Microscopes can clearly see the video on the surface of a CED 'LaserDisc,' discovers Techtuber — a 12-inch vinyl-like disc that stores SD analog video

Old video disc formats under a microscope — (Image credit: Tech Tangents )

Tech Tangents (TT) surprised themselves by looking at the surface of a CED ‘LaserDisc’ under a microscope and felt compelled to purchase a new device, with a built-in screen and HDMI out, to share what they had discovered. Spoiler alert: You can clearly see some of the analog imagery stored on a CED surface.

Microscopes can See Video on a LaserDisc - Andonstar AD246S-P - YouTube

Watch On

Like its tape format rivals, the video content stored on a CED was in a standard-definition quality analog form. So, looking extremely closely at the grooved surface can actually give you more than a clue to the content of the disc.

Article continues below

Enjoying the new microscope

After introducing his new microscope and its capabilities, TT finally gets down to some close-up disc scrutiny at around the 14mins mark. Specifically, he zooms in on the surfaces of two samples of actual CEDs. These contain generally better quality (though still analog) video tracks, which were read by a laser pickup. Some of the later LaserDiscs were enhanced with digital PCM audio tracks.

One of the CEDs examined closely was a CAV (Constant Angular Velocity) disc, with its data evidenced by a consistent geometric pattern, whereas a CLV (Constant Linear Velocity) disc under the microscope looks simply colorfully streaky.

“I found an image!”

Now studying the CED surface more earnestly, something caught TT’s eye. “It's not going to happen. We're not going to find an image.” Then, almost immediately, “I found an image.”

The video host explains what we are seeing and that, due to the nature of the CED recording and media, it is possible to see a “meaningful” image on the surface, if and when the video slowly pans across the x or y axis. The first evidence of this phenomenon comes from some video text shown at around 22min 30sec in the video (see image, above).

CED QED

The main event takes place around 25 minutes into the video. A CED disc is (at last) placed under the microscope. After a bit of zooming, focusing, and angling of light sources, TT blurts, “Oh my gosh. We just nailed it. Bang. Right there.”

Again, it is some text, but this time a much clearer representation of the disc content. The CED surface text is almost as clear as a stored video frame on some old film.

After that excitement, the video host moves along to look at a couple of other tech-related artifacts under the microscope. The extras include a surface study of a mixed-mode audio/data CD, and a smartphone screen close-up where the OLED (sub) pixels are clearly visible.

If you reckon the demonstrated desktop digital microscope is a good one, it is the Andonstar AD246S model. We have noticed it is currently 13% off and available for $139 on Amazon.

Follow Tom's Hardware on Google News, or add us as a preferred source, to get our latest news, analysis, & reviews in your feeds.

TOPICS

Mark Tyson is a news editor at Tom's Hardware. He enjoys covering the full breadth of PC tech; from business and semiconductor design to products approaching the edge of reason.

17 Comments Comment from the forums

Skramblr

Title is wrong. That's not a LaserDisc, its a CED ( Capacitance Electronic Disc). These are two different things
Reply
pockyfiend

"Though the media looks quite a lot like a LaserDisc, a CED (Capacitance Electronic Disc) is an unusual video distribution format that existed for a time"

You guys said it correctly in the very first paragraph of the article . So then how did you spend the rest of the article, as well as the headline, getting it completely wrong and calling it a "LaserDisc"?

Are you just getting lazy and writing these with AI these days? 🤦‍♂️

This system actually used a needle, like a vinyl record player, rather than a laser, to read analog audio and analog video, unlike a LaserDisc, which was an optical disc that that used a laser like a CD player to read analog OR digital audio along with analog video (yes, optically-recorded NTSC/PAL analog video signals read by laser.)

I actually had a Capacitance Electronic Disc player ("RCA VideoDisc" / "SelectaVision") was the brand name) with some titles as a kid, including a bunch of Disney discs and Bakshi's The Hobbit. Recently, cleaning out my parents ' basement, I even found some softcore erotica.
Reply
bit_user

Loosely related (about LDs, not CEDs): the first time I saw a CAV laserdisc in person, I knew enough about video that I actually understood the significance of being able to see the line and field structure. That blew me away! If you knew where to look, you could figure out whether the disc had closed captioning information just through visual inspection!

