CED Performance-is it Supposed to Be This Bad?

[wa2ise]

Originally Posted by andy

It's surprising, but CED came out after Laserdisk, Beta, and VHS. It's true that development started in the 60's, but they didn't have a commercial product until about 1981. I've heard CED blamed for putting RCA out of business. They spent color TV kind of money on a product that was obsolete before it was released.

RCA dropped about $570 million on this thing. It is possible that some shareholders asked GE and others to take RCA over, so as to get rid if the fools in the boardroom who thought CED would fly.

Oh, I suppose, if RCA was able to hit the streets with this thing back around say 1972 or so, then it would have been a hit. But the critical technology, like how to make the needle, and how to cut the grooves in the disk, obviously wasn't ready then.

The CED system used an FM modulation scheme like that used in videotape to encode the video into the modulation of the grooves. Biggest annoying problem was that any impurities in or on the disc would make for skipping. The machine had a scheme to advance the needle to take care of backwards skips, but no similar scheme to move the needle back after a forward skip, to maintain the cadence of the movie being played. I knew the guys who developed this firmware, and they said that they planned to do this, but the big bosses froze everything so they could ship product. This was at the old RCA Lab in Princeton NJ.

When it didn't skip, CED did make a somewhat better video image than VHS tape (3Mhz vs 2Mhz).


In a sense, DVD disks are equivalent to CED discs, in that (back in DVD's early days) neither was recordable. You had to buy prerecorded movies. So why did DVD succeed in the marketplace, and CED bomb? The fact that DVD worked well would be a secondary consideration here.

I remember hearing that various RCA dealers electronics stores were unhappy about having to devote salesfloor space to CED. One said "I want to kiss this thing a quick goodbye!".

[truetone36]

I have 2 machines and about 40 or so discs. The performance of this format is FAR from impressive.

[Red October]

I've got the skinny on these things.
You cannot expect a good picture. In theory it is capable of a picture as good as plain-Jane Betamax -that is, better than VHS, but not jaw-droppingly so. In spite of the enormous sleeve, the system is still prone to problems from dust & contaminants. Playing the disc a few times cleans them off; truly bad places can be treated by leaving the player in "Page mode" on the trouble spot-that is, a 4-frame repeat- of the affected area. You can do this on most players by holding down both visual search keys at once, assuming it has no obvious "Page" key. If a minute of this doesn't clear up the defect, then it is knackered and nothing can be done.

The format's capabilities were untapped. The top-of-the-range players were fully interactive, just like DVD players, and could play games, teach lessons, etc. Very few discs were released for these players and the system languished as a crappy home video format before dying. Its other advantage was price, but by the time it came out it couldn't beat an entry-level Sanyo Betamax, and while the picture was no better, the Beta could record and didn't require a gantry crane to move its media. The story goes, that if the system had come out when it was supposed to, in the early/middle seventies, it would have been the dominant home-video playback format. One thing coppied from it is the fact that on some DVDs, the menu is in the "middle", minimizing seek time to a given point from the menu.

On a whole, the system is impressive not because it makes amazing video or audio, or even its interactive capabilities (LD had this much better as it could lock to a frame, so even a CAV LD doubles capacity on the CED since must repeat every frame four times for a still picture.), but because it worked at all, and got as far as it did. It was produced entirely in the United States and could be seen as a last hurrah for RCA before American electronics rolled over and died.

[Celt]

I had a stereo RCA way back then. As I recall, the picture was no better nor worse than VHS of the era. But the audio was quite excellent. Mistracking was a problem though. The grooves are tiny and the disc spins at an insane speed.

[Eric H]

Hard to believe it's been nearly 30 years since I first saw this format, I just recall it had "artifacts" in the picture that were disturbing, especially for something that was supposed to be the next big thing.

Oh well, I was sadly disappointed with my first VHS recorder in 1983 too.
DVD on the other hand was pretty superb right off the bat, sure some of the early players had some problems playing some discs but nothing major and they came down in price fairly quickly.

I can't recall the last time I had a DVD that wouldn't play.

[AnalogDigit]

Originally Posted by leadlike

Analogdigit, that's funny about the sound-I remember that is all my dad liked about that format. He was convinced the sound quality was much better than VHS.

The player that my brother had made a static-type noise through the TV speakers using the RF output. To me, it sounded like listening to a old time radio program. We even tried using the RCA audio out and it produced the same sound.

[leadlike]

Analogdigit, if your brother's player was a Sears model, I concur-they are terrible players. I picked up one of these at a Value Village and it needed a ton of work to get going. Once it did, the sound and picture were terrible. These were rebadged Hitachis, which require a very special needle that was tough to find even then. The J/K series RCAs are very dependable, the only part that goes bad being the tiny belt that drives the loading system.

These discs are a bit more resiliant than one would think-I had a copy of Rust Never Sleeps for years, and who knows how many times I pulled it out of the caddy and got my grubby hands on it. I even put it on my turntable to see if it would play! After all that, it doesn't skip any more than any of the other titles I have had.

It should be noted that you should always inspect your discs before playing them. I've found some that were covered in tiny handprints (Children's titles) and others covered in mildew. Most importantly, I have found quite a few that had cracked discs! I'm sure running a cracked title through your player would tear that needle up pretty quickly!

I'm curious-were there any titles that were only ever released on CED? I collect 8-tracks, and part of the fun is that so much of that material was specific to that format, or additional material was added to an album to meet the running time restrictions of the tape.

[wa2ise]

Originally Posted by leadlike

I'm curious-were there any titles that were only ever released on CED? I collect 8-tracks, and part of the fun is that so much of that material was specific to that format, or additional material was added to an album to meet the running time restrictions of the tape.

