HDCD revisited.
 

Someone has managed to reverse-engineer HDCD encoding:
http://www.srcf.ucam.org/~cjk32/hdcd

So now it's easy to decode an HDCD to a 24-bit file and see whether
each track has 'Peak Extend' and/or 'Low Level Range Extend'.
Looking at a few (King Crimson) CDs last night, only three had 'Peak Extend'
of which none actually needed it as they wouldn't have clipped anyway.

Any volunteers to correct the Wikipedia entry,
http://en.wikipedia.org/wiki/HDCD ?

--
Eiron.

HDCD revisited.
 

Eiron wrote:

Someone has managed to reverse-engineer HDCD encoding:
http://www.srcf.ucam.org/~cjk32/hdcd

Yup, saw this - decent guy that wrote it, also sent me the source code
so I could build it on NetBSD (which I use for ripping). Compiled
cleanly and works great.

So now it's easy to decode an HDCD to a 24-bit file and see whether
each track has 'Peak Extend' and/or 'Low Level Range Extend'. Looking
at a few (King Crimson) CDs last night, only three had 'Peak Extend'
of which none actually needed it as they wouldn't have clipped
anyway.

The Peak Extend function works spectacularly well when CDs are properly
mastered. Without HDCD decoding:

http://intranet.squirrel-net.co.uk/images/itstime.png

ReplayGained to 89dB, signal off the CD would be normalised to maximum
no doubt.

Now with HDCD decoding enabled, again ReplayGained to standard 89dB
reference level:

http://intranet.squirrel-net.co.uk/i...stime-hdcd.png

LAME can take a 24-bit WAV and dither it back down to 16-bit. The
results speak for themselves. And yes, the difference you can hear is as
spectacular as the difference you can see.

--
Squirrel Solutions Ltd Tel: (01453) 845735
http://www.squirrelsolutions.co.uk/ Fax: (01453) 843773

Registered in England: 05877408

HDCD revisited.
 

Glenn Richards wrote:
Eiron wrote:

Someone has managed to reverse-engineer HDCD encoding:
http://www.srcf.ucam.org/~cjk32/hdcd

Yup, saw this - decent guy that wrote it, also sent me the source code
so I could build it on NetBSD (which I use for ripping). Compiled
cleanly and works great.

So now it's easy to decode an HDCD to a 24-bit file and see whether
each track has 'Peak Extend' and/or 'Low Level Range Extend'. Looking
at a few (King Crimson) CDs last night, only three had 'Peak Extend'
of which none actually needed it as they wouldn't have clipped
anyway.

The Peak Extend function works spectacularly well when CDs are properly
mastered. Without HDCD decoding:

http://intranet.squirrel-net.co.uk/images/itstime.png

ReplayGained to 89dB, signal off the CD would be normalised to maximum
no doubt.

Now with HDCD decoding enabled, again ReplayGained to standard 89dB
reference level:

http://intranet.squirrel-net.co.uk/i...stime-hdcd.png


That is a big difference, but why would they bother to do it that way?
Far easier just to master the whole thing 6dB lower - it certainly won't
be running out of dynamic range at the bottom end. I speak as someone
who owns an Arcam Alpha 9, an HDCD player (very ashamed of myself for
falling for it).

LAME can take a 24-bit WAV and dither it back down to 16-bit. The
results speak for themselves. And yes, the difference you can hear is as
spectacular as the difference you can see.


What do you mean?

d

HDCD revisited.
 

Don Pearce wrote:

That is a big difference, but why would they bother to do it that way?
Far easier just to master the whole thing 6dB lower - it certainly won't
be running out of dynamic range at the bottom end. I speak as someone
who owns an Arcam Alpha 9, an HDCD player (very ashamed of myself for
falling for it).

Two words. Loudness war.

If you master it 6dB lower then it'll be 6dB quieter than everyone
else's CD. And that would never do.

But by using HDCD's Peak Extend you can satisfy the marketing droids at
the record label ("louder is better" etc) without ****ing off people
with decent kit too much.

My DVD player (Arcam DV79) does HDCD decoding and does it rather well.
One of the few DVD players that produces decent audio output from CDs
(whether HDCD or not).

LAME can take a 24-bit WAV and dither it back down to 16-bit. The
results speak for themselves. And yes, the difference you can hear is
as spectacular as the difference you can see.
What do you mean?

