1
00:00:00,080 --> 00:00:01,080
Lasers!

2
00:00:01,080 --> 00:00:02,080
Rainbows!

3
00:00:02,080 --> 00:00:02,960
The eighties!

4
00:00:02,960 --> 00:00:03,840
Drum Machines!

5
00:00:03,840 --> 00:00:04,560
Digital!

6
00:00:04,560 --> 00:00:05,560
Big hair!

7
00:00:05,760 --> 00:00:07,180
This is some righteous stuff!

8
00:00:07,360 --> 00:00:11,200
No kidding, the compact disc was a radical
departure from how,

9
00:00:11,200 --> 00:00:13,980
well really how a lot of stuff worked.

10
00:00:13,980 --> 00:00:18,920
You could argue that the CD, with its vast
data capacity, relatively robust nature, and

11
00:00:18,920 --> 00:00:23,800
with the further developments it spurred along,
changed how the world did virtually all media.

12
00:00:24,360 --> 00:00:28,880
That is at least until physical media became
the seemingly undesirable thing it is today,

13
00:00:28,880 --> 00:00:33,880
a time when streaming services and libraries
on hard drives are all the rage.

14
00:00:33,880 --> 00:00:36,080
Unless of course it’s vinyl, then by all
means please

15
00:00:36,080 --> 00:00:37,140
build your collections.

16
00:00:37,140 --> 00:00:39,380
Wow the snark’s coming early today.

17
00:00:39,380 --> 00:00:42,480
Well, this is the third video in a series
on digital sound.

18
00:00:42,480 --> 00:00:45,950
You can find a playlist to the previous two
videos, in which we covered how digital sound

19
00:00:45,950 --> 00:00:50,560
works (as well as the Nyquist-Shannon sampling
theorem), but for now, sit back and relax

20
00:00:50,560 --> 00:00:55,070
as you feast your eyes on the silver platter
that is the compact disc.

21
00:00:55,070 --> 00:01:00,100
No discussion of the Compact Disc is a good
discussion unless it pays homage to its predecessor,

22
00:01:00,100 --> 00:01:01,100
the LaserDisc.

23
00:01:01,100 --> 00:01:04,510
Now, I’ve done a series on Laserdisc if
you’d like to learn more, but in brief,

24
00:01:04,510 --> 00:01:07,980
this was the very first commercial optical
storage format.

25
00:01:07,980 --> 00:01:13,680
First released in test markets in 1978, Laserdiscs
were usually 12 inch or 30 centimeter discs,

26
00:01:13,680 --> 00:01:18,180
and they were an analog video format, holding
up to one hour of video per side.

27
00:01:18,180 --> 00:01:22,290
Competing in a world where the videocassette
recorder which could record from live TV already

28
00:01:22,290 --> 00:01:27,030
existed, the Laserdisc failed to capture the
hearts and minds of many individuals even

29
00:01:27,030 --> 00:01:29,090
though it had steller video quality.

30
00:01:29,090 --> 00:01:33,640
Throughout its life, it stayed a videophile-only
format in most markets.

31
00:01:33,640 --> 00:01:37,850
But, the development of the Laserdisc, which
was done in large part by Philips, presented

32
00:01:37,850 --> 00:01:41,800
an obvious solution to the problem of digital
sound storage.

33
00:01:41,800 --> 00:01:45,780
See, although Laserdisc is an analog format,
the signals encoded on it are as a series

34
00:01:45,790 --> 00:01:47,270
of pits and lands.

35
00:01:47,270 --> 00:01:49,770
OK, optical disc fundamentals time!

36
00:01:49,770 --> 00:01:53,670
You might already be aware of this, but optical
discs are read by shining a laser up at a

37
00:01:53,670 --> 00:01:56,780
reflective disc that is covered with little
pits.

38
00:01:56,780 --> 00:02:00,850
These pits are roughly one quarter as deep
as the wavelength of laser light that will

39
00:02:00,850 --> 00:02:01,850
hit them.

40
00:02:01,850 --> 00:02:06,310
I ran into some inconsistencies regarding
the exact depth of the pits, because the only

41
00:02:06,310 --> 00:02:11,120
source I found which specifies it has the
wrong wavelength of light listed for the CD,

42
00:02:11,120 --> 00:02:15,470
but all you need to know is that when the
focused laser hits a pit, the increased depth

43
00:02:15,470 --> 00:02:19,951
causes the reflected light to destructively
interfere with the projected light, which

44
00:02:19,951 --> 00:02:23,130
reduces the overall intensity of the light
reflected back.

