1 00:00:00,070 --> 00:00:05,080 It’s 2017, and because I’m such a dedicated techy committed to having the newest technology 2 00:00:05,080 --> 00:00:10,380 at my fingertips, I just got back from the store with a fascinating piece of technology. 3 00:00:10,380 --> 00:00:11,870 This video cassette recorder. 4 00:00:11,870 --> 00:00:16,160 You probably think of the VCR as an uninteresting, outdated piece of tech. 5 00:00:16,160 --> 00:00:19,540 But there’s some surprisingly interesting stuff inside here. 6 00:00:19,540 --> 00:00:23,759 The VCR contains a device the solved what seemed to be an unsolvable problem. 7 00:00:23,759 --> 00:00:25,130 Let’s have a look. 8 00:00:25,130 --> 00:00:29,390 In the days of analog television, the actual signal that made up the images to be put on 9 00:00:29,390 --> 00:00:33,989 the screen wasn’t a set of instructions on how to build an image using pixels. 10 00:00:33,989 --> 00:00:38,700 It was a complicated, high frequency signal of continually varying intensity that contained 11 00:00:38,700 --> 00:00:42,949 rudimentary triggers to help a television build a coherent image based upon the signal’s 12 00:00:42,949 --> 00:00:46,710 instantaneous strength which corresponded to image brightness at a particular point 13 00:00:46,710 --> 00:00:47,710 on the screen. 14 00:00:47,710 --> 00:00:51,690 Anyway, an analog video signal is an insanely high frequency. 15 00:00:51,710 --> 00:00:55,450 OK, it’s actually not that high by today’s standards, but bear with me. 16 00:00:55,450 --> 00:01:00,309 The 5 megahertz signal of analogue television made for a perfectly acceptable picture, and 17 00:01:00,309 --> 00:01:02,789 there weren’t any problems when it came to everyday use. 18 00:01:02,789 --> 00:01:07,710 Except, that super high frequency meant that recording the video signal was impossible. 19 00:01:07,710 --> 00:01:09,570 Let me explain. 20 00:01:09,570 --> 00:01:13,510 Magnetic tape recording, already in use for recording audio signals from microphones, 21 00:01:13,510 --> 00:01:17,640 has its frequency response, that is how high of a frequency it could reproduce, limited 22 00:01:17,640 --> 00:01:19,220 by its speed. 23 00:01:19,220 --> 00:01:23,190 Due to the structure of the tape itself, to record a high frequency signal it has to be 24 00:01:23,190 --> 00:01:25,939 moving past the tape heads pretty fast. 25 00:01:25,939 --> 00:01:29,360 This isn’t a problem for audio signals, as the highest frequency it needs to produce 26 00:01:29,360 --> 00:01:32,020 is about 20 thousand hertz, or 20 kilohertz. 27 00:01:32,020 --> 00:01:35,890 A speed of 7.5 inches per second is plenty for this purpose. 28 00:01:35,890 --> 00:01:40,700 But video signals are about 5 megahertz, that’s 5 million hertz, much too high a signal to 29 00:01:40,700 --> 00:01:42,590 put on normal tape. 30 00:01:42,590 --> 00:01:46,130 Because of this limitation, TV shows tended to be live and not pre-recorded. 31 00:01:46,130 --> 00:01:50,520 If a show was to be recorded before being broadcast, it was usually filmed with a conventional 32 00:01:50,520 --> 00:01:54,500 motion picture camera, and then a device called a telecine would be used. 33 00:01:54,500 --> 00:01:58,930 A telecine is a machine that can convert motion picture film into a television signal. 34 00:01:58,930 --> 00:02:02,840 Aside from the necessary frame-rate conversion that was accomplished by the machine, you 35 00:02:02,840 --> 00:02:07,040 can think of it as a glorified television camera pointing at a movie screen. 36 00:02:07,040 --> 00:02:10,490 You could also use a kinescope, which was basically the opposite, like pointing a film 37 00:02:10,490 --> 00:02:14,970 camera at a TV screen, the upshot of which was that frame-rate conversion wasn’t necessary 38 00:02:14,970 --> 00:02:18,240 when playing it back due to an already matched framerate. 