MP3 CDs: a hybrid "format" that never existed, yet was surprisingly common
There was a time, about 20 years ago, when a pretty widespread trend took hold in the world of stereo equipment which I don’t think many people noticed or took advantage of. This aggressively 2004 bookshelf system from Panasonic features a five-disc CD changer, a couple of cassette decks, an auxiliary input and of course a radio tuner - all typical stuff of the time. But it also proudly displays MP3 in quite big letters number. Why? And why is it just the text MP3 without any specific branding or context? Well, that MP3 mark looks weird and non-official because it’s signifying a weird, non-official thing. It’s telling you this machine can play MP3 CDs. And this is by no means unique.
Here's a CD Walkman which also has MP3 written on it without context (in addition to Atrac3Plus. Sidenote: Sony. Stop trying to make Atrac happen. It’s not going to happen!). And aside from personal stereos, lots of cars made from the mid-2000’s up until they stopped putting CD players in them can also play MP3 CDs.
Now, while I’m sure some of you know what I mean by MP3 CDs, I imagine a lot of you don’t. So… what is that? Well, and here’s why the whole concept is a little strange, despite being fairly widely supported for quite a while, MP3 CDs were closer to a hack than anything else, and they weren’t actually a legitimate format. What do I mean by that? Well, I’ll get there but thanks to the relentless passage of time, I’m gonna have to explain some stuff for the youngin’s out there. Not that long ago, we used a thing called physical media. It was wild, when you wanted to play the latest hits you had to go to a store and buy music on cassette tapes or CDs! And then of course you had to use cassette players or CD players to listen to the music you’d just bought. It was a trying time, I don’t know how we made it.
But then came the Internet. Suddenly there was a distribution system for music which didn’t require going to a store. Or potentially other things which normally need to happen to get access to music but I’ll just ignore that. There was a problem, though. High-fidelity digital audio burns through what was at the time an absurd amount of data. The Compact Disc, the standard digital audio format which hit the scene in 1982, stores two channels of raw 16 bit audio samples taken 44,100 times every second, which means the datastream coming from one of these is about 1.5 million bits per second.
These days that’s child’s play, but back when the internet involved modems shrieking at each other over a telephone line, downloading a whole CD’s worth of data took more than an entire day. Time wasn’t the only issue, though. There was also where to put all that data. It’s easy to forget because now CDs are almost useless - my camera’s created dozens of CDs worth of data since I started recording! But back in the mid-’90s, compact discs were still the king of data storage. The CD-ROM, the data equivalent to the compact disc digital audio format created for computers, could hold 650 megabytes of data, with later revisions pushing that to 700.
And personal computers back then often had hard drives with smaller capacities than a single one of these. So it just wasn’t reasonable to download and store music from the internet. It would take way too long and eat up all your storage space. That was, of course, until compressed audio formats hit the scene. Much to the chagrin of audiophiles, some very smart engineers figured out that we don’t actually need a stream of raw audio samples to recreate music with decent fidelity. With quite a few tricks involving quite a lot of math and also insights into how we perceive sound, we found we could toss out a large majority of the data and still end up with more or less the same sounds as before.
Now there’s a whole host of people who were involved in research to this end, and rather than try to go over even a fraction of who they were and what they discovered and when, I’m just going to quickly do this: [drum kick] [mouth noises] OK, now that you’ve absorbed all that, let’s talk about MP3s. Officially known by the mouthfuls MPEG-1 Audio Layer III (and also MPEG-2 Audio Layer III), MP3 first hit the scene in 1992 as a way to efficiently encode audio alongside compressed digital video. While made with video in mind, since it was so data-frugal by the late ‘90s it had become the de facto standard format for compressed audio. And at the time, I imagine it felt like a miracle. MP3 could compress the datastream from audio CDs by a factor of 10 and still sound pretty good. Not as good as a CD, no, but pretty good.