45
00:02:23,130 --> 00:02:26,340
That’s actually a pretty neat part that often
gets overlooked.

46
00:02:26,340 --> 00:02:29,870
Endless articles talk about the fact that
the pits change how the light is reflected,

47
00:02:29,870 --> 00:02:33,160
but very few mention the destructive interference
aspect of it.

48
00:02:33,160 --> 00:02:37,400
I’ve shown this diagram before, and it perfectly
demonstrates what happens.

49
00:02:37,400 --> 00:02:41,631
When the laser hits a not-pit, the light gets
reflected right back down to the laser, and

50
00:02:41,631 --> 00:02:44,500
a prism reflects some of this into the photocell.

51
00:02:44,500 --> 00:02:49,030
But when it hits a pit, the destructive interference
greatly reduces the intensity of the reflected

52
00:02:49,030 --> 00:02:52,150
light, so very little light hits the photocell.

53
00:02:52,150 --> 00:02:56,220
This is how a laser pickup system can tell
the difference between a pit and a land.

54
00:02:56,220 --> 00:03:00,730
In the LaserDisc system, these pits and lands
were used to encode analog video and audio

55
00:03:00,730 --> 00:03:05,880
signals via a weird hybrid of pulse-width
modulation and frequency modulation--

56
00:03:05,880 --> 00:03:07,860
Don't ask, it’s complicated

57
00:03:07,860 --> 00:03:12,470
--and the result is
a usable analog video signal from a shiny plastic disc.

58
00:03:12,470 --> 00:03:17,350
So, having already invented a thing that used
lasers to read information on a disc, when

59
00:03:17,350 --> 00:03:21,660
it came time for a digital music format to
hit the scene, Philips was poised to knock

60
00:03:21,660 --> 00:03:27,540
it out of the park with a new disc, this one
no less lasery, but quite a bit more compact.

61
00:03:27,540 --> 00:03:32,810
They named the format along the lines of their
previous compact invention, the compact cassette,

62
00:03:32,810 --> 00:03:37,540
and in a non-coincidence, the diameter of
the CD is roughly the same as the diagonal

63
00:03:37,540 --> 00:03:39,260
length of the Compact Cassette.

64
00:03:39,260 --> 00:03:41,940
Ah, but let’s not forget Sony’s role.

65
00:03:41,940 --> 00:03:46,900
Sony, the people who seem to only make either
runaway successes or disastrous failures,

66
00:03:46,900 --> 00:03:50,020
had been working on digital audio for some
time.

67
00:03:50,020 --> 00:03:54,180
They were the ones that developed a PCM adapter
for use with U-Matic videocassette recorders

68
00:03:54,180 --> 00:03:58,170
as discussed in the previous video, and in
fact they were working on an digital optical

69
00:03:58,170 --> 00:04:01,400
audio disc before Philips released the Laserdisc.

70
00:04:01,400 --> 00:04:06,019
One of their early prototypes from 1977 was
the same size as one of these honkers and

71
00:04:06,019 --> 00:04:11,349
held only an hour of digital audio, though
at the same exact quality of the soon-to-be

72
00:04:11,349 --> 00:04:14,050
Compact Disc-Digital Audio standard.

73
00:04:14,050 --> 00:04:18,259
Philips and Sony were sort of working on the
same thing at the same time, though Philips

74
00:04:18,259 --> 00:04:22,339
had the notable advantage of having already
developed and manufactured the Laserdisc by

75
00:04:22,339 --> 00:04:24,370
the time things really heated up.

76
00:04:24,370 --> 00:04:26,880
Still, Sony contributed a lot.

77
00:04:26,880 --> 00:04:31,639
I don’t want to get too into the weeds of
who did what, so let’s just jump to 1979,

78
00:04:31,639 --> 00:04:36,180
the year that Sony and Philips first decided
to for realsies collaborate on the project.

79
00:04:36,180 --> 00:04:39,610
By this time, optical disc fundamentals had
been established.

80
00:04:39,610 --> 00:04:43,780
An optical disc seemed the perfect format
for digital data, because you could just easily

81
00:04:43,780 --> 00:04:45,620
call a pit a one and a land a zero.

82
00:04:45,620 --> 00:04:47,279
But that’s not how it works!

