Slashdot Mirror
The History of the CD-ROM
Gammu writes "The inventor of the compact disc, the most popular medium in the world for playing back and storing music, is often disputed as one individual did not invent every part of the compact disc. The most attributed inventor is James Russell, who in 1965 was inspired with a revolutionary idea as he sketched on paper a more ideal music recording system to replace vinyl records; Russell envisioned a system which could record and replay sounds without any physical contact between parts."
4-8GB of mp3 space vs 800MB for a CD-R.
They just don't make it like they used to!! I was given a Discman D-50 (hand-me-down) around 1987 and it is still running GREAT today. Fact is I never had a need to upgrade. The newer units were made out of plastic (d-50 is METAL) and tended to have lower quality D->A as well as inferior processing. It is still hooked up to my stereo as I never used it as a "portable."
Chalk one up for Sony's quality during it's power years of the 1980s. I plan to keep using it for many more years!
I wouldn't be surprised to see a graph with the CD-R market booming, and the mini-disc market failing.
Your wish is my command
If I could go buy say that Star Wars soundtrack on DVD-Audio tomorrow, I would. But I don't believe I can. If I had to guess nobody wanted to go through 25 years of CDs and remix them to 5.1 channel surround sound. Can't say I blame them, but it pretty much killed the format.
Nope, not Tchaikovsky. The CD was enlarged from 11.5 to 12 cm to be able to fit 74 min of music, the longest known recording of Beethoven's nineth symphony.
OK, a look at the Wikipedia answers my question. Looking at the NTSC article, it states "Each frame consists of 486 lines out of a total of 525 (the rest are used for sync, vertical retrace, and other data such as captioning)" (Divide the number by 2 because of interlacing). The corresponding PAL article states that PAL is "a video format that has 625 lines per frame (576 visible lines, the rest being used for other information such as sync data and captioning)". OK, so they could use a few, but not many, lines in the "vertical sync" to store more PCM audio. And that is exactly what they did.
So why 44.1 instead of 44.056? PAL-based PCM systems had a 44.1 sampling rate; NTSC systems 44.056. They chose 44.1 because it was an easier to remember number.
So there you have it. More than you ever wanted to know about why CDs have a 44.1 sampling rate.
And, oh, I like CDs more than MP3s. Thank you, I care about audio quality, and hate the sound of 128k mp3s. Especially the crappily encoded ones that sound really metallic.
Link
But, I hope you're correct.
You are being MICROattacked, from various angles, in a SOFT manner.
However, Sony vice-president Norio Ohga, who was responsible for the project, did not agree. "Let us take the music as the basis," he said. He hadn't studied at the Conservatory in Berlin for nothing. Ohga had fond memories of Beethoven's Ninth Symphony ('Alle Menschen werden Brüder'). That had to fit on the CD. There was room for those few extra minutes, the Philips engineers agreed. The performance by the Berlin Philharmonic, conducted by Herbert von Karajan, lasted for 66 minutes. Just to be quite sure, a check was made with Philips' subsidiary, PolyGram, to ascertain what other recordings there were. The longest known performance lasted 74 minutes. This was a mono recording made during the Bayreuther Festspiele in 1951 and conducted by Wilhelm Furtwängler. This therefore became the playing time of a CD. A diameter of 12 centimeters was required for this playing time.
In this way the specifications of the CD were determined by means of intensive contact between Philips and Sony.
http://www.research.philips.com/newscenter/dossier /optrec/beethoven.html
Just thought you'ld like to know
qz
Just to pick at a nit here, Gregg's work was an analog recording, not digital. If you look at the direct derivitive of Gregg's work - the LaserDisc - you'll find that the data is encoded in a Pulse Width Modulation format. This allowed for NTSC signals to be directly recorded to discs long before the invention of digital encoding technologies like MPEG.
In fact, the microprocessor technology necessary to decode a digital datastream into television quality video cost millions of dollars back when the LaserDisc was introduced to the market. During development of the format, the necessary framebuffer devices were still in development and wouldn't reach truecolor capabilties until the New York Institute of Technology experiment in 1977. (They took three 8-bit, grayscale framebuffers manufactured by Evans & Sutherland and wired them together to create a 24-bit display.)
So as you can imagine, an analog design was far superior to a digital video format back when Laserdiscs were introduced.
Javascript + Nintendo DSi = DSiCade
If I recall correctly it was Ron Kok, a Dutch entrepreneur, who came up with a *MUCH* more efficient production method to make them cheaper. He put the separate components inline and improved the sequence, thus taking away a lot of the media handling which caused quality issues. Quality went up, volume went up, price came down.
Did the guy get rich off it? No, because in those days he was naive and thus had it stolen and copied from right underneath his nose. He's fared better since, but he's the guy that's responsible for CDs being so dirt cheap (AFAIK, been a while since I heard this).
Insert
As many audiophiles will tell you, though humans cannot generally perceive tones above 20kHz, they are able to use high-frequency information for things like localization, and an entire high-resolution sound recording market, based on 96 and 192 kHz recording formats is built around it. The quote from the website above sort of tries to reason the 44.1 issue backwards: why didn't they just do 44.0 or (44.2 even?) if they were trying to find a sample rate that didn't convert so well? Particularly when the best analogue formats, like 30 ips 2 inch tape, can record up to 30 kHz?
Here's the story my recording engineering teachers passed down to me, accept it if you wish:
A long time ago the only way you could make a digital recording (without building a cleanroom or spending $10 grand on a 1 Gig hard drive) was to take your digital bit-stream and record it on some kind of helical video tape. Sony was the first company to sell these devices, which were basically black boxes with audio in on one side, and video out on the other; you would then take this video signal (which looks like "checkerboard" noise on a TV) and send it to a VCR to record. The best commonly-available video recording format at the time was 3/4" U-Matic.
