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Today, I want to show you a pretty weird device.

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This hi-fi component lookin’ thing from Sony is a

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DIGITAL AUDIO PROCESSOR

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and it’s got a rather strange assortment of connections on the back.

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We have audio in and out, pretty normal, but also… video in and out?

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Annnnd… monitor out?

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Copy out?

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Well, I suppose to figure out what this does
we should hook it up to an audio source and a TV.

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Why, that’s as easy as a jumpcut!

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With my microphone wired to its audio input
and a TV hooked up to its video output,

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we find that this supposed “digital audio processor”
is doing something quite odd.

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Before we get a closer look, be aware that things
are going to get somewhat flickery

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and that will continue throughout much of this video.

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It’s more like rapidly changing patterns than it is a flickering image,

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but if that sounds bothersome to you…
you may want to skip this one.

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At first glance it appears as though we’re
looking at the snow of a TV tuned to a dead channel,

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but there’s definitely some structure to what’s on the screen,
and it’s responding to my voice.

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Let’s take a look at a raw video feed.

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Good luck, YouTube compression.

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As perhaps you can see, similar patterns appear
depending on what exactly my voice is doing.

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If I exteeeend vooowelll sounds weee seeee distreeeeet
blocky shapes come and go.

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And if the spicy snap of sibilance saturates the soundscape,

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we see some spans of snowier snow.

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How ‘bout, instead of my voice, we use a
signal generator for a sine-wave sweep?

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[an ascending sine wave sweep]

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Interesting.

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Let’s do that again but with sawtooth waves.

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[an ascending sawtooth-wave seep]

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Similar, but spiky!

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Now, if a device which turns sound into this
weird imagery seems pretty pointless,

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that’s because these visuals are not the point of it at all.

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Well, ok technically yes they are but you wouldn’t ordinarily be looking at them.

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Devices like this are more generically known as PCM adapters,

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and the mess you’re looking at is actually digital audio data.

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This is what it would look like if you took
the analog sound signal from my microphone,

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digitized it using 16 bit pulse-code modulation,

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then encoded the resulting datasteam as high-low pulses tucked neatly into the scanlines of an NTSC television signal.

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And the reason I can say that with confidence
is because that’s precisely what’s goin’ on here.

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Once again I have friend of the channel James Colvard
to thank for lending this fascinating thing to me.

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This device represents what was for many years

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the easiest solution to the biggest problem facing digital sound reproduction.

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On the surface, digital sound should be easy
as the concepts behind it are actually pretty straightforward.

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At the risk of oversimplifying,
you can make digital sound happen with only two chips:

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the first one, the analog-to-digital converter,

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takes a single input from a microphone or whatever other analog source you like and,

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through a bunch of comparators and logic gates and junk

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it will spit out a binary integer across several outputs.

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To give an example, if we give this theoretical
8-bit ADC an input signal of 700 millivolts,

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that results in these output pins going high
- a result of 01101011.

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And something that I want to stress here is
that while we could convert this result into base-10 numbers,

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there’s no need to do that -
we’re just going to send this sequence of bits to a second chip.

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That chip, the digital-to-analog converter (or DAC),

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has a digital input side and an analog output side.

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To reproduce the original signal intensity,
all we need to do is put the right bits into the right slots.

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So, with our theoretical 8-bit system,

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applying voltage to the pins in the same pattern the ADC just gave us 
(low high high low high low high high)

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will result in thIS chip producing an output signal of 700 millivolts.

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All we need to do is ensure that these two
chips speak the same language - as in,

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the same sequences of bits produced by the ADC
are mapped to the same signal outputs in a matching DAC.

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And that’s done at the hardware design level.

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This particular flavor of digital sound is called pulse-code modulation or PCM.

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The analog-to-digital converter takes an instantaneous
snapshot of the analog input’s signal strength

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and spits out a code.

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Then the digital-to-analog converter takes
that code and spits out an analog output

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(which you might call a pulse) 
that matches the original snapshot.

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It’s actually pretty easy,
but the problem is that to reproduce sound,

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you need to take a lot of snapshots of the signal.

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We usually call those snapshots samples,

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and to faithfully reproduce sound
you need to take a few dozen thousand samples every second.

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No big deal.

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Technically, that truly is not that big of a deal.

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We can take samples from the ADC very frequently

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and it’s not a big challenge to make a DAC
which can ingest those samples just as fast.

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We had the tech to do that readily available in the 1960’s.

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Trouble is, while it might be easy to make
data from sound and sound from data,

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doing that in real-time is just building an overly-complicated radio.

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Digital sound wouldn't have much of a point

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unless we can store the pulse-code data somewhere to be read back later.

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And that step ain’t easy.

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An analog-to-digital converter spitting out
pulse code data may not be doing anything all that complex,

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but it produces an utterly unmanageable quantity of data.

