CDs, DVDs, and Blu Ray

Podcast Transcript

In 1982, the Phillips and Sony Corporations jointly released the compact audio disc to the world.

The technology involved was originally just used to play digital audio, but it actually had much more potential.

Over the last 40 years, basic optical disc technology used in CDs has expanded to store digital video and every type of digital data.

Yet, despite the ubiquity of the internet and the ability to access digital files all over the world, there is still a demand for this technology.

Learn more about optical discs, CDs, DVDs, and Blu-Ray discs on this episode of Everything Everywhere Daily.

I have to confess despite the access we have to streaming movies and music, I have a soft spot for physical media.

I personally have an extensive film collection that I started over twenty years ago. I’ve upgraded and expanded it over the years, and it now includes a little under 1,000 films.

In a previous episode, I covered the history of digital audio and how it works. In this episode, I want to focus on optical disc technology, how it has expanded beyond music, and how it is still used today.

The story actually begins with the invention of the laser, which I covered in a previous episode.

After years of work throughout the 1950s, the first working laser was developed in 1960 at Hughes Laboratories in a research group led by Theodore Maiman.

Laser, an acronym for Light Amplification by Stimulated Emission of Radiation, was a revolutionary invention. Lasers allow for an extremely focused, narrow beam of light where all photons are aligned.

At the time, researchers weren’t even aware of what they could do with this revolutionary new tool.

One person who thought about its practical applications was James Russell.

In 1965, he conceptualized and patented an idea for a digital optical storage system that encoded information in microscopic pits on a disc and used a laser beam to read the data without physical contact.

He received two patents for his ideas in 1966 and 1969 and had a prototype working by 1973. He pitched his idea to over 100 companies, and it was reported in scientific magazines as early as 1972. Two of the companies he presented to were Sony and Phillips.

In 1978, Phillips, along with MCA and Pioneer, commercially released the laserdisc.

The laserdisc was an optical storage format, but it wasn’t digital.

The laserdisc was larger than a CD at a full 30 cm or 12 inches in diameter. It looked like a CD the size of a vinyl album.

The pits and lands on the LaserDisc surface encode analog video and audio.

Video is stored as an FM or frequency-modulated analog signal, similar to the way video signals are transmitted in television broadcasting.

A red laser beam shines on the surface of a laserdisc as it spins.

The laser reflects off the pits and lands, converting the reflected light into an electronic signal.

This signal is processed and sent to a television for video playback and speakers for audio playback.

LaserDisc offered superior video and audio quality compared to VHS tapes because it did not degrade with repeated use.

It also supported additional features like chapter selection, freeze frames, and slow-motion playback.

Despite being a superior technology to VHS, the cost of players and discs ensured that it remained a niche market. Today, there is still a small, enthusiastic group of Laserdisc users.

However, the holy grail was to create a digital optical storage system, not an analog one.

After Laserdisc struggled, Phillips began working on digital storage. In 1979, they partnered with Sony who had been working on their own system.

Phillips brought to the table their knowledge of optical storage, which they developed via the creation of Laserdisc, and Sony contributed its know-how in digital audio processing.

The partnership led to the creation of the Red Book standard in 1980, which defined the technical specifications for Compact Digital Audio Discs.

The format specified that the disc be120mm in diameter and have a capacity of 74 minutes of audio. According to legend, this was based on the wife of the Sony CEO, who wanted to have a complete recording of Beethoven’s Ninth Symphony on one disc.

The audio was to have a Sampling rate of 44.1 kHz with a Bit depth of 16-bit audio.

A low-power laser beam was used to read the data encoded as microscopic pits and lands on the disc.

Advanced coding methods ensured data integrity even if the disc was scratched or dirty.

A standard CD has four layers: A polycarbonate layer, which is the base of the CD, is made of clear plastic. This layer provides structural support and contains the microscopic grooves.

A reflective layer, which is a thin aluminum or gold layer lies above the polycarbonate. It reflects the laser beam used to read the disc.

A protective layer, which is a lacquer coating that protects the reflective layer from scratches and damage.

And finally, the label layer. The topmost layer where information about the CD is printed.

The first commercial CD was released on October 1, 1982, in Japan.

The first album released on audio CD was “52nd Street” by Billy Joel.

Philips released the first CD player, the CDP-101, in 1982, which was initially expensive and aimed at audiophiles.

CD eventually took over vinyl sales by 1988 and became the dominant form of music.

However, audio was just the beginning. If audio could be digitally encoded, then anything digital could.

In 1983, Phillips and Sony released the Yellow Book standard, which set forth the standards for compact disc read-only memory, or CD-ROM.

CD-ROMs were quite popular for a while as they stored much more data than floppy discs. CD-ROMs became the standard for software distribution in the 90s.

However, there was more that could be done.

In 1990, the Orange Book was released, which set the standard for both CD-R and CD-RW.

CD-R was also known as CD write once. You could write something to the disk and then it was there permanently.

CD-RW was also called CD read/write. It was a disc that could repeatedly be written and read, just like a regular floppy disc.

