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Topic: Question about HDCD (Read 22676 times) previous topic - next topic
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Question about HDCD

HDCD should sound better than normal cd when played with cd player that can decode HDCD but what about beeing played with standard cd player?
I read somewhere that an HDCD played with a standard cd player lose 1 or 2 bit (these bit are used for HDCD capable drive to decode the additional 4 bit)
Is it true?  If so, will I achive better quality by decoding the HDCD with a capable software to a 24bit wav and then convert it to a 16 bit with dithering?
Sorry for my bad English...

Question about HDCD

Reply #1
You don’t really lose 1-2 bits when using a non-HDCD decoder because the HDCD trigger uses only the LSB and is active for only about 1% of the time. I don’t think that could ever make a difference.

However, there is some dynamic range compression that does not get reversed when you play without a HDCD decoder, and so I would say that if you want the playback to sound as intended you would want to do what you suggest to get a new 16-bit version (if you can’t just use the 24-bit version).

Question about HDCD

Reply #2
Thanks for your answer, I also noticed that HDCD are 6 dB lower in volume, so increasing the volume by 6 dB in the 24 bit file before the conversion with dithering to 16 bit make sense

Question about HDCD

Reply #3
HDCD should sound better than normal cd when played with cd player that can decode HDCD


well, that's the *claim*, anyway.  It's kind of hard to compare HDCD-encoded versus not HDCD-encoded  versions of the same master -- HDCDs don't tend to include two versions -- and thus hard to verify.

Also, there's several optional settings available to HDCD mastering, e.g. Peak Extension.  Hard to know if an audible difference is due to THAT versus HDCD encoding per se.



Quote
but what about beeing played with standard cd player?


It's supposed to still sound better by virtue of the high-quality ADC used for HDCD mastering.  Or something like that.

Quote
I read somewhere that an HDCD played with a standard cd player lose 1 or 2 bit (these bit are used for HDCD capable drive to decode the additional 4 bit)
Is it true?  If so, will I achive better quality by decoding the HDCD with a capable software to a 24bit wav and then convert it to a 16 bit with dithering?
Sorry for my bad English...


If you can't feed the CD signal to a decoder, you'll get closer to what the mastering engineer intended by archiving as software-decoded files.  Typically these end up as '24 bit' files  (though they 'measure' as 20 bit via Adobe Audition analysis).
Why convert to 16 bit?

Please realize that for many HDCDs, software decoding simply renormalizes the track to peak at  -6dBFS or so (there was a bit of a kerfuffle about this back when anyone cared about HDCD -- HDCD players also reduced 'plain' CD playback level by that amount, in order not to give them a sonic advantage.  Some folks didn't like that). Given that,  the only utility I've seen for HDCD decoding is if Peak Extend is present -- in that case, the extra headroom is actually used.  So it's a good idea to run hdcd.exe in the 'info' mode, to see which discs/tracks actually have Peak Extend enabled.

Another option of HDCD mastering, Transient Filter Switching (or something like that) has never, AFAIK, been implemented in playback software.  I'm not persuaded it would make much audible difference if it was, whereas Peak Extend can add a few dB to 'dynamic range' (crest factor), conceivably audible.

Question about HDCD

Reply #4
Thanks for your answer, I also noticed that HDCD are 6 dB lower in volume, so increasing the volume by 6 dB in the 24 bit file before the conversion with dithering to 16 bit make sense

Not all are. Imho decoding and dithering back only is worth with HDCDs using real Peak Extension. bryant mentioned it. On some it is shown as used but it it doesn´t change the peaks, at least the parts i checked. Some decode to permanent 17bits but with a volume below -6dB, so shifting it up +6db gives exactly 16bit. In this case i suppose the HDCD mastering machine applies its kind of dither, not more. Not worth to fiddle with these.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Question about HDCD

Reply #5
Thanks for your answer, I also noticed that HDCD are 6 dB lower in volume, so increasing the volume by 6 dB in the 24 bit file before the conversion with dithering to 16 bit make sense

Not all are. Imho decoding and dithering back only is worth with HDCDs using real Peak Extension. bryant mentioned it. On some it is shown as used but it it doesn´t change the peaks, at least the parts i checked.


? I've never seen that.  Anywhere I've seen PE used, there was an obvious difference in a waveform comparison to non-decoded (actual 'extended' peaks, not just renormalization)


Question about HDCD

Reply #6
Thanks for your answer, I also noticed that HDCD are 6 dB lower in volume, so increasing the volume by 6 dB in the 24 bit file before the conversion with dithering to 16 bit make sense

Not all are. Imho decoding and dithering back only is worth with HDCDs using real Peak Extension. bryant mentioned it. On some it is shown as used but it it doesn´t change the peaks, at least the parts i checked.