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These days, of course, it’s a breeze,
but when digital sound was getting off the ground this was a heckuva problem.

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The very first PCM audio recorder was built by NHK in Japan back in 1967.

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This single-channel recorder had a sampling rate of 30 kilohertz
 and took 12 bit samples.

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That’s a bit shy of modern standards,
but thanks to the Nyquist-Shannon Sampling Theorem,

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we know that it could reproduce sounds up to 15 kHz,
which is about where FM radio tops out.

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While there most definitely were computers
that handled and stored digital data back in 1967,

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nothing remotely suitable for digital audio was available on the market.

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I mean, punch cards? Forget that.

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9-track tape?

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That might work, but NHK’s device would
completely fill up a 2400 foot tape in less than 17 minutes.

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And while hard drives did exist,

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even if you wanted to shell out the however many tens of thousands of dollars it took to buy one of IBM’s room-sized monsters,

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NHK’s singl-channel PCM recorder
would fill up the entire nine-disk array in less than two hours.

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That just ain’t gonna work!

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However, NHK didn’t need the complexity of a file system
or the random-access capabilities of true “data storage” -

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they just needed something that could write down a whole bunch of binary
really really fast, and then read it back just as quickly.

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As it turned out, although it would need a little modification,

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an existing technology would fit the bill just fine.

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And it was one that NHK, being Japan’s national broadcaster, 
had really easy access to:

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a simple videotape recorder.

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See, you need tons of signal bandwidth for storing video signals.

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Analog video is made up of very rapidly-drawn lines.

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With 525 lines per video frame and 30 frames
being displayed every second,

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an ordinary TV draws 15,750 lines every second.

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Videotape recorders, through the use of spinning
heads that fly across long slices of magnetic tape

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(as well as a whole bunch of clever circuitry)

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were able to record those signals and
reproduce television images with decent fidelity.

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But there’s no rule saying what those images have to be!

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If you slap some high-low pulses across the video scanlines,

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that might look like a bunch of white and black spots to your eyes,

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but to the right circuit that looks like bits.

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So, NHK rigged up their PCM encoder to spit out the sample data produced by its ADC as a sequence of high-low pulses,

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then carefully timed them to match the video characteristics
of a black and white television signal.

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They hooked that contraption up to an ordinary
videotape recorder, and suddenly they had a practical way to store digital audio data.

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To retrieve it, the videotape was rewound to the start of the program
and the recorder was set to play mode.

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Now, the PCM recorder became a PCM decoder,
recovering the bitstream coming from the videotape,

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sending it to a DAC, and then finally the
digital sound was heard again.

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And that’s precisely what this thing from Sony... is.

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This is the exact same idea as NHK’s original PCM recorder concept,

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though updated with better capabilities on account of being from 1983.

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This takes a stereo analog audio input,

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digitizes it using 14 or 16 bit pulse-code modulation
at a sampling rate of 44.056 kilohertz

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(which might sound kinda weird but hold your horses we’ll get to that bit),

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and then spits out the resulting data across the scan lines of a video signal.

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Every one of those lines you see contains the data for six audio samples,
three for each channel,

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as well as a bit of formatting.

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Hook this thing’s video output up to a VCR and,
as far as the VCR knows,

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you’re just trying to record a weird TV program.

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Though it may question your taste, it’ll record it just fine.

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And you now have a videocassette which contains digital audio data.

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That on its own isn’t super useful, of course,
but this thing works in reverse, too!

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Rewind the tape you just created, hit play on the VCR,

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and now it’s looking at its video input
hoping to see some high-low pulses it can understand.

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If it finds them it starts decoding them and
sends the raw data through a buffer,

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and then to its digital-to-analog converter which reproduces
the stored sound through the stereo audio output.

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[a brief bit of garbled sound, then music of startingly good fidelity]

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And you have just experienced an effective method of creating and reproducing digital audio recordings using an ordinary videocassette recorder!

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This may seem convoluted,
in no small part because it absolutely is,

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but this is how digital audio worked for a very long time.

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Remember, we had the capability to record digital sound back in 1967,

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but the compact disc - the first truly digital audio format

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(well, other than piano music) -

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wouldn’t hit the market until 1982.

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And CDs had to resort to friggin lasers and
precision optics reading microscopic bumps on a shiny silver disc!

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Until that tech was mature, with very few exceptions high-fidelity 
digital sound reproduction relied on videotape recorders to be possible.

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It was the only reasonable way to handle so much data so quickly.

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But this wasn’t as easy as it might seem.

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Digital audio and videotape are not a perfect match
because the video signal isn’t actually continuous.

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Every field of video starts with a blanking interval which we can’t store any data in.

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And in fact, every video line also starts with a short blanking interval.

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But we can’t have gaps in the data -
audio sample data needs to be perfectly continuous.

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So, to deal with this, the adapter uses a buffer.

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When recording onto a tape, the continuous samples
coming from the ADC are briefly held in memory.