That massive compression ratio reduced the download times for a CD’s worth of music on dial-up internet from a day to a few hours (with a fast enough modem, anyway) and meant you could store at least a few albums on your PC without too much worry. But nobody really wanted to listen to their music on their desktop computers. They wanted something more portable, so just as we had portable cassette players and portable CD players, portable MP3 players started hitting the scene. These were devices with rewritable data storage onboard which you’d load up with MP3 files from your computer, and then they’d play those files from their onboard storage through a headphone jack so you could listen to them. The first MP3 players were clunky and difficult to sync with a PC, and they hardly had any storage capacity (early ones might only have 32 megabytes of flash storage onboard, enough for one highly-compressed album).
But it was a pretty compelling idea to get music from the internet, load it onto a small little device, and take it with you. And as you probably already know, that idea was kicked into high gear by Apple with the release of the iPod in 2001. Now, the iPod (and, yes, this isn’t a first-gen iPod)... it’s not really relevant to this video, and much of its innovation wasn’t in the device itself but in iTunes and how Apple legitimized online music sales. But because of its success, the popularity of iTunes as a piece of music library management software was pretty huge, even among PC users.
There were plenty of competing programs out there, some of which I used. I was rocking one of these Rio MP3 players for a while. But I did eventually get an iPod, and for the purposes of this video I’m gonna use iTunes. So now, let’s fire up a PC you might have been using in 2004 and poke around in iTunes for a bit.
[Windows XP startup music] While of course you could buy and download music through iTunes, personally I hardly ever did that. We had a ton of CDs in my family (plus new CDs were still widely available back then) and iTunes could rather quickly rip those CDs onto your hard drive and convert them into MP3s in the process. That is, if you went into the settings and changed it from AAC.
Apple just loves being Apple and they decided to make that more obscure compressed audio format the default for iPods, though iPods could absolutely play MP3s and luckily I was smart enough back then to realize what a headache it would be to have my library encoded all appley. It’s not technically Apple-exclusive and it was slightly better than MP3 but it was nowhere near as widely supported so I just said no. Anyway, once set up you’d just load an audio CD in your computer's CD-ROM drive and iTunes would almost always correctly identify it and auto-populate all of the album, artist, and track information for you. This computer’s not doing that right now because it’s not connected to the internet as that would be a disaster. It needs the internet to populate that info because, fun fact, almost all audio CDs don’t actually have any sort of metadata on them so the way that auto-identification worked was by checking the disc’s table of contents to see how many tracks are on it as well as how long each of those tracks are against a database.
Astonishingly few commercially-made CDs have the exact same combination of track lengths so that worked as a functional fingerprint, and on the rare case there were duplicates, iTunes (or whatever other software you were using) would just ask you to pick which one it was. Pretty neat. And once the import process was complete, well you had a copy of that music in your library.
And this old version of iTunes really shows just how remarkable MP3 compression was. This single audio CD had just shy of 500 megabytes of data on there, and since this PC only has a 20 gigabyte hard drive, if we had simply imported this as uncompressed WAV files we’d be committing quite a chunk of the hard drive space to just one CD. But the compressed MP3s that iTunes created from that CD audio data are taking up just 68 megabytes, roughly 1/7th the original amount and that is with the files encoded at a slightly better than average 192 kilobits per second.
Now of course the next step for many people was to connect an iPod to the PC and have iTunes synchronize the data in your library with your iPod that way you had all this music with you on the go. But that wasn’t the only thing you could do. iTunes is just a piece of library software, and the actual MP3 files it creates are stored in folders on your PC. And if your PC had a CD burner, well now we’ve got some interesting possibilities. Because a blank CD-R could become an audio CD which would work in any CD player going back to 1982. But an audio CD can only hold 80 minutes of music.
A CD-ROM, on the other hand, can hold 700 megabytes of data, and you can put whatever data you like on it. See where this is going? Let’s pop in a blank CD-R. The computer recognizes it as a blank disc and asks me what I want to do with it. I’ll say open an explorer window so I can copy files to it. And why don’t I copy some of those folders full of MP3s? Each one is around 60 or 70 megabytes so I could fit, gosh, 10 full albums of music on one CD.
So let’s do it! And - woah. I forgot how clunky this was in XP. It doesn’t even show you how much data you’ve used up! You have to check that manually. Shoulda gotten a copy of Nero.