On the decoded version the snare drum "snaps" more, the mushyness and
overcompression is all gone.

And yet it's a standard 16/44.1 waveform. Tried encoding to 24-bit FLAC
and couldn't hear the difference between FLAC and 320Kbit MP3 with the
latest version of LAME (playing on a Squeezebox through an Arcam AVR250
via SPDIF).

24-bit has its place in the studio (extra headroom, better S/N ratio)
but I doubt many people can hear the difference on 2 channel stereo with
all that peak limiting and EQ applied. It's a bit like with digital
photography - I use 48-bit mode when doing all the post-processing in
Photoshop but then dither down to 24-bit colour for the final archive
version of the image (usually PNG).

(Disclaimer - I've been staring at a screen all day, hope that paragraph
above makes sense...)

--
Squirrel Solutions Ltd Tel: (01453) 845735
http://www.squirrelsolutions.co.uk/ Fax: (01453) 843773

Registered in England: 05877408

HDCD revisited.
 

Glenn Richards wrote:
Don Pearce wrote:

That is a big difference, but why would they bother to do it that way?
Far easier just to master the whole thing 6dB lower - it certainly
won't be running out of dynamic range at the bottom end. I speak as
someone who owns an Arcam Alpha 9, an HDCD player (very ashamed of
myself for falling for it).

Two words. Loudness war.

If you master it 6dB lower then it'll be 6dB quieter than everyone
else's CD. And that would never do.


But an HDCD disc doesn't play back correctly on a conventional player -
it is actually distorted. When it is played back as intended it is
identical to mastering 6dB lower and allowing the high peaks. So
loudness doesn't come into it.

But by using HDCD's Peak Extend you can satisfy the marketing droids at
the record label ("louder is better" etc) without ****ing off people
with decent kit too much.

My DVD player (Arcam DV79) does HDCD decoding and does it rather well.
One of the few DVD players that produces decent audio output from CDs
(whether HDCD or not).


I've not yet found a DVD player that does a poor job of CDs - what on
earth have you been buying?

LAME can take a 24-bit WAV and dither it back down to 16-bit. The
results speak for themselves. And yes, the difference you can hear is
as spectacular as the difference you can see.
What do you mean?

On the decoded version the snare drum "snaps" more, the mushyness and
overcompression is all gone.


No, I mean about seeing the difference between 24 bit WAV, and 24 bit
dithered down to 16 bit by LAME. I've done this (although not by LAME,
just within a DAW) and as far as visibility goes, there is no difference
- I can't hear one either. Do you mean that LAME does really poor
bit-depth reduction?

d

HDCD revisited.
 

In article , Don
Pearce
wrote:
Glenn Richards wrote:
Don Pearce wrote:

That is a big difference, but why would they bother to do it that
way?

Two words. Loudness war.

If you master it 6dB lower then it'll be 6dB quieter than everyone
else's CD. And that would never do.


But an HDCD disc doesn't play back correctly on a conventional player -
it is actually distorted. When it is played back as intended it is
identical to mastering 6dB lower and allowing the high peaks. So
loudness doesn't come into it.

In addition the "loudness war" has lead people into making CDs with an
effective dynamic range of the order of 1dB or so. Whereas natural music
tends to need about 15dB or more for peak/mean ratios even if we ignore the
normal range of expressive dynamics. I can't see HDCD having much effect on
the driods who produce CDs with such excessively compressed (and clipped)
CDs.

But by using HDCD's Peak Extend you can satisfy the marketing droids
at the record label ("louder is better" etc) without ****ing off
people with decent kit too much.

Alas, the problem may be far too bad for that to work if you are only
offerring 6dB. Also I can't help feeling that the people who apply such
massive compression and clipping are hardly likely to give any thought to
anyone who finds that objectionable. They *know* sic "loudness sells* so
cannae be bothered. Their interest is money, not music.

Slainte,

Jim

--
Change 'noise' to 'jcgl' if you wish to email me.
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Audio Misc http://www.audiomisc.co.uk/index.html

HDCD revisited.
 

"Don Pearce" wrote in message
...
Glenn Richards wrote:
Don Pearce wrote:

That is a big difference, but why would they bother to do it that way?
Far easier just to master the whole thing 6dB lower - it certainly won't
be running out of dynamic range at the bottom end. I speak as someone
who owns an Arcam Alpha 9, an HDCD player (very ashamed of myself for
falling for it).

