HDCD. Anyone heard this?
Kent Smith
"GraB" <gr...@nothing.co.nz> wrote in message
news:h8og50hb3p0gpvb8u...@4ax.com...
> http://www.hdcd.com/about/index.html
>
> Noticed the HDCD (High Definition Compatible Digital) logo on a DVD
> player I was looking at in Dick Smiths but the assistant didn't know
> what it was, so I looked it up . . . and found it is yet another
> startup technology acquired by Microshaft.
>
> But what does it sound like? Anyone heard it? Does it threaten DVD
> Audio or SACD? (A quick look online seems to indicate that it
> doesn't).
From memory, I believe...
CD is 44,000 samples per second at 16 bits.
HDCD is 44,000 samples per second at 20 bits.
DVD-Video sound is 6 channels of 48,000 samples per second at 24 bits.
DVD-Audio is 6 channels of 96,000 samples per second at 24 bits (but can do
2 channels at 192,000 and I've heard 384,000 (maybe one channel?) too) -
lossless compression
SACD is 6 channels 192,000 samples per second at 24 bits - lossy compression
Open to corrections. There are other hybrids and configurations, but these
are the most common.
-KENT
Stuart Richards
>
> From memory, I believe...
>
> CD is 44,000 samples per second at 16 bits.
44,100, not 44,000.
> HDCD is 44,000 samples per second at 20 bits.
Nope, still 16 bits, just with playback decoding necessary for full quality.
> DVD-Video sound is 6 channels of 48,000 samples per second at 24 bits.
Up to 8 channels of PCM (but good luck finding a player that can output all 8)
Up to 96,000 samples per second per channel
Audio bitrate is limited to 6.144 Mbps (which restricts things somewhat)
> DVD-Audio is 6 channels of 96,000 samples per second at 24 bits (but can do
> 2 channels at 192,000 and I've heard 384,000 (maybe one channel?) too) -
> lossless compression
DVD-Audio can't do 384,000 samples per second, 192,000 is the maximum.
> SACD is 6 channels 192,000 samples per second at 24 bits - lossy compression
SACD is up to 6 channels and uses *lossless* compression (called DST, for
Direct Stream Transfer).
SACD uses a single bit sigma-delta (sometimes called delta-sigma, it depends
on who you ask) encoding scheme which is sampled at 2.8224 MHz (exactly 64
times the sample rate of CDs, which is not a coincidence) called DSD. It is
nothing remotely like PCM.
An inherent limitation with the DSD encoding used on SACD is that the
signal-to-noise ratio reduces with increasing frequency (i.e. it gets noisier
the higher up you go), unlike PCM where the SNR is the same at all
frequencies.
I don't think SACD is anywhere near as good as it's hyped up to be. Sony
likes to present it as being "cutting edge" and "state-of-the-art", which
would've been true, had it actually come out in the early 90s when the whole
1-bit "bitstream" thing was new. Seeing as it came out in 1999 i'd say they
missed the boat, technically speaking. SACD is actually rather dated when you
look at it closely.
newsreader
"Stuart Richards" <st...@xtra.co.nz> wrote in message
news:4058EB5C...@xtra.co.nz...
>
> DVD-Audio can't do 384,000 samples per second, 192,000 is the maximum.
>
Correct.
384kbps is a number best associated with Dolby Digital encoding for 5.1
channel film soundtracks. This was the common bitrate for Dolby Digital
laserdiscs and early DVD-Video discs.
384kbps is also the maximum data rate for MPEG-1 audio.
Most Dolby Digital 5.1 DVDs now use 448kbps.
SGN Craig
> >
> > From memory, I believe...
> >
> > CD is 44,000 samples per second at 16 bits.
>
> 44,100, not 44,000.
>
> > HDCD is 44,000 samples per second at 20 bits.
>
> Nope, still 16 bits, just with playback decoding necessary for full quality.
>
---snip---
Could you explain this? I thought HDCD was 20 bits? And what do you
mean by "playback decoding necessary for full quality"?
Thanks.. Very informative post!
Stuart Richards
>
> "Stuart Richards" <st...@xtra.co.nz> wrote in message
> news:4058EB5C...@xtra.co.nz...
> >
> > DVD-Audio can't do 384,000 samples per second, 192,000 is the maximum.
>
> Correct.
>
> 384kbps is a number best associated with Dolby Digital encoding for 5.1
> channel film soundtracks. This was the common bitrate for Dolby Digital
> laserdiscs and early DVD-Video discs.
Yes, but by "384,000 samples per second" I meant 384 kHz, which at 24 bits per
sample would be 9,216 kbps and that's only for one channel!
BTW, that 384 kHz @ 24 bits per channel format *is* actually supported by at
least one DAW out there. You just can't get that in any post-CD consumer
audio format yet (i.e. SACD and DVD-Audio).
Stuart Richards
>
> Stuart Richards <st...@xtra.co.nz> wrote in message
> news:<4058EB5C...@xtra.co.nz>...
> >
> > Kent Smith wrote:
> > >
> > > From memory, I believe...
> > >
> > > CD is 44,000 samples per second at 16 bits.
> >
> > 44,100, not 44,000.
> >
> > > HDCD is 44,000 samples per second at 20 bits.
> >
> > Nope, still 16 bits, just with playback decoding necessary for full
> > quality.
>
> mean by "playback decoding necessary for full quality"?
CD is only 2 channels worth of 16 bits @ 44.1 kHz (1,411.2 kbps in other
words), so no trick that HDCD could pull would get it more than that, short of
actual data compression, which it doesn't do.
