HDCD software decoded

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DewDude420
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HDCD software decoded

Post by DewDude420 »

Before you wonder...no..I didn't do this with Goldwave, but I thought I'd share it with some of the audio people here.

I found out that, for the last few months, a command-line HDCD decoder has been in existance..in addition to a wav-output for windows media player..which also has HDCD decoding.

If anyone doesn't know what HDCD is..it's a system by which a spcial dithering and dynamic compression system is used during the mastering process. When played back normally, you get a dynamically compressed liner PCM decode (which is like any audio CD these days). When done through HDCD, you get, they claim, 20-bits of resolution. So it does some sophiscated expansion process to restore original dynamics, along with peak extenders and transient filters (which is disabled in the cli tool).

So, I've got a couple HDCD's and I ran them through to see what they'd sound like...here's a screenshot from Very Best of Dire Straits, which is HDCD. Both files have been maximized to -1db.

Image
Last edited by DewDude420 on Wed Nov 28, 2007 6:21 pm, edited 1 time in total.
Stiiv
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Post by Stiiv »

I have a Brian Eno boxed set that was supposedly mastered in a similar fashion, but years ago....Sony called their process Super Bit Mapping, & they claimed it enabled 20-bit resolution on "regular" CD players. I thought that was BS, frankly. Have you noticed better sound quality with this HDCD format?

BTW - the pic in your post isn't showing up.
Stiiv
DewDude420
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Post by DewDude420 »

ahh...super-bit-mapping. the term that confused consumers everywhere into thinking they were getting a superior product.

in reality..it's half right. super-bit-mapping is essentially just an optimized dithering/noise shaping process used by sony on thier higher-than-16 bit masters for downsampling to compact disc.

one thing i noticed about sony has been..they always seemed to like thier slightly higher resolution ADC's, take for example the MD format about 10 years ago. the componet units (and portables too i believe) had a 20-bit ADC feeding into a 16-bit codec..i'm not sure how it did the downsample, but sony's always one of the first with this stuff.

the entire "20-bit resolution" is somewhat of a misnomer. while super-bitmapped audio is still 16-bit...your ears will percieve the supposed 20-bits of resolution thanks to dithering..which is just a broadband noise signal put in place to help distribute the bits more evenly..which means quiet passages in the music will be clearer and more detailed than if you had just chopped bits off. it's much like Dolby HX Pro on the old tapes..it's an encoding process that doesn't require any special decoding to take advantage of (HX Pro, BTW, stood for Headroom eXpansion..which basically manipulated the tape's biasing signal in accordance to the input signal..so louder signals would get less bias than quiet signals..biasing too is just a high-frequency noise signal placed onto the tape to excite the particles enough to respond to the lower-frequnecy of music, as biasing is somewhere up around 100khz, dithering is much lower...they're two totally different technologies but are somewhat close enough that in my mind, i can equate thier use..maybe that's why i'm eccentric)

HDCD on the other-hand is a encode/decode method.

not much is really known about HDCD other than what's in the whitepapers, which doesn't go into a whole lot of detail. but, essentially, the 20-bit (or higher) masters are processed in such a way that they can be decoded. while i've not gotteh ahold of the whitepapers and have had to rely on the unknown-creditability of others..i can gather a little bit.

first of all, HDCD has an optimized dithering process so the 20-bit audio can be dithered down to 16-bit without much loss in quality...so you've got the first portion of super bitmapping like technology in here, however, there are some differences. HDCD fits in a 16-bit stream..however, one bit is used as a signaling bit for the HDCD decoder, so your audio only has about 15 bits of resolution, with the last bit not really doing much on a straight PCM decode. you lose a little SN ratio (i believe the lowest amplitude sample in a raw HDCD decode i came across was around -90 db), but it's not enough to really notice it. the other half is a companding system. if you listen to an HDCD in raw mode, it will sound a bit more dynamically compressed than the HDCD decoded stream, so, expansion is a part of HDCD's scheme. i'm sure if i really played around, i might be able to get close with a standard expander...but..it's like the time i tried to duplicate Dolby B decoding digitally with an expander...what works good in hardware doesn't always work in software.