Two words. Loudness war.

If you master it 6dB lower then it'll be 6dB quieter than everyone else's
CD. And that would never do.


But an HDCD disc doesn't play back correctly on a conventional player - it
is actually distorted. When it is played back as intended it is identical
to mastering 6dB lower and allowing the high peaks. So loudness doesn't
come into it.


This thread really does show how much the lunatics have been allowed to take
over the asylum. We have a perfectly good medium (the CD) with more than
enough dynamic range for any normal music or speech listening requirement.
Yet something called an "HDCD" that does no better a job on a special player
than ordinary CD does on an ordinary player, and a worse one on an ordinary
player, is billed as "better". What is going on?

David.

HDCD revisited.
 

David Looser wrote:
"Don Pearce" wrote in message
...
Glenn Richards wrote:
Don Pearce wrote:

That is a big difference, but why would they bother to do it that way?
Far easier just to master the whole thing 6dB lower - it certainly won't
be running out of dynamic range at the bottom end. I speak as someone
who owns an Arcam Alpha 9, an HDCD player (very ashamed of myself for
falling for it).
Two words. Loudness war.

If you master it 6dB lower then it'll be 6dB quieter than everyone else's
CD. And that would never do.

But an HDCD disc doesn't play back correctly on a conventional player - it
is actually distorted. When it is played back as intended it is identical
to mastering 6dB lower and allowing the high peaks. So loudness doesn't
come into it.


This thread really does show how much the lunatics have been allowed to take
over the asylum. We have a perfectly good medium (the CD) with more than
enough dynamic range for any normal music or speech listening requirement.
Yet something called an "HDCD" that does no better a job on a special player
than ordinary CD does on an ordinary player, and a worse one on an ordinary
player, is billed as "better". What is going on?

David.



Your guess is as good as mine.

d

HDCD revisited.
 

Don Pearce wrote:

If you master it 6dB lower then it'll be 6dB quieter than everyone
else's CD. And that would never do.
But an HDCD disc doesn't play back correctly on a conventional player -
it is actually distorted. When it is played back as intended it is
identical to mastering 6dB lower and allowing the high peaks. So
loudness doesn't come into it.

It's no more distorted than a "loudness mastered" CD would be. The
advantage with HDCD is that there's at least some way to get some
dynamics back, by using the decoder.

I've not yet found a DVD player that does a poor job of CDs - what on
earth have you been buying?

My original DVD player (2nd generation Toshiba SD-2107) was shockingly
bad playing CDs. Worked ok as a transport but the on-board DAC was poor.

My second DVD player (Toshiba SD-100, bought to replace the 2107 that
died) wasn't much better from the analogue outs. The SD-530 wasn't too
bad when playing DVD-Audio discs but wasn't great on CDs. At the time I
was using a Technics SL-PG590 CD player.

One interesting thing I noticed was that the DVD player did a better job
as a transport than the Technics CD player (tested into a Yamaha
DSP-AX620, Arcam Black Box 50 and Arcam AVR250). Using the DVD as a
transport sounded noticably better than the Technics... any ideas?

No, I mean about seeing the difference between 24 bit WAV, and 24 bit
dithered down to 16 bit by LAME. I've done this (although not by LAME,
just within a DAW) and as far as visibility goes, there is no difference
- I can't hear one either. Do you mean that LAME does really poor
bit-depth reduction?

Ah, my fault for posting whilst trying to sort out a client's problem. I
meant the difference between the HDCD and non-decoded versions, whether
24-bit or 16-bit.

--
Squirrel Solutions Ltd Tel: (01453) 845735
http://www.squirrelsolutions.co.uk/ Fax: (01453) 843773

Registered in England: 05877408

HDCD revisited.
 

Don Pearce wrote:

I've not yet found a DVD player that does a poor job of CDs - what on
earth have you been buying?

My old Marantz DVD player did a terrible job of playing CDs.
It missed off the first half second or so of every track.
Other than that it sounds as good as any other CD player,
especially if you know how much it cost.

As for HDCDs, I have one which both uses 'Peak Extend' and needs it.
That's Mark Knopfler's 'Sailing To Philadelphia'. Most of the time the
signal is above -3dB so is seriously clipped without an HDCD decoder.
All the others only venture above -3dB once or twice per track at most
so you wouldn't notice if not decoded.

--
Eiron.