If HDCD *did* use data compression, then it would be totally incompatible with
CD, i.e. if you played an HDCD in an ordinary CD player it would sound like
white noise. Interestingly, MLP (Meridian Lossless Packing), a form of
lossless data compression used on DVD-Audio, was actually demonstrated in this
way, but no MLP compressed CDs are for sale.
HDCD encoding is like a combination of both Dolby B noise reduction and HX Pro
on cassettes, in a sense. The "dynamic decimation" feature of HDCD is
something any CD player can benefit from, since it doesn't need any decoding
(like how Dolby HX Pro encoded cassettes are playable in full quality on
non-HX Pro cassette decks).
The "peak extension" and "low level extension" features of HDCD both require
decoding, but if your CD player can't decode them, i.e. if it isn't an HDCD
player, then the resulting sound is still acceptable to most people (like how
Dolby B encoded cassettes are only playable in full quality on Dolby B
cassette decks, but still sound okay even when you play them in non-Dolby B
cassette decks).
To sum up, HDCDs sound best when played on HDCD players, because they are
encoded in a way that requires decoding for best results, something only HDCD
players can do.
For more info go here: http://www.hdcd.com/partners/proaudio/hdcdmix.html
El Penguino
wrote:
>
>BTW, that 384 kHz @ 24 bits per channel format *is* actually supported by at
>least one DAW out there. You just can't get that in any post-CD consumer
>audio format yet (i.e. SACD and DVD-Audio).
That doesn't compute . 384K x 24 bits x 6 ( channels ) x 60 ( seconds
in a minute ) x 90 ( mins in a movie ) is almost 200 GB .
384 k is the speed of a whole AC3 bitstream , using lossy compression.
.
Stuart Richards
>
> On Fri, 19 Mar 2004 14:12:07 +1300, Stuart Richards <st...@xtra.co.nz>
> wrote:
> >
> >BTW, that 384 kHz @ 24 bits per channel format *is* actually supported by
> >at least one DAW out there. You just can't get that in any post-CD
> >consumer audio format yet (i.e. SACD and DVD-Audio).
>
> That doesn't compute . 384K x 24 bits x 6 ( channels ) x 60 ( seconds
> in a minute ) x 90 ( mins in a movie ) is almost 200 GB .
Your calculation is very wrong.
384,000 samples per second * 24 bits per sample * 60 seconds in a minute =
552,960,000 bits per minute per channel
552,960,000 bits per minute per channel * 90 minutes = 49,766,400,000 bits
49,766,400,000 bits * 6 channels = 298,598,400,000 bits total
298,598,400,000 bits total / 8 bits in a byte / 1,073,741,824 bytes in a
gigabyte = 34.761 gigabytes approximately.
> 384 k is the speed of a whole AC3 bitstream , using lossy compression.
Since when was I talking about 384 kHz having anything to do with Dolby
Digital? I didn't even mention Dolby Digital. I was talking about an audio
format supported by at least one DAW (Digital Audio Workstation), not a
consumer audio format and nothing to do with any sort of data compression,
lossless or lossy.
El Penguino
wrote:
<snip>
>
>552,960,000 bits per minute per channel * 90 minutes = 49,766,400,000 bits
>
>49,766,400,000 bits * 6 channels = 298,598,400,000 bits total
>
>298,598,400,000 bits total / 8 bits in a byte / 1,073,741,824 bytes in a
>gigabyte = 34.761 gigabytes approximately.
Well spotted , give yourself a pat on the back . Its still too much to
fit on a a DVD .. Of course it may all be encoded to mp3 in your DAW .
>> 384 k is the speed of a whole AC3 bitstream , using lossy compression.
>
>Since when was I talking about 384 kHz having anything to do with Dolby
>Digital? I didn't even mention Dolby Digital.
You mentioned it here
_________
"Stuart Richards" <st...@xtra.co.nz> wrote in message
news:4058EB5C...@xtra.co.nz...
>
> DVD-Audio can't do 384,000 samples per second, 192,000 is the maximum.
>
Correct.
384kbps is a number best associated with Dolby Digital encoding for
5.1
channel film soundtracks. This was the common bitrate for Dolby
Digital
laserdiscs and early DVD-Video discs.
384kbps is also the maximum data rate for MPEG-1 audio.
Most Dolby Digital 5.1 DVDs now use 448kbps.
________________
I was talking about an audio
>format supported by at least one DAW (Digital Audio Workstation), not a
>consumer audio format and nothing to do with any sort of data compression,
>lossless or lossy.
newreader also mentioned it .
Calm down fella - it's just a newsgroup .
Stuart Richards
>
> On Sat, 20 Mar 2004 00:19:07 +1300, Stuart Richards <st...@xtra.co.nz>
> wrote:
> >
> >Since when was I talking about 384 kHz having anything to do with Dolby
> >Digital? I didn't even mention Dolby Digital.
>
> You mentioned it here
>
> news:4058EB5C...@xtra.co.nz...
> >
> > DVD-Audio can't do 384,000 samples per second, 192,000 is the maximum.
As you can see, I mentioned DVD-Audio, not Dolby Digital.
As for the following...
> Correct.
>
> 384kbps is a number best associated with Dolby Digital encoding for 5.1
> channel film soundtracks. This was the common bitrate for Dolby Digital
> laserdiscs and early DVD-Video discs.
>
> 384kbps is also the maximum data rate for MPEG-1 audio.
>
> Most Dolby Digital 5.1 DVDs now use 448kbps.
Get your attribution right. I did not write the above, newsreader did.