? I've never seen that.  Anywhere I've seen PE used, there was an obvious difference in a waveform comparison to non-decoded (actual 'extended' peaks, not just renormalization)

Think it was on my Oldfields. Sometimes the "low level range extend" kicked in but never the "peak extend"

btw,. here is an article with much infos but also lots of marketing hype.
http://mixonline.com/mag/audio_pacific_microsonics_hdcd/
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Question about HDCD

Reply #7
This is what hdcd tells me about the hdcd file I decoded:

Packets Processed              : 29385
Peak extend                    : Never enabled
Minimum gain                  : 0.0dB
Maximum gain                  : 0.0dB
Transient filter (Unsupported) : Enabled intermittently

What does unsopported means in transient filter? It's present in my hdcd wav but not decoded?

Question about HDCD

Reply #8
This is what hdcd tells me about the hdcd file I decoded:

Packets Processed              : 29385
Peak extend                    : Never enabled



So, no peak extension


Quote
Minimum gain                  : 0.0dB
Maximum gain                  : 0.0dB
Transient filter (Unsupported) : Enabled intermittently

What does unsopported means in transient filter? It's present in my hdcd wav but not decoded?



Yep. 

I wouldn't bother decoding this track.

Question about HDCD

Reply #9
Thanks for your answer, I also noticed that HDCD are 6 dB lower in volume, so increasing the volume by 6 dB in the 24 bit file before the conversion with dithering to 16 bit make sense

Not all are. Imho decoding and dithering back only is worth with HDCDs using real Peak Extension. bryant mentioned it. On some it is shown as used but it it doesn´t change the peaks, at least the parts i checked.


? I've never seen that.  Anywhere I've seen PE used, there was an obvious difference in a waveform comparison to non-decoded (actual 'extended' peaks, not just renormalization)

Think it was on my Oldfields. Sometimes the "low level range extend" kicked in but never the "peak extend"



? Here's how mine read.

Code: [Select]
Mike Oldfield    1974 - Hergest Ridge    01 - Hergest Ridge Part One.wav         HDCD detected   Peak extend   : Enabled permanently 
Mike Oldfield    1974 - Hergest Ridge    02 - Hergest Ridge Part Two.wav         HDCD detected   Peak extend   : Enabled permanently
Mike Oldfield    1975 - Ommadawn    01 - Ommadawn Part One.wav         HDCD detected   Peak extend   : Enabled permanently  
Mike Oldfield    1975 - Ommadawn    02 - Ommadawn Part Two.wav         HDCD detected   Peak extend   : Enabled permanently
Mike Oldfield    1990 - Amarok    01 - Amarok.wav         HDCD detected   Peak extend   : Not enabled



HDCD.exe only samples the first few seconds of a track, to gather info.  IIRC, HDCD encoding actually stops for the final 'Horses' part of Ommadawn.

Question about HDCD

Reply #10
Mike Oldfield   1975 - Ommadawn   01 - Ommadawn Part One.wav       HDCD detected  Peak extend  : Enabled permanently

Take that one for example and look at its bit usage. It uses 17 bits all the time and has a maximum peak at -6.6db.  Now where should the real expansion be?
Of cause you can up the volume now by 6.6db and dither back to 16 bits but i don´t know we gain much here.
Somewhere at hydrogen i offered a Yim Hok Man sample that makes real sense.

Edit: Found the Link http://www.hydrogenaudio.org/forums/index....showtopic=61733
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Question about HDCD

Reply #11
Mike Oldfield   1975 - Ommadawn   01 - Ommadawn Part One.wav       HDCD detected  Peak extend  : Enabled permanently

Take that one for example and look at its bit usage. It uses 17 bits all the time and has a maximum peak at -6.6db.  Now where should the real expansion be?
Of cause you can up the volume now by 6.6db and dither back to 16 bits but i don´t know we gain much here.



Yeah, looking at it, the waveform of that one doesn't look so 'extended', so you might be right.  What are the peak/avg level values with and without decoding?

Question about HDCD

Reply #12
I won´t go deeper into that. There might be tiny differences burried deep at low level. Most likely never to abx. Of cause there are many CDs that make more use of real Peak Extension. You wanted to know were not. Much fun in digging deeper!
Even thinking about when the differences are so tiny we can do even more harm when dithering back to 16bit as if we left it alone. Playing it back with 24bit may be ok but can be a waste.