83
00:04:47,279 --> 00:04:51,599
No, the pits and lands are important, but
it is the change between a pit and a land

84
00:04:51,599 --> 00:04:55,389
that encodes a 1, and no change encodes a
zero.

85
00:04:55,389 --> 00:05:00,120
This is time-based, so a four-bit span of
time which is comprised of either all pits

86
00:05:00,120 --> 00:05:03,710
or all lands will produce 4 zero bits.

87
00:05:03,710 --> 00:05:08,770
Start the sequence with a change and then
continue as is, and you get 1000.

88
00:05:08,770 --> 00:05:13,979
No change, change, no change, no change, and
you get 0100.

89
00:05:13,979 --> 00:05:14,990
And you get the idea.

90
00:05:14,990 --> 00:05:18,319
This is called Non-Return-To-Zero inverted
encoding.

91
00:05:18,319 --> 00:05:23,430
Now, this has limitations because a long span
of zeros requires an outside clock to keep

92
00:05:23,430 --> 00:05:26,699
track of how many “dead” spaces have passed.

93
00:05:26,699 --> 00:05:32,009
The longer you have between ones, or changes,
the more ambiguous the number of zeroes becomes.

94
00:05:32,009 --> 00:05:33,869
I know what you’re thinking.

95
00:05:33,869 --> 00:05:35,699
Was that six zeros or only five?

96
00:05:35,699 --> 00:05:39,919
Well, to tell you the truth in all this excitement
I kinda lost track myself.

97
00:05:39,919 --> 00:05:44,629
Which is why you need an outside timing source
keeping track of how many shots, I mean bits,

98
00:05:44,629 --> 00:05:45,819
have passed.

99
00:05:45,819 --> 00:05:47,750
This isn’t somewhere you should just feel
lucky.

100
00:05:47,750 --> 00:05:48,960
But that’s not a problem.

101
00:05:48,960 --> 00:05:51,879
What is a problem is the nature of everything.

102
00:05:51,879 --> 00:05:57,210
How likely do you think it is that a pressed
CD is absolutely perfect, has no scratches

103
00:05:57,210 --> 00:06:02,270
at all, and that the CD player reading the
disc will perfectly, without any errors, reproduce

104
00:06:02,270 --> 00:06:05,229
the correct sequence of ones and zeros?

105
00:06:05,229 --> 00:06:08,069
If you answered “not likely at all” you’re
a winner!

106
00:06:08,069 --> 00:06:12,309
To help make the data less susceptible to
stupid little things, two robust error-fighting

107
00:06:12,309 --> 00:06:14,719
mechanisms are built into the data stream.

108
00:06:14,719 --> 00:06:18,960
The Red-Book standard, the first of the Rainbow
Books that defines the physical, digital,

109
00:06:18,960 --> 00:06:23,949
and other various standards surrounding each
type of Compact Disc, not only specifies the

110
00:06:23,949 --> 00:06:28,639
sample rate and bit depth of the Compact Disc
Digital Audio format, which as previously

111
00:06:28,640 --> 00:06:35,760
discussed is 44.1 kilohertz, 16 bit, but it
also defines how the data is encoded on the disc.

112
00:06:35,760 --> 00:06:39,559
Now this is rather technical but I think interesting,
so bear with me.

113
00:06:39,559 --> 00:06:44,160
So, each audio sample is a signed, which means
it can be positive or negative,

114
00:06:44,160 --> 00:06:46,240
16 bit two’s complement,

115
00:06:46,240 --> 00:06:50,580
which is a mathematical operation on binary numbers that we’re just gonna not worry about right now because it hurts my brain,

116
00:06:50,580 --> 00:06:51,700
integer.

117
00:06:51,700 --> 00:06:55,639
I mean, we knew we’re dealing with 16 bit
audio so each sample is gonna be 16 bits.

118
00:06:55,639 --> 00:07:00,439
Now, on the disc, 12 samples, 6 each for the
left and right channels, are stored together

119
00:07:00,439 --> 00:07:06,259
in a frame of 192 bits (that’s 24 bytes,
for those playing along at home).

120
00:07:06,259 --> 00:07:10,589
These frames are then encoded using an error
correction scheme called CIRC, which stands

121
00:07:10,589 --> 00:07:13,509
for Cross-interleaved Reed-Solomon coding.

122
00:07:13,509 --> 00:07:18,129
In addition to adding one data parity byte
to every three raw data bytes, the effect

123
00:07:18,129 --> 00:07:21,990
of CIRC is basically to spread the data out
over a longer distance.