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The samples will pile up during the blanking intervals,
but once we’re past them and able to write data again,

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they’re quickly spat out in the six-sample chunks on each line.

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By the end of the video field, we’re caught up.

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During playback, of course, the opposite happens -
- as the samples come in, the samples get stored in a buffer

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so that the DAC can decode them sequentially without any gaps.

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Then there’s the issue of errors.

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No videotape recording is flawless - bad spots
on the tape will cause signal dropouts,

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and while they’re usually not much of a big deal when watching a movie,
the bits we’re dealing with here are teeny tiny.

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Even just the littlest blip could flip a bit,
so we’ll need some way to deal with that.

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And it turns out we have one!

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Look closely at the structure on-screen:

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we know there are six samples across every line, and we can see six clear sections spanning about the first 3/4s of the screen.

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But what’s all this then?

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Could it be some sort of checksum for error correction?

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Well, basically yes.

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I was finding frustratingly little information
on the technical specs of the data recording scheme here, but

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I did find this 1977 patent which talks about cyclic redundancy check words
getting added to the data.

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So that’s probably what that is.

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Some sorta math.

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And it works quite well!

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This modern VCR has various on-screen display elements,

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and despite plopping a big ol’ PLAY symbol in the top-right corner
and obscuring quite a bit of the bits,

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nothing sounds amiss when it’s up there.

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[music where nothing sounds amiss]

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Stray video dropouts can eat up entire lines
but I don’t even notice a blip in the sound when that happens.

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Actually, several lines can get corrupted before you hear an issue.

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[music which is mostly fine but stutters
or drops out briefly with big blips on the screen]

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Hi, I have an editor’s note!

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Though I don’t have concrete specifics,
I did find some promotional copy

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for an earlier PCM adapter of Sony’s and was able to confirm
that the data is interleaved between television scan lines.

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I don’t know exactly how, but shuffling
the data around and not recording it sequentially,

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along with the help of those cyclic redundancy
check codes getting tossed in with the data,

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allows it to recover from pretty gnarly video issues.

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And, like the compact disc, it has a system
to interpolate missing data

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to mask when large sections of it are not recoverable.

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It’s honestly quite impressive.

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As it happens, PCM adapters like this,

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along with the professional-grade U-matic videotape format,

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had a big part in the development of the compact disc.

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The objectively pretty weird 44.1 kilohertz sampling rate of compact disc digital audio happened because different parts of the world used different video standards.

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When developing their professional PCM adapters,

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Sony wanted to use a sample rate that would work
regardless of where you were, and 44.1 kHz

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(that was three samples per video line across 14,700 visible lines per second)

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represented the best possible fit between NTSC and PAL equipment.

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Trying to squeeze any more samples in would risk
part of the data ending up in the vertical blanking interval.

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So, 44.1 kilohertz became the de-facto standard for PCM adapters,

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and was then incorporated as an official standard with the compact disc.

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But wait a second.

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Earlier me said that this thing runs at 44.056 kilohertz.

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That’s 0.1% less than 44.1.

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Explain the discrepancy!

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Well, see,

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Sony’s professional PCM equipment of the NTSC flavor
used videotape recorders that operated in black and white mode.

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But this is a consumer PCM adapter meant to
work with consumer VCRs,

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and those VCRs record color TV.

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And, for reasons we don’t need to get into here,

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00:17:30,130 --> 00:17:36,600
color TV runs at 29.97 frames per second rather than 30.

212
00:17:36,600 --> 00:17:40,187
This thing still records six samples on every line of video,

213
00:17:40,187 --> 00:17:48,267
but those lines come in ever so slightly less often
and thus the sampling rate is a teeny bit slower.

214
00:17:48,267 --> 00:17:50,477
And now, here’s where I go

215
00:17:50,477 --> 00:17:52,151
“huh?”

216
00:17:52,151 --> 00:17:56,876
See, I have a pretty fundamental question regarding this unit.

217
00:17:57,776 --> 00:17:59,398
Why does it exist‽

218
00:18:00,236 --> 00:18:04,350
I knew encoding digital sound onto videotape was a thing we did,

219
00:18:04,350 --> 00:18:08,411
and I knew the story of U-matic tapes being important to CDs.

220
00:18:08,411 --> 00:18:14,484
But I always imagined PCM adapters as a decidedly
professional piece of equipment.

221
00:18:14,484 --> 00:18:16,903
Which this is clearly not.

222
00:18:16,903 --> 00:18:18,736
I mean, it’s not beige,

223
00:18:18,736 --> 00:18:20,633
it has normal RCA jacks,

224
00:18:20,633 --> 00:18:23,790
and it’s designed to work with consumer VCRs.

225
00:18:23,790 --> 00:18:29,881
Of course Sony would prefer that you hook this up to a Betamax deck,
but it works just fine with VHS machines, too,

226
00:18:29,881 --> 00:18:31,467
as you’ve seen.