I left these Oldfields alone.

Edit: I think i dropped some parts into Audio Diffmaker back then and decided it is not worth.
Is troll-adiposity coming from feederism?
With 24bit music you can listen to silence much louder!

Question about HDCD

Reply #13
HDCD should sound better than normal cd when played with cd player that can decode HDCD but what about beeing played with standard cd player?


HDCD is yet another example of the fallacy of not addressing the weakest link in the recording chain which is the space that the recording is made in. 

To this day, including the use of so-called hi rez formats, there are no known examples of commercial recordings whose actual program materal exceeds 90 dB. This is due to the practical limiations of recording real music in real spaces.  Of course any recording engineer who wants to can amplify a signal to 0 dB FS and then do an electronic fade out to -144 dB if he works with 24 bits.

But back in the real world, if you bang a gong in a real room you might generate a tone burst that peaks at 110 dB SPL, and you can let it fade into the background noise in the room, but the background noise in the room will still be at least about 20 dB SPL and there you are, 90 dB dynamic range.

HDCD was an example of a solution that looked for a problem for well over a decade and never actually found it!

DVD-A and SACD were the sequel examples of the same thing. Some tell us that they are still looking for a problem to solve, but what I see is 2 more  dead or dying formats that never captured the interest of mainstream music lovers. They failed because they did not convince enough people of their sonic superiority.

Dolby TrueHD seems to be the latest repackaging of the DVD-A/SACD concept.

Question about HDCD

Reply #14
I think the advantages of having an higher bit depth is not only related to an higher dynamic but also to an higher precision in representing the information...

As regards HDCD I own an Audio Fidelity CD that doesn't have peak extension... I bit-compared wav from the hdcd decoded 24 bit wav (with a gain of 6 dB) to the 24 bit wav file I got disabling hdcd decoding (since the file is 16 bit the conversion to 24 bit will add 8 zeros padding bit).
These 2 wavs are EQUAL... so there's NO DIFFERENCE AT ALL using hdcd.exe with file without peak extension (unfortunately, as said before, transient filter can't be decoded by the software)

By the way... Can anybody suggest me some hdcd album that uses peak extension?

Question about HDCD

Reply #15
I think the advantages of having an higher bit depth is not only related to an higher dynamic but also to an higher precision in representing the information...
The question is "Is that really audible?" And HDCD doesn´t use a higher bit depth - they fake it. Having said that, they only sound the way they were intended when decoded - especially with peak extension.

By the way... Can anybody suggest me some hdcd album that uses peak extension?
Almost all releases from Reference Recordings use Peak Extend. Also some scores from Alan Silvestri from the mid ´90s to the early ´00s. There are some mainstream albums out there also - from the Dire Straits, Mark Knopfler or Neil Young. But you are really stepping into the dark when you want to find out something like this.
marlene-d.blogspot.com

Question about HDCD

Reply #16
DVD-A and SACD were the sequel examples of the same thing. Some tell us that they are still looking for a problem to solve, but what I see is 2 more  dead or dying formats that never captured the interest of mainstream music lovers. They failed because they did not convince enough people of their sonic superiority.

Dolby TrueHD seems to be the latest repackaging of the DVD-A/SACD concept.


DVD-As, SACDs, TrueHD/ DTS HD-MA all offer something that CDs and HDCDs don't.  Something that is easily tangible, next to impossible to ABX incorrectly, and to many listeners is a huge increase in quality: 6 Channel sound.  As for the higher sampling rates/ bit depths/ etc, I will make no claim as to whether or not they help.  But there is certainly lots of room for it on their format, so why not?  Doesn't really hurt.

Those formats probably didn't catch on because of either the timing of when they came out (when DVDs were still reasonably new and they required special DVD players to play and a 5.1 system to benefit from, 2 things that are much more common now than then), or because they couldn't be used to any extra effect when put on a stereo portable player.

Question about HDCD

Reply #17
Dolby TrueHD seems to be the latest repackaging of the DVD-A/SACD concept.


I'd disagree with that. I don't believe we've ever had a lossless 5.1 surround format available in the consumer market? CD has been around for many, many years but for surround we've just had the multi-channel equivalent of MP3?

Just because you can get Dolby TrueHD and DTS-MA soundtracks with 24-bit 96KHz audio I don't see it as the same thing. You can also find BR discs with 16-bit 48KHz 5.1 surround but it's lossless.