i'm willing to bet that a properly mastered super-bit mapped CD will sound about the same to a normal person as an HDCD decoded disc. you're not actually getting any real increase in resolution with either format, not from a technical sense...but you get more of a perceived quality.

i've performed what i dubbed "UltraDithering" on a HDCD decode and the resulting 16-bit sound was just as good. ultradithering is just a process where i upsample the 44.1/24 HDCD (or any other 24-bit source i've got) to 96/24 and apply my dithering at that level..using a 96khz noise shaping, this allows me to get the best dithering possibile without putting the noise-shaping in the audible spectrum..once it's 16bit i can resample/filter to whatever sampling rate i want. there's no increase in quality in upsampling...it just merely allows me to apply noise-shaping in a portion of the spectrum i'm going to discard after it's not needed.

these systems/methods are half-gimmick half serious. while you can't actually get an extra 4 bits of resolution out of the air, you can make it seem like you do, and give people maybe, a feeling thier extra dollars were spent wisely.

i should note that HDCD doesn't just..expand. somehow..i guess by reading the HDCD bits in the audio stream, it's able to match the original compression curve used to expand the audio, it's also got a couple of extra features like peak-expander and transient filter that aren't well understood.

I will say that after running HDCD's through the decoder, i do like the less-compressed result..and even tho it's just expanding the compressed audio...it does it very nicely (a way that, as i said, i can't duplicate with an expander) and i'm much happier with the resulting 24-bit signal, even if it is originally 16-bits.

i think a lot of the improvement has to do in the HDCD processing is done in a 20-bit resolution rather than 16..and you do kind of gain something when you process in a higher resolution than normal.
Stiiv
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Post by Stiiv »

these systems/methods are half-gimmick half serious.
Pretty much as I'd suspected. Friends of mine will argue for hours over the advantages/futility of (home) recording & mixing at, say, 24/96, when the final output ends up as 16-bit anyway. Until the next "real" advance in sound reproduction comes along (& please, God, let it be something that isn't easily ruined by rough handling....I often wonder what the hell they were thinking when Philips/Sony/et al ok'd the cd & dvd 'physical' formats; disks are so fragile, awkward to handle safely, etc. LPs & cassettes look like Superman compared to the Clark Kent-like wimpery of optical disks), my goal will continue to be getting the cleanest, "warmest" master possible at 16-bit, because that's the best reproducible resolution the CD format can provide.
Stiiv
DewDude420
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Post by DewDude420 »

Stiiv wrote:
.I often wonder what the hell they were thinking when Philips/Sony/et al ok'd the cd & dvd 'physical' formats; disks are so fragile, awkward to handle safely, etc. LPs & cassettes look like Superman compared to the Clark Kent-like wimpery of optical disks), my goal will continue to be getting the cleanest, "warmest" master possible at 16-bit, because that's the best reproducible resolution the CD format can provide.
you talk about the "next big thing" in audio..yet you only want 16-bit. 24-bit is here...it is not as mainstream since audio cd's aren't dead....but it is here...it's not going anywhere..it's part of "the next big thing". however, resolution aside, we need to strive for better masters. i seriously don't understand how it could even be REMOTELY acceptable to have ANY clipped samples on a CD.

as far as optical disks....let's face it, an optical disk is a bit more durable than a think plastic PVC platter. if you don't abuse your media in the first place. you don't have the problem. CD's have decent error correction and can withstand some scratches. vinyl LP's offer no help..and cassettes? seriously....reel to reel maybe, cassettes? they're "durable" sure, they've lasted THIS long, but the sound quality leaves a lot to be desired.

it seems for the time being that optical discs are going to be the primary way of distributing music in a retail enviroment. they are cheap to produce and have of capacity for thier size.