227
00:18:31,467 --> 00:18:33,963
And it’s not like this was a one-off product —

228
00:18:33,963 --> 00:18:40,171
Sony had an entire line of consumer PCM adapters,
and this was by no means their first model.

229
00:18:40,171 --> 00:18:43,175
In fact, I think it might be the last.

230
00:18:43,175 --> 00:18:46,787
But you know what’s perhaps the strangest part of all this?

231
00:18:46,787 --> 00:18:53,281
The very first PCM adapter Sony ever made was a consumer product!

232
00:18:53,281 --> 00:18:56,083
Sony’s famous PCM-1600,

233
00:18:56,083 --> 00:19:03,290
the one that worked with U-matic VCRs, introduced 16 bit recording,
and cemented the standards for the upcoming compact disc,

234
00:19:03,290 --> 00:19:06,583
was released in 1978.

235
00:19:06,583 --> 00:19:15,366
But Sony’s PCM-1 was sold in 1977 as an accessory to Betamax home VCRs.

236
00:19:15,366 --> 00:19:19,884
It cost a cool $2000, and it did pretty much exactly what this thing does -

237
00:19:19,884 --> 00:19:22,044
just six years earlier.

238
00:19:22,044 --> 00:19:26,024
And when I learned this, a memory was unlocked.

239
00:19:26,024 --> 00:19:29,952
You’ve seen this ancient Betamax machine in several prior videos.

240
00:19:29,952 --> 00:19:35,679
It’s from 1979, so the PCM-1 had been available for purchase for a while.

241
00:19:35,679 --> 00:19:40,038
And under this little cover in the back is a switch marked

242
00:19:40,038 --> 00:19:41,806
“PCM”

243
00:19:41,806 --> 00:19:48,088
That’s there to disable some of this machine’s image-enhancing features
like dropout compensation.

244
00:19:48,088 --> 00:19:53,233
Those are great for video but can apparently
mess up the data encoded in video lines,

245
00:19:53,233 --> 00:20:00,169
so if you happen to have bought one of Sony’s PCM adapters,
you’ll want to flip this switch when using it.

246
00:20:00,169 --> 00:20:02,400
Of course, I had to try this out.

247
00:20:02,400 --> 00:20:05,337
I hooked the adapter up to this old tank of a thing,

248
00:20:05,337 --> 00:20:06,675
made a test recording,

249
00:20:06,675 --> 00:20:07,913
played it back

250
00:20:07,913 --> 00:20:13,067
and was frankly blown away at what I was witnessing.
[click of buttons, head drum spins up]

251
00:20:13,293 --> 00:20:19,451
[sudden guitar music]

252
00:20:19,451 --> 00:20:23,476
This is a very early home videocassette recorder.

253
00:20:23,476 --> 00:20:28,318
When this thing was new,
almost nobody had heard a real digital sound recording,

254
00:20:28,318 --> 00:20:31,684
and the compact disc was still three years away.

255
00:20:31,684 --> 00:20:38,498
Yet this machine was designed from the beginning
to support digital sound recording!

256
00:20:38,498 --> 00:20:44,647
It’s wild, and honestly this is officially what impresses me most about Betamax.

257
00:20:46,229 --> 00:20:50,000
[a nice jazz piano composition]

258
00:21:11,979 --> 00:21:15,293
Oh, by the way, wanna see what happens when you hit pause?

259
00:21:15,634 --> 00:21:17,717
Fair warning, it’s unpleasant.

260
00:21:17,717 --> 00:21:22,355
[Music]

261
00:21:22,355 --> 00:21:26,790
[brrrp - brbrbrbrbrbrbbrbrbrbrbbrbrbrbrbr]

262
00:21:26,790 --> 00:21:35,020
This shows that although the data does have a lot of formatting and error-correction,
it’s not as if every video frame needs to be perfect.

263
00:21:35,020 --> 00:21:38,724
The adapter will try its best to decode whatever it sees,

264
00:21:38,724 --> 00:21:43,265
and in this case it’s decoding the same frame of video over and over again.

265
00:21:43,265 --> 00:21:47,463
So you hear the same snippet of audio over and over again.

266
00:21:47,463 --> 00:21:51,083
[rapid clicking and popping]

267
00:21:51,083 --> 00:21:53,684
And when you try and fast-forward through the tape,

268
00:21:53,684 --> 00:21:59,604
it decodes snippets here and there
which sort-of help you figure out where you are in the recording.

269
00:21:59,604 --> 00:22:04,103
But, how well that works will undoubtedly depend on the VCR.