Just my feelings anyways but I guess this is a separate discussion so sorry to the OP!

Question about HDCD

Reply #18
Dolby TrueHD seems to be the latest repackaging of the DVD-A/SACD concept.


I'd disagree with that. I don't believe we've ever had a lossless 5.1 surround format available in the consumer market? CD has been around for many, many years but for surround we've just had the multi-channel equivalent of MP3?


DVD-A and SACD both are "lossless" 5.1 formats that can do 24-bit 96kHz.

As far as formats for on computer, multichannel FLAC has been around for a while at least.

Question about HDCD

Reply #19
I think the advantages of having an higher bit depth is not only related to an higher dynamic but also to an higher precision in representing the information...

As regards HDCD I own an Audio Fidelity CD that doesn't have peak extension... I bit-compared wav from the hdcd decoded 24 bit wav (with a gain of 6 dB) to the 24 bit wav file I got disabling hdcd decoding (since the file is 16 bit the conversion to 24 bit will add 8 zeros padding bit).
These 2 wavs are EQUAL... so there's NO DIFFERENCE AT ALL using hdcd.exe with file without peak extension (unfortunately, as said before, transient filter can't be decoded by the software)

By the way... Can anybody suggest me some hdcd album that uses peak extension?

Some Rhino releases, Yes and Greateful Dead.

Question about HDCD

Reply #20
Dolby TrueHD seems to be the latest repackaging of the DVD-A/SACD concept.


I'd disagree with that. I don't believe we've ever had a lossless 5.1 surround format available in the consumer market? CD has been around for many, many years but for surround we've just had the multi-channel equivalent of MP3?


Even DVD-Video supported multichannel audio:

DVD FAQ

Quote
Audio details of DVD-Video

...

Linear PCM is uncompressed (lossless) digital audio, the same format used on CDs and most studio masters. It can be sampled at 48 or 96 kHz with 16, 20, or 24 bits/sample. (Audio CD is limited to 44.1 kHz at 16 bits.) There can be from 1 to 8 channels. The maximum bit rate is 6.144 Mbps, which limits sample rates and bit sizes when there are 5 or more channels. It's generally felt that the 120 dB dynamic range of 20 bits combined with a frequency response of around 22,000 Hz from 48 kHz sampling is adequate for high-fidelity sound reproduction. However, additional bits and higher sampling rates are useful in audiophile applications, studio work, noise shaping, advanced digital processing, and three-dimensional sound field reproduction. DVD players are required to support all the variations of LPCM, but many subsample 96 kHz down to 48 kHz, and some may not use all 20 or 24 bits. The signal provided on the digital output for external digital-to-analog converters may be limited to less than 96 kHz and less than 24 bits.


As others have observed, both DVD-A and SACD supported lossless (uncompressed) multichannel audio.

So, we've had lossless multichannel audio on consumer media (DVD-V)  since the late 1990s.

Question about HDCD

Reply #21
Quote
So, we've had lossless multichannel audio on consumer media (DVD-V) since the late 1990s.


Well I never knew that, the format actually supports multi-channel lossless but I've never seen it used on DVD-V before  I guess because it's uncompressed and takes up so much space there'd be little room for video!

Thanks for the info!

Question about HDCD

Reply #22
Quote
So, we've had lossless multichannel audio on consumer media (DVD-V) since the late 1990s.


Well I never knew that, the format actually supports multi-channel lossless but I've never seen it used on DVD-V before  I guess because it's uncompressed and takes up so much space there'd be little room for video!

Thanks for the info!


Actually it's not usually difficult at all to fit a DVD-A with music videos/live performance with DD 5.1 for each track as well.

Question about HDCD

Reply #23
Quote
So, we've had lossless multichannel audio on consumer media (DVD-V) since the late 1990s.


Well I never knew that, the format actually supports multi-channel lossless but I've never seen it used on DVD-V before  I guess because it's uncompressed and takes up so much space there'd be little room for video!

Thanks for the info!


Actually it's not usually difficult at all to fit a DVD-A with music videos/live performance with DD 5.1 for each track as well.


But not a 2 hour movie at a sensible bitrate

Question about HDCD

Reply #24
I think the advantages of having an higher bit depth is not only related to an higher dynamic but also to an higher precision in representing the information...


These are two ways of looking at the same thing.

Actually it's not usually difficult at all to fit a DVD-A with music videos/live performance with DD 5.1 for each track as well.


But LPCM 5.1 (lossless), that we are talking about, uses 8 times more space than DD 5.1 (lossy).