in the home market, things are diffently going to go to a hard-disk based medium...maybe even flash memory if it gets cheap enough to compete at a per-gig basis. this is not counting any new technology for storing information we come up with in the future. i personally keep EVERYTHING on a hard drive. my PC is actually a pretty major component in my stereo setup...some people see a $200 sound card and go ack..but the same people might look at a $200 SACD/DVD-Audio/Audio-CD player and go "ooooh"... i look at both and go "ooooh"

plus, let's be honest, having everything at the disposal in a few clicks is better than walls of CD's
DougDbug
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Post by DougDbug »

Friends of mine will argue for hours over the advantages/futility of (home) recording & mixing at, say, 24/96, when the final output ends up as 16-bit anyway.
If you are recording "live", or mixing, 24-bits is a big advantage.... You have more headroom.

At 16-bits, its difficult to get a good strong signal, and yet avoid clipping when you are recording live. So, you end-up recording at a fairly-low level. (If you recording from a vinyl record, broadcast, or tape, this is much less of an issue, because the recording is already limited & compressed.)

The same is true when mixing. When you mix several 16-bit tracks, you have to be very careful that the combined levels don't clip. GoldWave uses 32-bit floating-point for temporary processing, so you can mix two or more 0dB signals without clipping, as long as you normalize (maximize) before saving back to 16-bits.

The 96kHz sample rate can theoretically give you more precise effects, but I doubt I could actually hear the difference.
Stiiv
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Post by Stiiv »

you only want 16-bit
Oh, no, let's not get into "what I want". :wink: I'd want 24-bit everything, tomorrow, for free. :D
you talk about the "next big thing" in audio
I was referring to the next dominant "physical medium" on which stored music would be bought & sold....you know, the next step after cd/dvd. Dirt-cheap flash memory would be a great way to go.
i seriously don't understand how it could even be REMOTELY acceptable to have ANY clipped samples on a CD.
Agreed. The sound of digital clipping is IMHO worse than nails on a blackboard. You really have to wonder if anyone actually listened to the master before sending it out for duplication. Re: my mention of the remastered "Raw Power" in the "record warp" thread - my theory is that the Ig either a)still has massive contempt for his audience (his interviews make this seem rather likely), or b)just didn't give a ****, which kinda goes back to a).
an optical disk is a bit more durable than a think plastic PVC platter.
Technically yes, but, oddly I've always found LPs, despite their much larger size, easier to handle safely than CDs. (I can be spazz-tastic sometimes. :wink: ) Another difference: if a CD's top (non-data) side is badly damaged, the whole thing becomes a coaster...at least messing up side A of an LP leaves side B unscathed.
cassettes? they're "durable" sure
That was the only aspect of cassettes I was referring to there.....they do sound pretty awful to 21st century ears.
Doug wrote:If you are recording "live", or mixing, 24-bits is a big advantage.... You have more headroom.
No doubt, Doug....& I look forward to having 24/96 on my next machine. I just can't justify spending money (right now, anyway) on newer equipment whose sonic superiority is almost inaudible on an audio CD. I didn't mean to imply that higher bit & sampling rates don't sound much better....with digital, more & faster are always better. :D

For now, I'm going to keep the highest highs & lowest lows just a hair's breadth away from 0dB, & overall volume be damned! lolol

After all, there's always the volume control on the user's stereo. :wink:

Thanks for the great posts & interesting discussion, guys. 8)
Stiiv
DewDude420
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Post by DewDude420 »

Stiiv wrote: Oh, no, let's not get into "what I want". :wink: I'd want 24-bit everything, tomorrow, for free. :D
amen. i'm working on getting a lot of vinyl into 24-bit...i just keep getting sibilance distortion in s's and t's....i just bought a Shure M44G, still getting it. I think my stylus is defective (like, try tilted)...i need to call and order a new one...an elliptical one..or a shibata.

as far as the physical medium. *shrugs* i'm not as concerned about that because whenever i get my stuff home, first thing i do is back it up to a medium that is much less damagable.