124
00:07:21,990 --> 00:07:24,979
That’s where the interleaving part of the
name comes from.

125
00:07:24,979 --> 00:07:30,520
By jumbling up multiple frames and adding
parity bytes, CIRC can correct up to 3,500

126
00:07:30,520 --> 00:07:35,890
bits of error-filled or even missing data,
and can compensate for up to 12,000 bits by

127
00:07:35,890 --> 00:07:38,800
masking errors via interpolation.

128
00:07:38,800 --> 00:07:44,199
This translates to up to 2.4mm gaps in data
being completely corrected for, and up to

129
00:07:44,199 --> 00:07:49,330
an 8.5mm scrambling of data, either through
a scratch or some other damage, being reasonably

130
00:07:49,330 --> 00:07:51,409
interpolated and masked.

131
00:07:51,409 --> 00:07:54,347
The end result is that the error is either
completely corrected,

132
00:07:54,347 --> 00:07:57,330
or it’s fudged well enough that you won’t hear it.

133
00:07:57,330 --> 00:07:59,280
Now we’re gonna go on a minor tangent here.

134
00:07:59,280 --> 00:08:00,280
I apologize.

135
00:08:00,320 --> 00:08:05,020
I’ve linked in the description the source
material from the Wikipedia article on CIRC.

136
00:08:05,039 --> 00:08:09,339
This source material is from a book written
by Kees Schouhamer Immink, one of the central

137
00:08:09,339 --> 00:08:12,520
engineers involved in the development of the
Compact Disc.

138
00:08:12,520 --> 00:08:17,090
He even won an Emmy for his work on coding
technology for optical recording formats.

139
00:08:17,090 --> 00:08:21,379
I’m bringing this up because for every person
that tells you Wikipedia is a worthless starting

140
00:08:21,379 --> 00:08:26,839
point for research, I want you to show them
the references section at the bottom of articles.

141
00:08:26,839 --> 00:08:32,610
Yes, you would be very unwise to cite “Wikipedia”
in any research, but let me tell you,

142
00:08:32,610 --> 00:08:37,130
you may be amazed at the quality of the source
material, and you’d be a fool to not at

143
00:08:37,130 --> 00:08:41,780
least look at these references when doing
any preliminary research of your own.

144
00:08:41,780 --> 00:08:42,700
Rant over.

145
00:08:42,700 --> 00:08:47,400
In addition to CIRC, the use of eight-to-fourteen
modulation limits the total number of possible

146
00:08:47,400 --> 00:08:50,150
combinations of ones and zeros.

147
00:08:50,150 --> 00:08:54,510
EFM translates each 8 bit word into a 14 bit
word.

148
00:08:54,510 --> 00:08:59,750
These 14 bit words are translated back into
their original 8 bit words using a lookup table.

149
00:08:59,750 --> 00:09:03,030
The point of doing this is to reduce the possibility
of errors.

150
00:09:03,030 --> 00:09:08,610
The use of EFM makes it such that binary ones
are always separated by at least two zeros,

151
00:09:08,610 --> 00:09:10,840
and a maximum of 10 zeros.

152
00:09:10,840 --> 00:09:14,780
This means that every pit and land is at least
3 clock cycles long.

153
00:09:14,780 --> 00:09:19,070
It also means that if the CD player reads
one, zero, one, it knows it must have made

154
00:09:19,070 --> 00:09:21,560
an error because that’s not a possible sequence.

155
00:09:21,560 --> 00:09:26,260
Plus, with a maximum of 10 zeroes, it reduces
the accuracy required in the clock of the

156
00:09:26,260 --> 00:09:32,110
CD player for worst-case clock recovery, as
there must be a one after every eleventh bit,

157
00:09:32,110 --> 00:09:35,850
and this will in effect synchronize and restart
the zero-counting clock.

158
00:09:35,850 --> 00:09:41,110
Keep in mind that with simple 8 bit encoding,
in theory you could have 14 zeros in a row.

159
00:09:41,110 --> 00:09:44,830
When you realize all of the processing that
has to be done by the CD player before it

160
00:09:44,830 --> 00:09:49,140
can even extract the data it needs to send
to the DAC and play the dang music, you gain

161
00:09:49,140 --> 00:09:52,070
a newfound respect for its achievements of
the time.