Oh, that’s right, these files are full of higher-quality MP3s at higher bitrates so we can’t quite fit so many on one disc but anyway, once I’ve filled it up, we can burn it to the disc. After the computer generates the disc image we get this old goodness. [CD-ROM drive spinning up with quite the drone] [ope, it dipped in speed a bit] [it did it again!] [now it's settled into a steady speed] Ahh, I miss that. Kind of. Once it’s finished burning those files to the disc, we have a CD-ROM.
A CD-ROM which just happens to contain a bunch of folders filled with MP3 files. Which means… we’ve just created an MP3 CD. Now, remember how I said this wasn’t a legit format? That’s because it’s not! This is just a CD which we asked the computer to write files to! It was written in a format: the disc follows the Yellow Book standard for CD-ROM as well as ISOs 9660 and/or 13490 for its file system. But the actual files we burned to it could have been anything at all! We could have put photos on here, or text documents, executable programs, even video files. The only reason this is an MP3 CD is that we decided to fill it up with a bunch of MP3 files. Now, if I popped this disc into another computer, it would be able to see those files and copy them off the disc.
But if I put this disc into a CD player, it won’t work. An ordinary CD player only plays discs that conform to the Red Book standard which defines the Compact Disc Digital Audio format. That’s what this logo is, it’s a compatibility mark for compact discs and the Digital Audio below indicates compatibility with the original audio CD format circa 1982. A computer can burn audio CDs, and iTunes offered an easy way to do that.
But those only hold 80 minutes of music. This disc contains much more than that, but as far as what the disc actually is... well it’s just a bucket of random files. And CD players don’t know what to do with that. Some might try to play the disc, but it will either produce no sound at all or, if it’s old enough that it predates the CD-ROM, the onboard DAC might try and decode the bits it's reading, but their structure is nonsense and so it will just produce very unpleasant noises. [very unpleasant noises] But this stereo system doesn’t have an ordinary CD player.
Yes, it features the Compact Disc Digital Audio compatibility mark and it will play standard audio CDs just fine. But when we put in the disc we burned with those MP3 files… it can actually read it and see what’s on there! It takes a little while, but it understands the file system, shows the folder names on the display, lets me navigate between folders using the remote (though it refers to them as “albums”), and of course it can play the music while also displaying the track titles. That means that, in a way, this thing is actually an MP3 player - but rather than use a bit of flash storage or a tiny hard drive, its data storage media is CD-ROM. And unless you’re the kind of nerd to read the manual, you very well might not have known it could do that! I had no idea this was a thing despite having this very stereo system in my bedroom until I got my first car. Its stereo also had MP3 inexplicably written on it which I would have just passed off as it bragging about having an auxiliary input jack. That was a big deal back when cassette adapters were the norm.
But it didn’t just say MP3, it also said WMA. That stood for Windows Media Audio, another compressed audio format that Microsoft was trying desperately to make happen and once I realized it must be talking about some ability to play those file formats, I was confused. That car’s stereo didn't have a USB input or anything like that so I opened its owner’s manual to the section on the stereo to see what the heck it was talking about and that’s when and how I learned what MP3 CDs are.
It had a nice explanation of how many folders could be on the disc, which bitrates the stereo supported, and how to navigate them and my mind was frickin blown! I had all this music on my computer for my iPod and it was all stored as MP3s in nice, neat little folders, and you’re telling me that if I just burned some of those files to a CD my car could read the disc and play them? That was wild! I mean, consider the iPod Shuffle. That thing hit the scene in 2005 with only 512 megabytes of storage, and a single CD-R could hold more data than that. So just burning one MP3 CD and keeping it in my car’s stereo would be like having a permanent iPod shuffle just for my car which I only spent $0.50 on. And then, I could make a whole new iPod’s worth of playlists with another $0.50 blank CD.
I made a lot of these discs. I soon figured out that you could add numbers to the beginning of the folder names which would enforce playback in a particular order. This one here has 10 different They Might Be Giants albums arranged chronologically.