270
00:22:04,724 --> 00:22:09,749
[a lot of clicking with the occasional bout of intelligible music]

271
00:22:36,196 --> 00:22:38,561
Another fun thing is what happened here:

272
00:22:38,561 --> 00:22:44,243
I didn’t realize that I was recording in Beta-III speed
when I first started this test recording,

273
00:22:44,243 --> 00:22:46,893
and although I quickly switched back to Beta-II,

274
00:22:46,893 --> 00:22:51,736
because of where the tracking pulses are on
the tape compared to the video signal,

275
00:22:51,736 --> 00:22:55,005
for a brief while the machine’s running too slowly.

276
00:22:55,005 --> 00:23:03,632
But the adapter still valiantly tries to do its job - you can clearly hear an old
Warner Brothers home video intro happening here,

277
00:23:03,632 --> 00:23:06,229
only it’s very not-right.

278
00:23:06,229 --> 00:23:10,437
That is, until the VCR finally switches to the correct playback speed.

279
00:23:10,437 --> 00:23:17,281
[clicks, then very stuttery and slow music]

280
00:23:27,210 --> 00:23:36,851
But as much as I’m genuinely impressed at the feat of home PCM recording in 1977,
I can’t stop myself from asking -

281
00:23:36,851 --> 00:23:41,404
why on Earth would anyone buy one of these?

282
00:23:41,404 --> 00:23:45,178
I mean, in my heart of hearts I know why:

283
00:23:45,178 --> 00:23:47,940
to impress your audiophile friends, of course.

284
00:23:47,940 --> 00:23:56,816
But without your own full-on recording studio for capturing real live music,
there are exactly two things you might do with this:

285
00:23:56,816 --> 00:24:02,473
record programs from the radio or make copies of a record album of some kind.

286
00:24:02,473 --> 00:24:07,488
For making radio recordings, this thing is overkill to the extreme.

287
00:24:07,488 --> 00:24:13,960
Even if you had the best FM tuner in the business
with an antenna that can pick up tunes from the moon,

288
00:24:13,960 --> 00:24:20,389
FM radio just ain’t that high-fidelity
and a decent cassette deck would capture it just fine.

289
00:24:20,389 --> 00:24:23,712
And if all you want is a copy of somebody else’s record,

290
00:24:23,712 --> 00:24:26,867
there are much easier ways to go about that.

291
00:24:26,867 --> 00:24:29,997
Like, for instance, the aforementioned cassette deck.

292
00:24:29,997 --> 00:24:34,940
Or if that’s not enough fidelity for you,
get an open-reel machine.

293
00:24:34,940 --> 00:24:41,309
Yes, a PCM adapter would let you make an essentially
identical copy of whatever it is you record with it -

294
00:24:41,309 --> 00:24:44,027
and that is mighty impressive.

295
00:24:44,027 --> 00:24:47,999
But using one is extremely clunky and tedious.

296
00:24:47,999 --> 00:24:51,099
It requires having a very-expensive VCR,

297
00:24:51,099 --> 00:24:54,644
hooking that into your HiFi
(so I hope you put your TV over there, too),

298
00:24:54,644 --> 00:24:58,116
and wrangling two machines at the same time.

299
00:24:58,116 --> 00:25:01,943
That’s a lot of effort to go through for a simple sound recording,

300
00:25:01,943 --> 00:25:06,776
though in fairness you don’t really interact with the adapter
all that much.

301
00:25:06,776 --> 00:25:12,108
Now, if you could perhaps bring your exotic PCM videocassette recordings to a friend

302
00:25:12,108 --> 00:25:17,801
who had also spent as much as a small car on a
videocassette recorder and PCM adapter,

303
00:25:17,801 --> 00:25:20,762
then maybe there’s some more value here.

304
00:25:20,762 --> 00:25:23,733
But that leads us to a minor mystery:

305
00:25:23,733 --> 00:25:28,485
was this ever, like, a real format?

306
00:25:28,485 --> 00:25:35,742
Could I expect a tape holding data the way this fella writes it
to be readable by a different PCM adapter?

307
00:25:35,742 --> 00:25:38,387
Signs point to maybe.

308
00:25:38,387 --> 00:25:42,570
I found a forum post where jamesp, a serious tapehead,

309
00:25:42,570 --> 00:25:51,511
claims that 16 bit tapes are compatible between a bunch of different adapter models,
so at least Sony had some sort of standard format.

310
00:25:51,511 --> 00:25:53,895
But what about 14 bit tapes?

311
00:25:53,895 --> 00:25:56,683
If you know a thing or none about digital sound,

312
00:25:56,683 --> 00:26:04,172
it might seem a little strange that this device allows you to choose
whether you want to record with 14 or 16 bit sample depth.

313
00:26:04,172 --> 00:26:09,952
An option for “slightly worse recordings”
seems pretty silly in isolation.

314
00:26:09,952 --> 00:26:15,896
But it’s less silly when you consider that
Sony’s first PCM-1 was a 14-bit model.

315
00:26:15,896 --> 00:26:23,759
And, supposedly, that model followed an encoding standard
that the Electronic Industries Association of Japan had come up with.