162
00:09:52,070 --> 00:09:56,780
Granted, using a look-up table and performing
some basic arithmetic is easy for a computer,

163
00:09:56,780 --> 00:10:01,320
but the fact that this was being done at a
consumer hardware level in 1982, with a data

164
00:10:01,320 --> 00:10:05,450
throughput faster than what any contemporary
microcomputer would reasonably be expected

165
00:10:05,450 --> 00:10:07,700
to process, impresses me.

166
00:10:07,700 --> 00:10:12,290
To help provide logical access to the contents
of the disc, the disc’s data stream is divided

167
00:10:12,290 --> 00:10:13,560
into three parts.

168
00:10:13,560 --> 00:10:16,760
The lead-in, the program area, and lead-out.

169
00:10:16,760 --> 00:10:20,160
The lead-in contains the disc’s Table of
Contents, which is basically an announcement

170
00:10:20,160 --> 00:10:24,090
to the player of how long it is, how many
tracks it contains, and what the timecode

171
00:10:24,090 --> 00:10:25,980
is for each of the tracks.

172
00:10:25,980 --> 00:10:30,280
The CD player can, through reading the table
of contents, determine where each track is

173
00:10:30,280 --> 00:10:32,700
for accessing it nearly instantly.

174
00:10:32,700 --> 00:10:38,851
A CD can have up to 99 tracks, which themselves
can be divided further into 100 indexes, though

175
00:10:38,851 --> 00:10:43,920
this feature was rarely ever used and few
CD players could access the index information.

176
00:10:43,920 --> 00:10:48,030
One thing that computers have made a little
confusing about the Compact Disc-Digital Audio

177
00:10:48,030 --> 00:10:52,790
standard is that audio CDs do not contain
files.

178
00:10:52,790 --> 00:10:56,720
If you pop one into a PC, it’s gonna show
you each track as its own object.

179
00:10:56,720 --> 00:10:59,810
But the computer is interpreting that for
you.

180
00:10:59,810 --> 00:11:04,690
In raw form, the data on a CD is just one
continuous stream, and the table-of-contents

181
00:11:04,690 --> 00:11:09,770
in the lead-in simply defines where along
the stream each track is.

182
00:11:09,770 --> 00:11:13,180
The concept of using a CD for computer data
storage

183
00:11:13,180 --> 00:11:15,180
just wasn’t really in the cards yet.

184
00:11:15,180 --> 00:11:20,100
I mean, a single audio track would easily
fill up entire hard drives of the time, so

185
00:11:20,100 --> 00:11:25,110
the idea of creating files to contain the
audio data was just absurd.

186
00:11:25,110 --> 00:11:29,400
The later CD-ROM, following the Yellow-book
standard, would allow for file structures

187
00:11:29,400 --> 00:11:31,990
on discs like a computer is used to accessing.

188
00:11:31,990 --> 00:11:33,170
But we’ll get to that later.

189
00:11:33,170 --> 00:11:36,160
OK, so let’s look a little bit closer at
the disc itself.

190
00:11:36,160 --> 00:11:40,960
First, I want you to see if you can spot a
big difference between a Laserdisc and a CD.

191
00:11:40,970 --> 00:11:44,890
Looking at the edge of a Laserdisc, can you
see that seam in the middle?

192
00:11:44,890 --> 00:11:48,700
Laserdiscs are obviously double sided, so
that seam is the join between the two halves

193
00:11:48,700 --> 00:11:52,490
of the disc, and the data is sandwiched between
two sides.

194
00:11:52,490 --> 00:11:55,320
But if you look at the CD, there is no seam.

195
00:11:55,320 --> 00:11:59,500
One of the weirder things about the CD is
that the data layer is actually at the top

196
00:11:59,500 --> 00:12:01,770
of the disc, just beneath the label.

197
00:12:01,770 --> 00:12:05,240
I’ve linked to a How It’s Made episode
on the Compact Disc that does a pretty good

198
00:12:05,240 --> 00:12:08,810
job of demonstrating how mass-produced discs
are made.

199
00:12:08,810 --> 00:12:12,780
Their manufacture is surprisingly similar
to that of conventional vinyl records, as

200
00:12:12,780 --> 00:12:16,280
they are stamped (or rather molded) from a
master disc.

201
00:12:16,280 --> 00:12:20,080
The video does a great job of showing this
process, but it skips over the actual etching

202
00:12:20,080 --> 00:12:22,480
of the data onto the glass master.