U-Matic can record the full 525 lines of an NTSC image at (nominally) 30 frames/sec. In tests, the Sony engineers found they could squeeze about 47,040 bits into a frame. (There's some way this worked out into an integer number of bits per an integer number of lines, but I can't remember the math right now. It averages about 90 bits per line.)
So, if you have 47,040 bits per frame, you have 1,411,200 bits per second, which is 176,400 bytes/sec, which is the data rate of 44.1 kHz stereo PCM. The system also works for PAL, which only runs at 25 video frames per second, but has 625 line to record on, making up the difference.
Don't blame me, I voted for Baltar.
CD was not the first technology to read discs without physical contact. RCA had a turntable capable of "reading" vinyl records with a light-beam in the late 1930s.
s g_0000018187.shtml
The RCA Magic Brain Victrola/Radio "was advertised as being able to play both sides of a record without turning it over and used a jewel-lite scanner that eliminated the needle and you could stack up to 15 records at a time."
Sometimes seen advertised on RCA 78rpm record labels of the period.
http://www.phonoland.com/archives/mboards/18100/m
"You must try to forget all you have learned. You must begin to dream." -- Sherwood Anderson
IIRC, he also released the first OS on CD-ROM as well. Apple's OS was STILL on floppies up until what, 1996-97?
Absolutely not. Apple included the IIvx software on CD-ROM (and floppy - System 7.0.1 with IIvx enabler) in 1994. Later that year, the Quadra 630/650 System Software (again, 7.0.1 or 7.1 with an enabler) shipped on CD. Next up was System 7.1.1., shipped with the PowerSurge machines (first PCI power Macs - the 9500/7500) shipped on CD-ROM.
Apple was ahead in CD-ROM distribution; when I started work there in 1994, many calls were from IIvx and Quadra 630/650 owners asking for replacement CDs.
Nonsense. The article is right.
All AC-3 laserdiscs were at 320kbit/s. In theory, they shouldn't even sound as good as DVD, let alone better.
In practice, the reason laserdisc AC-3 sounds "better" is because LD was too much of a niche market for the studios to do anything other than take the theatrical mix, peform the 3dB volume reduction on the rear channels (theatrical mixes are boosted by that due to assorted amp stuff that clearly made sense to someone when they designed it, but I'm blowed if I'll every figure it out) and then slap it on the disc.
For DVDs, however, they do clever things to make the mix more suitable for home listening. Because 5.1 tracks are folded down to stereo in the player for people without surround systems, it's a game of compromises to make the 5.1, 5.0 (not everyone has a sub) and 2.0 folded versions all sound acceptable. Also, the insane quantities of bass used in theatrical mixes these days would overwhelm cheap systems, so they try not to cook it too hard.
The DVD of Jurassic Park (after a load of complaints about the initial release) is a straight port of the laserdisc audio in the Dolby release for example, and sure enough sounds like it.
"I Know You Are But What Am I?"
Look up the concept of a difference tone. Per Norgard creates some weird sonorities in his Symphony No. 5 by having a dog whistle blown at the same time as a tone is produced by one of the traditional orchestral instruments. The sound on its own would be beyond human ears, but the combination of the two sounds is audible. Norgard's not the only one who writes stuff like that, there's a whole wealth of repertoire that takes advantage of the phenomenon. If you listen to a low bitrate lossy file that has the high ends thrown out, you miss the mix of sounds as it was when the music was performed and recorded, making it sound flat.
iTunes is way, way too difficult to mess with
What? You fill out your name and address, plug in a credit card number, pick a password.
When you're ready to buy you click on one button and re-enter your password. You can even check a box so you never have to re-enter your password, and reduce that step.
How's that hard?
Why do I M2 everything negatively?
The word "Blue Ray" is too generic to be trademarked (and you can't trademark "Blue"), so they went with "Blu" because that can be.
"Slashdot - News and Chat Sites Deviant". (Click "homepage" link above for details).
I worked on the Philips team who first put computer data onto a CD - so my group were the first with the CD-ROM. At Philips Research labs in Redhill, Surrey, UK we took a modified Philips consumer CD player (before they were on sale to the general public though) and hooked it up to an experimental home computer we were working with (a 68000-based machine called C.H.R.I.S). The very first CD-ROM contained a demonstration of an interactive dictionary - with pictures, audio pronunciation, hyperlinks, etc. However typing in all of those words - having our team's secretary read it all out (she had a really nice voice!) and paying an artist to use my experimental paint program to make all the pictures...all turned out to be *WAY* too much work - and whilst the CD-ROM had 720Mbytes capacity, the hard drives of that era were 20Mbytes - so assembling all the data was going to be really tough. We ended up doing just the letter 'O' (why 'O'? I don't recall.)
My job entailed writing a paint program for CHRIS so we could prepare the pictures. The only digital paint software of that era was the Quantel paintbox - and it cost a lot of money - so we did it ourselves.
We did quite a few ground-breaking things - the machine had a touch-screen (mice hadn't been invented in those days!), a 256 colour display, antialiased proportional-space fonts (pretty revolutionary for the time), hyperlinks, an on-screen 'soft' keyboard and a small hard drive.
The digital data had to be transferred to a DEC VAX computer, written to 9-track mag tape and send to Holland to be pressed onto disks. There was a long lead time - and we weren't exactly a high priority for the pressing plant - so it was a struggle to get them done.
We pressed about 50 CD-ROM dictionary disks - and eventually did a second run of about the same number to fix up some problems. As far as a know, nobody realised the importance of this - and not one single one of those original disks has survived.
Steve Baker.