And I mean, this was awesome! I loved being able to keep just a few CDs in the car which stored hours and hours of my music, especially since I could use the car’s controls and not mess with my tiny iPod while driving. Remember when physical controls in cars were considered a good thing? I remember. And, uh, for those concerned audiophiles out there? Since it was for playing in a Honda Civic it’s not like the audio fidelity was that critical anyway. I honestly had no idea that this was such a widely-supported feature - I thought it was just a neat thing my car could do.
It was at least a year into having that car that I finally noticed the MP3 mark on my bedroom stereo. Intrigued, I popped in one of the discs I made for the car, watched the alphanumeric display come to life and start scrolling the track info, and let out the most flabbergasted “would ya look at that” I could muster. Just the fact that it could do this is impressive enough, but this isn’t just a single-disc CD player, remember, it’s a 5-disc changer. It’s got a slightly terrifying design where there’s a single disc tray and adding another disc involves a little dance where it holds each disc in an internal stack and then spits the empty tray back out so it looks like it keeps eating your CDs but anyway with 5 CDs at its disposal this thing kinda sorta has 3.5 gigabytes of storage capacity. That’s within spitting distance of the iPod Mini which came out the same year as this stereo. So I mean if you wanted to you could mirror almost your entire iPod library with just a few dollars worth of blank CDs.
Obviously the interface here is less than ideal and things like shuffling your entire library doesn’t work when it’s across five discs but I mean… it’s still impressive. And this will shuffle through a single disc if you like. It even does a little animation when it picks the next track. Which brings me back to this CD Walkman. It, too, can read MP3 CDs and it features dedicated folder buttons for navigating around the disc. It takes it a while to figure out what exactly it’s reading when you first pop in a disc, but once it’s got its head on straight you can quite easily move from folder to folder, and so long as you don’t open it up between play sessions it will resume quickly from sleep.
And as a bonus, because MP3 files are so small, it only has to spin the disc for a few seconds at a time roughly once a minute to fill up its internal data buffer, which helps its battery life a lot. Honestly, if I knew about MP3 CDs when I first got my MP3 player... I might have been tempted by one of these instead. But on that note - it’s time to step back in time a little farther. So far I've been talking about this as a mid-2000’s phenomenon - and I think that’s broadly correct.
But MP3 CD players started showing up in the late ‘90s. Well, the very late ‘90s - this Wired article from September 1999 talks about what is claimed to be the first portable CD player which can read MP3 files. In fact it even says it’s “the first MP3 hardware device that requires no computer or Internet connection” though… that’s something of a stretch. Anyway, I would argue that those early devices just… didn’t get noticed. Only turbo-nerd tech enthusiasts who knew what MP3s were would have their eyes on a product like this. Portable CD players were quite common by 1999 but having a CD burner in your PC was still fairly exotic.
And if you had one you were most likely using it to make data backups, perhaps copies of… stuff for your friends, or standard audio CDs to play in the car or the Discman you already owned. Seeking out a standalone CD player capable of reading MP3 files was solidly in tech enthusiast, early adopter territory back in 1999. And then, well, the idea quickly became yesterday’s jam. By the time MP3s started hitting the mainstream, dedicated MP3 players you synced with your PC were the hot item. They seemed like the natural progression of things, and portable CD players were old hat.
I was a kid back then and yeah I definitely felt like the uncool kid rocking my black and neon green CD Walkman - that one - when everybody else had MP3 players or iPods. That was until I pestered my parents into getting me this. Peer pressure’s a nasty thing, uh, so let me just walk back what I said a little while ago because even if I had known about MP3 CDs I probably would have felt a little awkward using them. And I probably would have gotten into weird arguments defending them so thank god I dodged that bullet.
But now I’m an adult, at least according to my driver’s license, so I don’t get into weird arguments defending my tech choices anymore. Nope. Definitely not. Anyway, as time went on, MP3s as well as CD burning became quite common. And before long, the chipsets required to decode MP3 files for playback got cheap enough that it was fairly trivial for manufacturers to include that functionality in a CD player. If it’s gonna play audio CDs, it’s gonna have all the hardware necessary to read a CD-ROM, so to play MP3 CDs required little more than a few tweaks to the firmware and an extra chip or two.