316
00:26:23,759 --> 00:26:30,534
There’s definitely evidence that that was a thing,
and here’s a JVC product that utilized that standard.

317
00:26:30,534 --> 00:26:36,474
For some more evidence, not that long ago
Techmoan covered the Technics SV-P100,

318
00:26:36,474 --> 00:26:39,970
a digital recording device from 1981.

319
00:26:39,970 --> 00:26:46,150
That thing was essentially just a 14-bit PCM adapter
with a nicely-integrated VHS VCR,

320
00:26:46,150 --> 00:26:53,419
and the video it pumps out through its "digital" output
sure looks an awful lot like the video this thing is generating.

321
00:26:53,419 --> 00:27:00,209
I think there’s a pretty good chance that a 14-bit recording
made with this Sony PCM adapter and a VHS VCR

322
00:27:00,209 --> 00:27:03,894
would work in that machine, and vice-versa.

323
00:27:03,894 --> 00:27:08,247
I’m hoping to arrange a test… so stay tuned.

324
00:27:08,247 --> 00:27:18,385
Merely offering the option to make 14 bit recordings implies to me anyway that they must be backward-compatible with some array of older equipment.

325
00:27:18,385 --> 00:27:22,191
There’s no way to get the raw data out of this model -

326
00:27:22,191 --> 00:27:27,291
the copy output just produces another video signal to feed a second VCR.

327
00:27:27,291 --> 00:27:34,194
So I can’t think of any other reason it would offer a slightly worse recording mode.

328
00:27:34,194 --> 00:27:35,544
But curiously,

329
00:27:35,544 --> 00:27:42,059
the pattern on the screen doesn’t really change much
when you move between 14 and 16 bit encoding.

330
00:27:42,059 --> 00:27:48,496
I figured it would - less bits per sample would mean
less bits per line so they should appear to get bigger.

331
00:27:48,496 --> 00:27:54,057
But they don’t, it’s just the portion at the end of each line gets rearranged a bit.

332
00:27:54,057 --> 00:27:59,396
My guess is that Sony altered the error correction portion to fit in the extra bits,

333
00:27:59,396 --> 00:28:01,210
but that’s just a guess.

334
00:28:01,210 --> 00:28:05,517
If they did, perhaps the 14-bit mode is less prone to errors

335
00:28:05,517 --> 00:28:10,935
but I gotta say from the tests I’ve done
the 16-bit mode is mighty resilient.

336
00:28:10,935 --> 00:28:14,475
Anyway, even assuming there was a standard recording method

337
00:28:14,475 --> 00:28:21,528
and you could expect PCM recordings made on one rich audiophile’s VCR
to work at another rich audiophile’s house,

338
00:28:21,528 --> 00:28:25,786
there still seems to be very little reason to own one of these

339
00:28:25,786 --> 00:28:27,789
beyond bragging rights.

340
00:28:27,789 --> 00:28:30,764
At its core, this is just a really expensive,

341
00:28:30,764 --> 00:28:31,974
really tedious,

342
00:28:31,974 --> 00:28:33,412
and really exotic...

343
00:28:33,412 --> 00:28:37,301
tape deck designed to work with your average hi-fi system.

344
00:28:37,301 --> 00:28:43,389
If you actually had your own recording studio
and could truly take advantage of this thing’s capabilities,

345
00:28:43,389 --> 00:28:48,137
you’d probably be quite annoyed that it doesn’t have XLR inputs.

346
00:28:48,137 --> 00:28:53,412
This is just far too basic to work as a professional piece of recording equipment,

347
00:28:53,412 --> 00:29:00,951
and without music getting released on PCM videotape,
you’re only ever gonna be listening to your own recordings.

348
00:29:00,951 --> 00:29:04,443
So… why go to this extreme?

349
00:29:04,443 --> 00:29:08,274
There is, however, one concrete advantage to this thing:

350
00:29:08,274 --> 00:29:09,947
recording time.

351
00:29:09,947 --> 00:29:17,239
So long as your VCR is halfway decent,
you could use its slower recording speeds with the PCM adapter.

352
00:29:17,239 --> 00:29:23,922
That meant you could get a 4 and a half hour recording out of 
*this thing* and an L-750 Beta cassette,

353
00:29:23,922 --> 00:29:28,118
and potentially an 8 hour recording with a VHS machine.

354
00:29:28,118 --> 00:29:33,836
That bests pretty much every sound recording format that used physical media,

355
00:29:33,836 --> 00:29:38,989
especially when you consider that the audio quality
would be essentially perfect.

356
00:29:38,989 --> 00:29:42,556
So you could fit a whole lot of…

357
00:29:42,556 --> 00:29:47,219
borrowed music on there and make quite the mixtape.

358
00:29:47,219 --> 00:29:51,168
But unless you had that specific use in mind,

359
00:29:51,168 --> 00:29:56,089
this still reads to me as an item of very questionable usefulness.