what's interesting about digital clip is...at least with my sound card...i don't get the overall harshness..and i think a lot of that is due to oversampling (or in this case..24-bit crystalizer) in CD players....it just really makes dynamic compression come out.

you're right on the CD's. scratch the top, ruins the disc...plus you CAN put your grubby fingers on an LP if you clean it right after, otherwsie the oil breaks the vinyl down and you've got hand/finger prints that have eaten the vinyl, leaving it pitted

i do have to mention my comment on cassettes was for the majority of pre-recorded offerings that used to be on the market. I do in fact, own several tape decks. My favorite is my Onkyo Integra TA207. 3-head with Dolby B/C and HX Pro and manual bias adjustment. I've created some DAMN good sounding tapes off digital using Type II's and Dolby C. they can sound good, you just really gotta tweak it.

96/24 is actually pretty cheap now-adays. you can get a 96/24 capeable card for what...$99 now? you don't need to go buy a $200 package.

One thing I've noticed about vinyl LP's, the output of my preamp and setting my recording level to 0db in the card leaves me about 7db of headroom..which if a click or something clips like mad..no big deal, i'm removing those samples anyway. i've also found if you do some clever FFT processing and extract the inphase audio (goldwave can't do this), then mono records require much less processing.

It has been good to see a rather nice civilized discussion going on here...i mean, sure, it's a goldwave forum..but talking goldwave all the time does get rather boring and let's face it, we're probably all audio geeks to a degree...

thanks to chris for letting us have these discussions (and possibly more in the future)...i know it's brought me out of obscurity and onto this thing a bit more often.

and for another slightly on-topic discussion...this christmas season it will be 10 years ago that i first found and registered goldwave....it still blows my mind that 10 years later and i've grown from a complete audio noob into what i am now.
Stiiv
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Post by Stiiv »

it will be 10 years ago that i first found and registered goldwave
Isn't that something? Major kudos to Chris for all the free updates over the years....you don't find that kind of value anywhere anymore.

Maybe Chris could create a board here for off-GW audio topics? It's a pleasure to talk audio with cool people, in a civilized fashion.
Stiiv
DewDude420
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Post by DewDude420 »

dude, it sure is..how many shareware applications that existed 10 years ago still exist.....not too many.


i do remember goldwave being a good value, even back then. i was just starting my exploration in to the audio world and goldwave seemed to be about right at the level i wanted/needed to learn with. i got better, i taught myself. euventually i got pretty good...so good in fact i was starting to feel the bounds of goldwave and branched off into teaching myself adobe audition,

but i still use goldwave, and it's taught me a lot...and as i said...it started this obsession i have with audio. i'm not sure if chris knows how much goldwave changed my life..if an audio program can change someone's like dramatically...i do know this...when i first downloaded it, i said one day doing this stuff was going to get my name in a CD..... Feb. 2006, Bold Chicken came out on smogveil records...and my name was in it....(vinyl trax by jay moore)...complete with the fake company name i came up with......and it was then that i stood back and went "holy crap..i can't believe i did it"

fact is, i paid the old price fo $35 for Goldwave 10 years ago...and i'm still getting updates.....it's been a much better value than any of the other editors have been..since they want you to upgrade every major revision.

case in point: i paid 10x what i did for goldwave for adobe audition a couple years ago for 2.0....3.0 came out..and guess what, again, it's somewhere around $300.

as far as an off-topic forum....provided things don't get out of hand, i don't see a reason for the General forum to serve this purpose....sure, people are going to maybe ask an how-to...but think of it, since we're already here...we'll see it, and that person will get the advice they want much faster, plus there's a better chance more than two or three of us will see it.
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Post by GoldWave Inc. »

It is always great to read such positive posts. I've been very impressed with the level of knowledge, courtesy, and help demonstrated by the members of the GoldWave forums. There is no doubt that the wealth of information here has been helpful to many, many users over the years (including myself).

Chris
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