The other thing that blew my mind about Laserdisc is that it's effectively an analog medium! It still works by either the presence or absence of pits, but their spacing in the time domain isn't discrete. This encodes a composite video signal, which is pretty insane, because it means you then need to de-jitter the signal enough that the chroma & luma can be separated. Most video recording formats use a different chroma modulation schema that's much less susceptible to jitter.
Reply
wakuwaku

Skramblr said:
Title is wrong. That's not a LaserDisc, its a CED ( Capacitance Electronic Disc). These are two different things

pockyfiend said:
"Though the media looks quite a lot like a LaserDisc, a CED (Capacitance Electronic Disc) is an unusual video distribution format that existed for a time"

You guys said it correctly in the very first paragraph of the article . So then how did you spend the rest of the article, as well as the headline, getting it completely wrong and calling it a "LaserDisc"?

Are you just getting lazy and writing these with AI these days? 🤦‍♂️

This system actually used a needle, like a vinyl record player, rather than a laser, to read analog audio and analog video, unlike a LaserDisc, which was an optical disc that that used a laser like a CD player to read analog OR digital audio along with analog video (yes, optically-recorded NTSC/PAL analog video signals read by laser.)

I actually had a Capacitance Electronic Disc player ("RCA VideoDisc" / "SelectaVision") was the brand name) with some titles as a kid, including a bunch of Disney discs and Bakshi's The Hobbit. Recently, cleaning out my parents ' basement, I even found some softcore erotica.
You guys didn't subscribe. If you have a subscription, all the false information gets hidden and you are presented with the factually correct non-seo optimized non-LLM mutilated article. How else is Tom gonna persuade free-loaders to pay them money. /S
Btw, CEDs are vinyl, they are not vinyl-like. It is made from vinyl so it is vinyl. The name vinyl comes from the material the disc is made from. Simple and Easy English!
Reply
Kevlarrgh

This intrigues me. The description implies that the signal is read linearly in a spiral path, so how does a coherent FRAME appear optically with successive frame lines on neighboring "tracks"? Is this a pure coincidence where a single track holds all the scan lines +1 in that, or every part of the disc? Also, how does the needle track closely and rapidly enough without touching or marring the disc at video bandwidth?
Reply
bit_user

wakuwaku said:
Btw, CEDs are vinyl, they are not vinyl-like. It is made from vinyl so it is vinyl. The name vinyl comes from the material the disc is made from.
According to Wikipedia:
"The first CED prototype discs were multi-layered, consisting of a vinyl substrate, nickel conductive layer, glow-discharge insulating layer and silicone lubricant top layer. Failure to fully solve the stylus/disc wear and manufacturing complexity forced RCA to seek simpler construction of the disc. The final disc was crafted using PVC blended with carbon to make the disc conductive. To preserve stylus and groove life, a thin layer (up to 50 nm thick) of silicone (polysiloxane) or methyl alkyl siloxane was applied to the disc as a lubricant."
So, I think it's not accurate either to say it's vinyl or entirely vinyl-like. Perhaps you could describe "PVC blended with carbon" as "vinyl-like", but that overlooks the coating.

wakuwaku said:
Simple and Easy English!
"Everything should be made as simple as possible, but not simpler."
-- Albert Einstein
Reply
bit_user

Kevlarrgh said:
This intrigues me. The description implies that the signal is read linearly in a spiral path,
Yes, like a conventional record.

Kevlarrgh said:
so how does a coherent FRAME appear optically with successive frame lines on neighboring "tracks"?
That happens when you have some scrolling text. If scrolling at an appropriate speed, the same scanline, over successive frames, shows progressively more of the text. Put together, you see a scan-out of the full text. At least, that's how I understood it.

That's why the sample images are showing credits. It would also work when the camera pans down.

I think the same thing would probably work with CAV laser discs.

Kevlarrgh said:
Also, how does the needle track closely and rapidly enough without touching or marring the disc at video bandwidth?
My understanding is that it does touch the disk, but that the groove is merely serving the purpose of guiding the head. Unlike in audio records, head detects the depth of the groove through variation in capacitance (i.e. the deeper the groove, the lower the capacitance). Because there's not a needle that's vibrating at video frequencies (i.e. several MHz), you don't have mechanical wear-out of the signal portion.
Reply
80251

A really interesting read. Now do an article on DAC!
Reply
twincitynights

The term 'Laserdisc' needs to be fully scrubbed from this article. CED discs are played with a needle (physical contact) and are completely different than Laserdiscs, which are optical and read with a laser.
Reply
DVDfever2

Tom's Hardware can't understand what a CED is when it sees one. "Hardware" expert?! What a joke!
Reply

Show more comments