203
00:12:22,480 --> 00:12:26,540
In short, the master is covered in a solution
that will either evaporate or harden when

204
00:12:26,540 --> 00:12:30,420
exposed to laser light, depending on the mastering
process used.

205
00:12:30,420 --> 00:12:35,060
By using the laser to etch pits into the coating,
which is then hardened with a development

206
00:12:35,060 --> 00:12:39,280
process, the glass master is now covered in
bumps that will represent the lands in the

207
00:12:39,280 --> 00:12:40,720
molded discs.

208
00:12:40,720 --> 00:12:45,500
The master disc is metallized to harden these
bumps, and now polycarbonate discs are molded

209
00:12:45,500 --> 00:12:46,500
from it.

210
00:12:46,500 --> 00:12:49,880
And that’s something that I find really
neat about the Compact Disc.

211
00:12:49,880 --> 00:12:54,290
The data in stamped discs is actually in the
plastic itself.

212
00:12:54,290 --> 00:12:58,120
When the disc comes out of the mold, it’s
completely transparent.

213
00:12:58,120 --> 00:13:00,730
But it has all of the data on its surface.

214
00:13:00,730 --> 00:13:05,850
To make the disc readable, it’s then covered
in a thin film of aluminum via a vapor metallization

215
00:13:05,850 --> 00:13:09,600
process, and now the disc could theoretically
be read by a CD player.

216
00:13:09,600 --> 00:13:14,240
But remember, those pits and lands are on
the top of the disc, exposed.

217
00:13:14,240 --> 00:13:17,220
If they could be touched, the data would be
destroyed.

218
00:13:17,220 --> 00:13:21,360
So before the disc can be handled, it needs
a thin coat of varnish to be spread along

219
00:13:21,360 --> 00:13:24,330
the top, and now the data is protected from
damage.

220
00:13:24,330 --> 00:13:28,360
Putting the data layer on the top of the disc
meant that the disc was even more tolerant

221
00:13:28,360 --> 00:13:33,740
of scratches, as these scratches are out of
focus to the laser reading the disc from below.

222
00:13:33,740 --> 00:13:35,560
This was a pretty smart move.

223
00:13:35,560 --> 00:13:40,460
The laser would read through almost the entire
1.2mm thickness of the CD.

224
00:13:40,460 --> 00:13:44,580
As a consequence, double-sided CDs were never
a legitimate thing.

225
00:13:44,580 --> 00:13:49,390
But there were some weird shenanigans tried
with making double sided hybrid discs.

226
00:13:49,390 --> 00:13:53,340
One of these I have somewhere in my collection
but I couldn’t find it because I’m disorganized,

227
00:13:53,340 --> 00:13:54,990
(sorry) is the DualDisc.

228
00:13:54,990 --> 00:13:59,340
“Weird Al” Yankovic’s twelfth studio
album, Straight Outta Lynwood, was released

229
00:13:59,340 --> 00:14:05,130
in 2006 as a DualDisc, with one side being
a fully compliant DVD containing music videos

230
00:14:05,130 --> 00:14:07,960
and other goodies, and the other side being
a…

231
00:14:07,960 --> 00:14:09,520
almost CD.

232
00:14:09,520 --> 00:14:14,860
DualDiscs were .3mm thicker than a standard
CD or DVD, comprising a total thickness of

233
00:14:14,860 --> 00:14:18,590
1.5mm rather than the standard 1.2.

234
00:14:18,590 --> 00:14:23,910
The CD layer was placed .9 mm into the disc,
with the DVD layer .6 into the disc from the

235
00:14:23,910 --> 00:14:26,690
other side, which is correct for a DVD.

236
00:14:26,690 --> 00:14:30,950
But it’s off by at least .2mm according
to the Red Book standard.

237
00:14:30,950 --> 00:14:35,360
Because of this, DualDiscs did not contain
the Compact Disc Digital Audio logo on them

238
00:14:35,360 --> 00:14:37,820
because they technically weren’t CDs.

239
00:14:37,820 --> 00:14:41,940
They featured language saying that they were
intended to work in standard CD players, and

240
00:14:41,940 --> 00:14:46,650
almost certainly they would given the tolerances
a standard CD player is designed to deal with,

241
00:14:46,650 --> 00:14:51,210
but they could not actually be officially
referred to as a Compact Disc.

242
00:14:51,210 --> 00:14:52,920
So there’s some fun trivia for you.