360
00:29:56,089 --> 00:30:03,707
Despite the peculiarity of a home PCM-adapters,
professional PCM-adapters would stick around for a while.

361
00:30:03,707 --> 00:30:09,456
There still wasn’t a great way to store
several hundred megabytes of data in 1982.

362
00:30:09,456 --> 00:30:15,779
While we had the compact disc,
recordable compact discs wouldn’t appear until the end of the 1980s.

363
00:30:15,779 --> 00:30:24,454
Commercially-produced CDs were pressed,
and after all something had to store data to bring to the CD-making machines.

364
00:30:24,454 --> 00:30:29,066
That something was largely U-matic tapes and the PCM adapters

365
00:30:29,066 --> 00:30:34,907
until Sony finally released an actually-digital tape format in 1987 called, fittingly,

366
00:30:34,907 --> 00:30:36,714
digital audio tape.

367
00:30:36,714 --> 00:30:44,278
As a curious side-note, Sony intended for that format to supplant the venerable compact cassette in the consumer space,

368
00:30:44,278 --> 00:30:47,305
but it was too expensive to really get off the ground.

369
00:30:47,305 --> 00:30:53,884
Plus, it freaked out the recording industry because suddenly people could have perfect copies of their buddy’s CDs

370
00:30:53,884 --> 00:30:56,742
and there was a whole kerfuffle about that.

371
00:30:56,742 --> 00:31:01,664
It’s not surprising that they never bothered
getting hot and bothered by PCM adapters because

372
00:31:01,664 --> 00:31:05,676
these were just too clunky to use and would never see mass-market appeal.

373
00:31:05,676 --> 00:31:12,261
Finally, since you could get 8 hours of CD-quality
audio running on a VHS tape with this thing,

374
00:31:12,261 --> 00:31:15,886
you might be wondering how much actual data that is.

375
00:31:15,886 --> 00:31:20,836
Well, the simple way to calculate that is
to take the 480 minutes in 8 hours,

376
00:31:20,836 --> 00:31:24,617
divide that by the 80 minutes a standard CD-R can hold,

377
00:31:24,617 --> 00:31:29,311
and multiply that by the 700 megabytes each of those CD-Rs can hold.

378
00:31:29,311 --> 00:31:31,739
That would be 4.2 gigabytes.

379
00:31:31,739 --> 00:31:37,582
However, CD-digital audio actually conveys more data than a CD-ROM does.

380
00:31:37,582 --> 00:31:39,304
To be absolutely precise,

381
00:31:39,304 --> 00:31:44,913
this thing records two 16 bit samples 44,056 times per second.

382
00:31:44,913 --> 00:31:49,207
That’s 1,409,792 bits per second.

383
00:31:49,207 --> 00:31:50,742
Multiply by seconds per minute,

384
00:31:50,742 --> 00:31:51,559
minutes per hour,

385
00:31:51,559 --> 00:31:52,579
hours per tape,

386
00:31:52,579 --> 00:31:55,761
then divide by 8 to find the total number of bytes.

387
00:31:55,761 --> 00:31:59,956
After the amusement of realizing you just multiplied by 8 and then divided by 8,

388
00:31:59,956 --> 00:32:09,305
you’ll discover that a T-160 VHS tape holds a bit over
5 gigabytes of data when storing PCM audio at the SLP speed.

389
00:32:09,305 --> 00:32:10,878
And to finish up the video,

390
00:32:10,878 --> 00:32:15,430
one thing that’s always been pretty amusing to me is that, in hindsight,

391
00:32:15,430 --> 00:32:22,248
it seems it took a long time for people to realize that digital audio data was, in fact,

392
00:32:22,248 --> 00:32:23,418
data.

393
00:32:23,418 --> 00:32:28,623
Like, it took us years to turn the compact disc into the CD-ROM -

394
00:32:28,995 --> 00:32:35,998
some of that was down to 8-bit home computers having 
absolutely no idea what to do with 650 megabytes,

395
00:32:35,998 --> 00:32:46,792
but when you consider that Sony sold a device back in 1977 that could reliably store literal gigabytes of data on Beta tapes of all things…

396
00:32:46,792 --> 00:32:51,762
well you’d think people would have made
use of that for more than just audio.

397
00:32:51,850 --> 00:32:54,419
Of course, eventually we did.

398
00:32:54,419 --> 00:33:02,410
LGR covered a device from 1996 that was designed
to make actual data backups onto VHS tapes.

399
00:33:02,410 --> 00:33:05,046
That thing was effectively a PCM adapter,

400
00:33:05,046 --> 00:33:09,919
but one that interfaced with data backup software running on your PC.

401
00:33:09,919 --> 00:33:12,762
To attain the reliability needed for data backups,

402
00:33:12,762 --> 00:33:20,834
it recorded less densely than this PCM adapter did, and could only backup about
3 gigabytes of data in the best of conditions.