But that added functionality got, as far as I can tell, very little fanfare. So unless you knew to look for it, it largely flew under the radar. My personal theory is that most manufacturers were a little afraid of touting a feature which could make record labels angry. But that’s just speculation. And to be honest, I really have no idea how common support for MP3 CD playback actually was in the grand scheme.
DVD players were extremely likely to be able to play them - as a rule they have MP3 decoding hardware since they play MPEG2 video, so all they needed was some sort of UI to manage navigating the disc. As a matter of fact if you didn’t know this already, DVD players will read all sorts of files. I remember popping in a CD with the JPEGs written to it from a vacation and the DVD player produced an instant slideshow on the TV. Oh, and if you burn a bunch of MP3 files to a blank DVD-R, well then you’ve made an MP3 DVD! And a fair number of cars have DVD-ROM drives for updating navigation maps and some of them will also play back MP3s so you might be able to make a nearly 5 gigabyte store of music for your car. If you still have an optical drive hanging around.
But as far as how common this feature was in plain ol’ stereo systems… it’s almost impossible to know. If you go looking for stereo systems on eBay from around this time period or later, you’ll find a lot of confusing and conflicting things. Once CD burning had gone mainstream, a lot of manufacturers started putting CD-R/RW compatible marks on their stuff but that can be misleading. Mainly that was important for rewritable discs: the signal the laser gets back from a CD-RW is very weak compared to a standard CD or CD-R, so most CD players can’t read a CD-RW disc, even if what’s on there is standard audio data.
If a machine says it’s CD-RW compatible, that just means its laser can read those discs without an issue, but it doesn't mean it will play MP3 files. And it took me almost no time at all to find a Sony unit for sale, new in box, which makes no mention of the fact that it can play back MP3 files written to a disc. I had to look in its manual to find out that it could. And that’s honestly what I find so weird and fascinating about this whole thing. To the designers and engineers of stereo equipment back then, adding MP3 playback functionality was a pretty big no-brainer if you’re gonna have a CD drive at your disposal.
But as far as I can tell, not a lot of people knew about that functionality. In hindsight I don’t think that’s all that surprising: we tend to compartmentalize things in our minds and CDs and CD players are one thing, MP3s and MP3 players are another, and a CD-ROM full of MP3s is in a weird grey area between them which doesn’t parse as anything useful, unless you wanted to share some MP3 files around. And that’s definitely where my brain was until my car forced my curiosity to finally kick in and I read the freaking manual.
Now, those of you who burned CDs using iTunes back in the day might remember that MP3 CDs were an option it gave you in the settings. I definitely didn’t notice that! Or if I did I didn’t know what it was trying to say. However, quite unfortunately when I tested this function the discs it created didn’t have any folder structure. It would just take the playlist and burn it to the disc in a single folder with each individual song given a number prefix to enforce playback order, so the folder buttons here (as well as on the stereo and in the car) would be completely useless. The “data CD” option does the same thing. That might have changed in later versions of iTunes, I’m honestly not sure and also am honestly not willing to find out because sifting through iTunes version history is a pain.
Additionally, if the files weren’t already MP3s, iTunes would not convert them on the fly and as far as I can tell that never changed (which, given the whole DRM situation with stuff you could buy on iTunes makes sense). Regardless if you knew your way around Windows it was much easier to just create these manually and that would give you more control on the player end. I imagine it was the same situation for Mac OS and Linux, too. And as a treat, I will spare you the joke I wrote about audio drivers. See? I’m learning! But that’s an excellent segue into some of the problems with MP3 CDs.
Because it was never a real format, there was never a standard way to structure the data on the disc. It seems as though folders as an analog to albums was generally the most widely-supported structure, but compatibility issues with certain hardware devices could occur if the data wasn’t arranged on the disc in a compatible way. So a theoretical machine might be able to read the files, but it might play in the wrong order. Or there could be files in subfolders which some particular players won’t be able to see. To be honest though… I think that’s the only major flaw with the quasi-format.