243
00:14:52,920 --> 00:14:55,090
AAAND, that’s where we’ll hit pause.

244
00:14:55,090 --> 00:14:59,220
There’s a lot of neat stuff to uncover about
the CD, even though it’s teetering on the

245
00:14:59,220 --> 00:15:01,300
edge of obsolete and insignificant.

246
00:15:02,220 --> 00:15:03,800
OK, it is pretty much obsolete.

247
00:15:03,800 --> 00:15:08,490
This dime-sized SD card holds more data than
this entire column of CDs.

248
00:15:08,490 --> 00:15:11,550
That’s kinda sad, but also amazing.

249
00:15:11,550 --> 00:15:15,070
In my next video on this subject, we’ll
explore more of the innards of the compact

250
00:15:15,070 --> 00:15:18,500
disc, such as the optical pickups mechanisms
and the rather major difference between how

251
00:15:18,500 --> 00:15:22,230
Philips designed its laser pickup compared
to most others.

252
00:15:22,230 --> 00:15:26,050
If you take a look at the disc tray on this
Magnavox unit, you might get a hint.

253
00:15:26,050 --> 00:15:31,090
Of course we’ll also touch on the other
various uses of the CD, such as CD-ROM, CD-R

254
00:15:31,090 --> 00:15:34,000
and CD-RW, and other stuff.

255
00:15:34,000 --> 00:15:37,100
And then, we’ll relish in the fact that
everything is on the Internet now.

256
00:15:37,100 --> 00:15:38,900
Thanks for watching, I hope you enjoyed the
video!

257
00:15:38,900 --> 00:15:42,320
If this is your first time coming across the
channel and you liked what you saw, please

258
00:15:42,320 --> 00:15:43,990
consider subscribing!

259
00:15:43,990 --> 00:15:47,770
As always, thank you to everyone who supports
this channel on Patreon, especially the fine

260
00:15:47,770 --> 00:15:49,710
folks that have been scrolling up your screen.

261
00:15:49,710 --> 00:15:53,630
If you’re interested in making a contribution
to the channel to help it grow, please check

262
00:15:53,630 --> 00:15:54,840
out my Patreon page.

263
00:15:54,840 --> 00:15:56,600
Thanks for your consideration!

264
00:15:56,600 --> 00:16:00,240
Don’t forget there’s a Technology Connections
subreddit now, so if you’re a redditer you

265
00:16:00,240 --> 00:16:03,940
can go over there and watch me not know how
to use it, and I’m getting better a Twitter

266
00:16:03,940 --> 00:16:07,300
so if that’s something you do, you can follow
me @TechConnectify.

267
00:16:07,300 --> 00:16:08,840
Anyway, that’s it for now.

268
00:16:08,850 --> 00:16:10,180
I’ll see you next time!

269
00:16:10,180 --> 00:16:11,840
Cue obnoxious music!

270
00:16:12,300 --> 00:16:16,900
♫ uncomfortably smooth jazz ♫

271
00:16:17,160 --> 00:16:19,760
This line read better before…

272
00:16:19,760 --> 00:16:22,760
With its vast data capacity, relatively lobrust…

273
00:16:24,360 --> 00:16:25,360
this line.

274
00:16:25,370 --> 00:16:27,610
This line is going to kill me!

275
00:16:27,610 --> 00:16:31,529
When it came time for digital music formats
to hit the scene, Philips was poised to knock

276
00:16:31,529 --> 00:16:33,120
it out of the par--poised?

277
00:16:33,120 --> 00:16:34,300
(stares into camera doubting himself)

278
00:16:34,300 --> 00:16:35,940
No, that’s what I wrote.

279
00:16:37,540 --> 00:16:38,620
That’s what I wrote!

280
00:16:38,620 --> 00:16:40,480
I’m regretting it now…

281
00:16:40,480 --> 00:16:44,990
The Red Book Standard, the first of the rainbow
books that define the physical, dizhidal,

282
00:16:44,990 --> 00:16:47,200
and other… dizhidal dizidal diblelr….

283
00:16:47,820 --> 00:16:48,320
(clears throat)

284
00:16:48,720 --> 00:16:52,800
...reduces the accuracy required in the clock
of the CD player for weush…

285
00:16:55,240 --> 00:16:57,140
[exasperated sigh]

286
00:16:57,140 --> 00:16:59,900
The master disc is metAL….

287
00:17:00,300 --> 00:17:01,800
Metalized.