403
00:33:20,834 --> 00:33:28,061
But honestly, it’s pretty wild to me that it took until the mid-nineties
for anyone to commercialize that concept.

404
00:33:28,061 --> 00:33:33,059
I mean, did everyone just forget about PCM adapters?

405
00:33:33,059 --> 00:33:39,190
Or did people never realize that the digital audio data they barf out
is still data?

406
00:33:39,748 --> 00:33:45,043
Yeah, using a VHS-based computer backup system
was incredibly clunky -

407
00:33:45,043 --> 00:33:50,674
even worse than a PCM adapter as now you have to deal with a
computer and software interface.

408
00:33:50,674 --> 00:33:57,360
But we had been recording gigabytes of data onto videotape from the 70’s.

409
00:33:57,360 --> 00:34:00,929
How did that not bleed into home computing sooner?

410
00:34:00,929 --> 00:34:03,075
I think the likely answer is, of course,

411
00:34:03,075 --> 00:34:10,785
that it took many years for us to need such vast quantities of data
for anything other than audio reproduction.

412
00:34:10,785 --> 00:34:15,552
Until the multimedia PC was a thing, 
you were mainly dealing with floppy disks,

413
00:34:15,552 --> 00:34:21,418
and one hundred-megabyte hard drives still felt pretty cutting-edge in 1990.

414
00:34:21,418 --> 00:34:28,275
Needing to burn through 1.4 megabits of data every second 
remained an audio-only task

415
00:34:28,275 --> 00:34:33,705
pretty much right up until home computers started incorporating CD-ROM drives.

416
00:34:33,705 --> 00:34:42,530
And at that point we were still struggling to figure out how
on Earth to make use of their vast 650 million bytes!

417
00:34:42,530 --> 00:34:46,220
But now, I think I’ve finally run out of things to talk about.

418
00:34:46,220 --> 00:34:53,056
Though I still think having a PCM adapter in your home
was a pretty silly proposition for the vast majority of people,

419
00:34:53,056 --> 00:34:56,083
they were without question very cool -

420
00:34:56,083 --> 00:35:02,314
and I’m happy they did make it to the consumer market because without audiophiles with too much money to throw around,

421
00:35:02,314 --> 00:35:05,039
I doubt I’d have been able to show you one.

422
00:35:05,039 --> 00:35:13,802
Although, as it turns out, apparently digital sound was quite the contentious topic among audiophiles back in the early eighties.

423
00:35:13,802 --> 00:35:15,700
Because of course it was.

424
00:35:15,700 --> 00:35:20,434
Oh, audiophiles, never stop being you…

425
00:35:21,240 --> 00:35:23,917
♫ 16-bit smooth jazz ♫

426
00:35:25,134 --> 00:35:26,779
Keep recording, okay?

427
00:35:26,779 --> 00:35:28,760
I want you to keep recording.

428
00:35:29,101 --> 00:35:31,060
♫ DON’T STOP ♫

429
00:35:31,060 --> 00:35:32,220
♫ RECORDING. ♫

430
00:35:32,220 --> 00:35:38,084
Discreeeeeet bloooooocky shaaaapes come and goooo.

431
00:35:38,084 --> 00:35:39,667
And if the spicy snap of s…

432
00:35:39,667 --> 00:35:43,731
yeah, heh, I forgot how slowly I’m gonna read that!

433
00:35:44,475 --> 00:35:46,209
It will spit out a binary

434
00:35:46,209 --> 00:35:47,895
[burps]
[laughs]

435
00:35:48,609 --> 00:35:54,875
So, 44.1 kilohertz became the defacto standard for PCM adapters and wwww that…

436
00:35:54,875 --> 00:35:56,381
ah, fark!

437
00:35:56,908 --> 00:36:00,994
And it did pretty much exactly what this thing does,
just five years earlier.

438
00:36:00,994 --> 00:36:02,670
... sanity check processing ...

439
00:36:02,670 --> 00:36:05,259
Six - it’s six years earlier! I did…

440
00:36:06,283 --> 00:36:08,018
Of course, I had [bonk] to…

441
00:36:08,018 --> 00:36:09,059
well, that didn’t work.

442
00:36:11,356 --> 00:36:13,153
OK, two things:

443
00:36:13,153 --> 00:36:16,084
First. I forgot to fade the music back up here.

444
00:36:16,084 --> 00:36:17,344
A tragic oversight.

445
00:36:17,344 --> 00:36:19,976
Everybody loves this song and to dooty doots here.

446
00:36:19,976 --> 00:36:22,719
Second,

447
00:36:22,719 --> 00:36:24,140
actually I don't have a second thing.

448
00:36:24,140 --> 00:36:25,973
Just wanted to say something about that editing mistake.

449
00:36:25,973 --> 00:36:26,473
'kay bye