Instead of a permanent metallic reflective layer, a CD-R had a dye layer. The laser in the CD writer heats the dye layer, creating permanent marks that mimic the pits of a normal CD.

CD read/write discs contain a special phase-change material in place of the dye layer. When exposed to different laser intensities, the material can switch between crystalline and reflective, as well as amorphous and non-reflective states.

A standard read/write CD would be writing about 1000 times.

In order to grow the market, it was necessary to increase the capacity of discs. I remember versions of Microsoft Windows that came on multiple CD’s.

Moreover, the video business was a huge potential market that could be replaced, just like CDs replaced vinyl.

This led to the development of the Digital Versatile Disc or DVD….and yes, the V in DVD actually stands for versatile, not video.

DVDs were developed as a collaboration among major technology companies, including Toshiba, Sony, Panasonic, and Philips. The goal was to create a format for high-capacity storage suitable for video and data.

The DVD was officially introduced in 1995 and released to the market in 1996.

Movies had been released on CD in a format known as CD Video, but the discs were big enough to contain an entire full-length movie.

DVDs could store significantly more data than CDs. They could hold 4.7 GB on a single-layer disc versus 700 MB for a CD. Furthermore, a DVD could have different layers and be double-sided, increasing the total capacity to 17 GB.

This was done by creating smaller pits on the surface and reading them with a shorter-wavelength laser. DVD uses a red laser with a shorter 650 nm wavelength instead of a CD laser, which is infrared with a 780 nm wavelength.

DVDs introduced features like menus, chapters, and bonus content, which became a hallmark of home entertainment.

The first movies released on DVD in Japan on December 20, 1996, were The Assassin, Blade Runner, Eraser, and The Fugitive.

It took a few years, but DVDs finally started to hit their stride in the early 2000s when the cost of DVD players came down.

However, soon after DVDs started to become popular, the shift to high-definition video began.

High-definition videos took up considerably more data.

A frame of standard definition video is 720×480 pixels or 345,600 total pixels.

A frame of high-definition 1080p video is 1920×1080 pixels, or 2,073,600.

To put it more succinctly, a frame of high-definition video has six times more data.

You need smaller pits and a laser with an even shorter wavelength to store that much more data.

From 2000 to 2006, Blu-ray discs were developed by the Blu-ray Disc Association, which included Sony, Panasonic, Philips, and others.

The name refers to the blue-violet laser used to read and write data, which has a shorter wavelength than the red laser used in DVDs, allowing for higher precision and capacity. A blu ray laser has a wavelength of 405 nanometers.

Single-layer Blu-ray discs store 25 GB, and dual-layer discs store 50 GB.

The first Blu-ray discs were released to the market in 2006.

The Blu-ray format was launched in competition with a competing format known as HD DVD, a format developed by Toshiba.

However, by 2008, Blu-ray won the format war, becoming the standard for high-definition video.

The high-definition video was pretty good, but even that was improved with the deployment of 4 K ultra-high-definition video.

4K video has a resolution of 3,840 x 2,160 pixels, giving it a picture with four times more resolution than high-definition video.

A 4k UHD disc uses the same type of Blu-ray laser. The difference primarily has to do with the video encoding.

The Blu-ray Disc Association released the standards for 4K Blu-ray in 2015 at the Consumer Electronics Show.

A 4k Blu-ray disc can hold up to 100 GB of data, and the video formats support high-dynamic-range video and advanced audio, such as Dolby Atmos.

4k Blu-ray hasn’t had the wide spread adoption of other optical disc formats. There are a few reasons for this.

First, you have to have both a 4k Blu-ray player and a 4K television set to play a disc.

Second, is that while the jump from standard definition DVD to blu ray was dramatic, the difference between blu-ray and 4K is much smaller to the naked eye.

Finally, streaming services have mostly eliminated the demand for physical media.

Despite that, there is still a small and loyal group of enthusiasts such as myself who still buy blu-ray and 4K movies.

There are good reasons for this. For starters, most movies, the vast majority of which are not available on streaming services. The ones that are available are often only available for a limited amount of time before being removed.

The other reason is quality. Even if a video on, say, Netflix says it is in 4k, the bit rate is much lower, and the compression on the video is much higher.

A 4k streaming video doesn’t look bad, but there is a marked obvious difference between watching it on disc.

I’ll end this episode with something that many of you might have noticed if you have gone into an electronics store recently. They are now selling 8K televisions, which have an even higher resolution picture than 4K.

Does that mean that we are going to have 8k discs on the market soon?

The answer to that is, almost certainly, no.

For almost any television that could fit into a residential home, there will be no discernable difference in video quality between 4K and 8K. Our eyes simply can’t distinguish the difference.

That is why there is zero demand for 8K discs at the moment, and there probably never will be. Given the drop in demand for physical media due to streaming, manufacturers especially don’t see the point in investing in a brand-new format that few people can even watch.

Physical media for both music and video is not what it used to be. The internet has largely supplanted physical media for most people.

That being said, physical optical media still has its place in the 21st century.