One smaller flaw was that on the player end, gapless playback was unfortunately quite rare (this stereo produces a full two seconds of blank between every song which on some albums is very annoying) but that’s more of an implementation issue than anything else. I’ve also noticed that the Walkman, on occasion, waits just a fraction of a second too long to spin the disc up between reads so there are sometimes tiny little blips of audio dropouts. Though that could very well be an issue with this thing’s age or could even be something as simple as weak batteries. You might wonder, were there ever any commercially-made MP3 CDs? And the answer to that is yes, actually! Audiobooks took up the mantle pretty quickly because, well to be honest, they were a perfect fit. If a book needed 10 hours of spoken words, then it would need at least 8 audio CDs.
But you could easily cram all that onto a single MP3 CD, especially because it would be in mono and it’s not like you need a ton and bandwidth for speech. [audio quality degrades slightly] Here’s what 64 kpbs mono MP3 sounds like, and while you can definitely tell there’s some compression going on, it’s perfectly fine for speech. Plus a single CD will hold just over 24 hours of this quality audio. So even very lengthy titles could fit on a single disc. While many people would just pop those CDs into their computer and then copy the files onto an MP3 player, if you had a CD player like this or that - it could just play them. And there were also music compilations that were sold from time to time on MP3 CDs.
My perusal of eBay suggests that this was much more common in markets outside the US, and also some of them don’t seem that… legit. Uh, but that Wired article about the first portable MP3-compatible CD player suggests that there were a few MP3 CDs being sold at the time. Though to be honest I am also a bit skeptical of the legitimacy of those.
I’m pretty sure that aside from audiobooks, commercially-sold MP3 CDs were quite rare. Because, well, unless you know what that is, it’s going to be confusing and potentially require a computer to play those files or move them onto an MP3 player. Not the most user-friendly experience. In a way, the MP3 CD exists in something of a liminal space which uncovers some of our quirks in how we imagine media.
A standard CD is really just a music-delivery mechanism. It’s less of an object in itself and more of a vessel. So using an already tweaked version of the same vessel to deliver music but in a new way is both obvious and yet confusing. It blurs the line between CD-ROM and CD-audio because, well, it’s both and yet also neither! And I find that fascinating. I know I’m a weird nerd, but still! I find myself wondering what the world might have looked like if this idea had gotten more traction. Perhaps those tiny portable CD players meant to play the 8cm mini-CDs might have reappeared and come into vogue.
The 210 megabytes you can squeeze on one of those little guys would actually be quite useful for MP3s. And if those theoretical devices could read DVD media, you’d have 1.4 gigabyte discs at your disposal. You could even make them double-sided. And speaking of DVDs, dual-layer discs held some 8.5 gigabytes -
with modern video compression, that’s actually quite a lot of space. Makes me wonder if we could have had an h.264 DVD format holding 1080P video. It’d make the cinephiles pretty mad, though. Oh, and to close out this video - if you haven’t already been made aware of this, you should know that writable optical media can degrade a lot faster than you might have thought. So if you have a bunch of burned discs lying around and any of them are important to you you should back them up as soon as possible. Some may have already degraded to the point of not being readable.
A lot of that depends on the storage conditions, so they might be fine but they won’t last forever. So if you’ve got a PC with a working optical drive, you might want to set aside some time for a project day. I’m overdue for that myself. Alrighty, well, that’s all, folks! ♫ compressedly smooth jazz ♫ Here’s a CD walkman from… what? As a way to enficiently - Eniciently… ecode! ...and to realize what a headache it would be to have my library encolded all… ahh, encoded! …should probably open iTunes, huh? Ah this is not, this is- Take your time. Uh, once it’s finished burning the disc to the files...
Ahhh haha! Now if I popped this disc into another comPUTer. What the heck hapened there? I’ve also noticed that on the walkman, on occasion it wai - eh. So, using an already twhweaked --- [whistles] So, how many of you knew about this already? I think the people who regularly watch this channel are far more likely than average to have run across this before, but back when I was a youngin' the people I knew who were burning mix CDs were making standard audio CDs. I really never ran across this until the end of high school, maybe college! Anyway, beep boop.
2024-10-17 20:58