As I used to work for RCA Labs back in the CED era (early to mid 80's) I acquired a fair number of test pressings. One such was a disc filled with about 2 hours footage of random TV shows RCA owned the copyrights to. As RCA owned NBC back then, this stuff was easy to come by.

I grew tired of lugging a few players and about 50 discs around every time I moved, so I sold the whole enchilada to a CED collector back in 1996. Via that CED magic web site. I imagine most of this stuff is still kicking around the CED collector community.

AT the RCA Labs I knew someone who was developing video games based on CED videodiscs. That the game console would drive a specially equipped player to do controlled groove skips to pick one of a few nearly concurrent video tracks (the disc had the usual spiral groove track, but the player could tell which video frames were which (codes encoded in the vertical interval) and the controller, knowing via a "standard" pattern, knows when and where to do groove skips, could quickly change video programs depending on what the video game player did. He was about half way into this scheme, then RCA management dumped the entire CED videodisc in the can... End of that.

[leadlike]

Wa2ise, did you ever happen to see any test pressings of CEDs on other media, such as the early metallized discs? How did the picture compare on these? Was the carbon-impregnated PVC disc a bad choice in the end? Any memories you can share of CED behind the scenes would be wonderful.

[wa2ise]

Originally Posted by leadlike

Wa2ise, did you ever happen to see any test pressings of CEDs on other media, such as the early metalized discs? How did the picture compare on these? Was the carbon-impregnated PVC disc a bad choice in the end?

I still have a couple of those metalized discs, but IIRC the groove size and pitch were different. I didn't have a way to play them, so I can't comment on the quality. I don't think the carbon PVC discs were a bad choice vs some other scheme, but probably the biggest issue was that the information layer was at the surface, exposed to crud in the enviroment, and impurities in the material itself. Laser discs and later on CDs and DVD the information layer is buried inside a clear coating, and wih enough error correction impurities are less of a problem. And no needle to get kicked aside. One thing RCA found earlier that that the discs would not last long if they were packaged like LP records, that people getting their fingers on them would quickly ruin them. Also the metal layer tended to peel off.

Everyone at the Labs knew that this thing had no real chance to become a success, despite all the marketing the marketing depts in New York City tried. Laserdisk had a full 4Mhz bandwidth video image, and had fewer problems with impurities. And then there was the VCR, which let people record and erase and record again. Though the video image was not that good. But anyone could make pre-recorded tapes of anything, including porn, which RCA was not gonna press into CED discs.

When they did pull the plug in 1984, surprisingly enough no layoffs happened at the RCA Lab. People got reassigned to other projects.

[old_tv_nut]

Zenith sold them (rebranded from whom, I don't recall) for a short time, and later there were a few in the building that employees could check out. I remember watching "Barbarella." I don't remember any "blue rain of static," and there probably was skipping, but I just don't recall.

When RCA demonstrated the system to potential business partners, they pointed out the comb filtering effects, believing that they were benigh enough for a consumer product. They had one movie clip involving a suspension bridge - the vertical wires were visible, but the diagonal ones faded out.

The CED player senses the minute capacitance changes due to pits in the groove by making the stylus and disc part of a microwave oscillator - the frequency is modulated, and an FM detectior can then get a strong signal out of such small changes. The oscillator has to work in the same "garbage" frequency band as early microwave ovens (915 MHz) so as not to cause interference to other devices. there was some concern that microwave ovens might cause interference in the player, but i don't know if that was sufficiently suppressed by sheilding.

The CED sound, being FM , was better than VHS linear track, but not better than VHS FM.

Colors can appear "washed out" for two reasons:
1) much poorer film-to-video transfer than today
2) low chroma bandwidth (reduces saturation on small objects and prevents well defined color contrast on vertical edges) (this problem is not too different from VHS)

[Eric H]

I passed on one of these at the Goodwill today, no more room for toys I don't need. I also passed on a nice Pioneer Laserdisc player at the SA.

[Trance88]

I just found out about the CED format last week. I had no clue that it was possible to put audio and video information on whats basically a vinyl record. Does anyone know the RPM of these discs??

[wa2ise]

Originally Posted by Trance88

Does anyone know the RPM of these discs??

One rotation has 8 video fields, so it's about 60/8 rotations per second, and thus it would be about 450 RPM. Early machines used an AC synchronous motor that spun the turntable at 1/8th of the 60Hz powerline frequency, thus yielding the 450 RPM. Later on, they used a direct drive scheme that was phase locked looped to spin the disc at the rate needed to get the frequency of either the chroma subcarrier, or the sound subcarrier correct off the disc. The chroma subcarrier was not recorded on the disc at the usual 3.58MHz, but as a "color under" frequency at around 1.53MHz, and there was an upconverter circuit to get it up to 3.58MHz. This would also allow the removal of any wow and flutter off the chroma subcarrier, as the conversion frequency oscillator could be varied to yield a steady 3.58 output subcarrier. Besides, the video bandwidth of the disc was only good to about 3MHz, lower than the 3.58MHz subcarrier. So this was a work-around for that as well.

[old_tv_nut]

"Color under" isn't quite the right term - it really was a subcarrier added to the luminance before FM modulation - hence the need for a comb filter. In tape systems like VHS, the luminance is on a separate FM carrer, and the chroma is direct analog at a lower frequency than the deviation range of the FM. The luma FM acts as a high frequency bias for the chroma. In the CED, the recording is strictly pits and lands, which can vary in frequency and duty cycle, but not in analog amplitude, so, the video tape type of color-under wouldn't work