not sure what I'm looking at. Flat-topped peaks seem to go away but I'm not sure that isn't just due to capturing an analog output.

And btw I can't for the life of me get WMP 11 to recognize an HDCD (i.e., show the HDCD logo). Anyone succeeded with this?

This post has been edited by krabapple: Feb 8 2007, 19:21
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Eric Carroll
post Feb 26 2007, 06:56
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There has been a long running thread on the Slim Devices Audiophile forum where we have been working to decode HDCDs so we could play them back on our Squeezeboxen and Transporters. Best to read the thread backwards, its now 11 pages long!

We have reached the point where we definately have made progress. Using Windows Media Player 9, we can get the HDCD icon to light up, and we have successfully recorded bits using the Chronotron WAV Plugin for WMP9 (using a 24b audio card and the 24b option enabled).

The issue at hand is if the plugin is actually recording 20b and writing a 24b WAV (actually its WAVEX format) or just recording 16b and padding zeros to 24b.

The only other alternative I have found to date is to use Virtual Audio Cable (VAC) to see if it gets the same result as the plugin or something different. I have not yet tried this option.

If there is someone here who really understands HDCD, what is the expected result when comparing a 16b rip to a 24b WAV capture via WMP9? What should the waveforms look like if the decoder worked and the plugin actually captured 20b? Personally I would have expected increased dynamic range in accordance with the increased bit depth, and an unwinding of any range compression. So I should see spikier peaks and higher peak to average. Yes?

Here is my comparison of the 16b rip and the 24b capture:
The 16b rip is the trace on top and the 24b is the trace on the bottom. Closer inspection shows the peaks in the 24b capture are exactly 6dB down from the 16b capture. However, the peak to average seems about the same, thus the dynamic range did not increase. This suggests we don't actually have the HDCD decode captured.

This post has been edited by Eric Carroll: Feb 26 2007, 07:03
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markanini
post Feb 27 2007, 01:40
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Wow, I wish I knew about this plugin before.
Finally I can automatically extract HDCD info!

@Eric Carroll:
All HDCD titles don't use peak extension, try some other titles.

This post has been edited by markanini: Feb 27 2007, 03:05
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Eric Carroll
post Feb 27 2007, 04:42
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QUOTE (markanini @ Feb 26 2007, 19:40) *
Wow, I wish I knew about this plugin before.
Finally I can automatically extract HDCD info!

@Eric Carroll:
All HDCD titles don't use peak extension, try some other titles.


Glad to help on the plugin... It still means you have to play the whole song in real time...

But we have two users who seperately captured via the plugin and all we saw was a decrease in peak levels.

I only have one HDCD that I know of... I was doing this as an experiment, hoping to get to ABX the before 16b and after 24b to see if it was worth buying more. While we have put alot of work in on this, we haven't yet gotten to the "is the difference audible" stage yet...

If you have some HDCDs, could you try doing a 16b rip, then a 24b capture and compare them in Audacity to see what result you get?
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markanini
post Feb 27 2007, 05:26
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QUOTE (Eric Carroll @ Feb 27 2007, 05:42) *
Glad to help on the plugin... It still means you have to play the whole song in real time...

Not if you tick "Disable audio output(fast recording)". wink.gif

I will upload some waveforms as soon as I have the time.
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markanini
post Feb 27 2007, 06:31
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Since I got too excited about this, here are the waveforms:

Sound Chaser from Yes - Relayer


The WMP output gave an extra 6 dB headroom, no more shaved peaks smile.gif

Sister Andrea from Mahavishu Orchestra - Lost Trident Sessions


I amplified the waveforms for this song to the same relative volume.
This didn't get as much peak extension as the other title, but still a good 3 dB increase in dynamics.
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