39 00:02:18,240 --> 00:02:21,940 But using film wasn’t easy, and most importantly it wasn’t cheap. 40 00:02:21,940 --> 00:02:25,920 It would be super convenient to put video signals right onto magnetic tape which was 41 00:02:25,920 --> 00:02:31,090 cheaper and easier to use, not requiring film processing and also being reusable.. 42 00:02:31,090 --> 00:02:33,260 But again, speed was a problem. 43 00:02:33,260 --> 00:02:36,810 In order to record video signals onto this tape, it would have to be traveling at many 44 00:02:36,810 --> 00:02:38,470 feet per second. 45 00:02:38,470 --> 00:02:42,010 With this 1,200 foot spool of tape, you could expect a recording time of about 46 00:02:42,010 --> 00:02:43,630 72 seconds. 47 00:02:43,630 --> 00:02:47,400 It would look a lot like this during normal operation: 48 00:02:47,400 --> 00:02:49,120 But that didn’t stop progress. 49 00:02:49,120 --> 00:02:53,620 At first, attempts were made to just make a really-fast tape recorder. 50 00:02:53,620 --> 00:02:59,340 One such system, the Vision Electronic Recording Apparatus, or Vera, was developed in 1952 51 00:02:59,340 --> 00:03:05,300 by the BBC, the project being led by (now here’s an awesome name) Dr. Peter Axon. 52 00:03:05,300 --> 00:03:09,830 The VERA used massive 20 inch reels that contained 15 THOUSAND feet of tape. 53 00:03:09,830 --> 00:03:12,950 That’s nearly 3 miles of continuous tape. 54 00:03:12,950 --> 00:03:14,040 Yikes. 55 00:03:14,040 --> 00:03:17,261 Even with that vast amount of tape, though, the recording time was only 15 minutes because 56 00:03:17,261 --> 00:03:22,010 the tape traveled at 16.7 feet per second, or over 11 miles an hour. 57 00:03:22,010 --> 00:03:25,970 If it wasn’t obvious that this was impractical, it should’ve been. 58 00:03:25,970 --> 00:03:30,330 Other oddities exist in the linear-video-tape world, such as Toshiba’s LVR system that 59 00:03:30,330 --> 00:03:34,460 used a loop of tape that moved very fast and a head that slowly moved along the tape from 60 00:03:34,460 --> 00:03:38,880 top to bottom essentially making a spiral, but for the most part the idea was abandoned 61 00:03:38,880 --> 00:03:42,060 because, let’s face it, this is just silly. 62 00:03:42,060 --> 00:03:45,640 So what could be done to practically record video onto magnetic tape? 63 00:03:45,640 --> 00:03:49,230 There’s no getting around the fact that the tape has to travel past the heads at at 64 00:03:49,230 --> 00:03:52,950 least a dozen feet per second or so to get a reasonable picture. 65 00:03:52,950 --> 00:03:57,400 To solve this problem, the American company Ampex, based in California, asked a brilliant 66 00:03:57,400 --> 00:04:01,540 question: Why not have the heads move past the tape? 67 00:04:01,540 --> 00:04:07,520 Ampex’s quadruplex system used a rotating drum containing four tape heads that sat perpendicular 68 00:04:07,520 --> 00:04:10,900 to the traveling path of 2 inch wide magnetic tape. 69 00:04:10,900 --> 00:04:14,840 The drum, rather than the tape, is what moved at a high speed. 70 00:04:14,840 --> 00:04:19,110 Spinning at a rate of 3,600 rpm, the heads traveled past the tape very very fast, but 71 00:04:19,110 --> 00:04:22,380 the tape only moved at a speed of 15 inches per second. 72 00:04:22,380 --> 00:04:26,550 By slicing up the width of the tape into small parts of the video signal, the surface of 73 00:04:26,550 --> 00:04:29,530 the tape could be used much more efficiently. 74 00:04:29,530 --> 00:04:33,740 Electronics switched the output between the 4 heads allowing for a seamless video signal. 75 00:04:33,740 --> 00:04:37,460 The Ampex machine was a hit, and it quickly became the standard format for television 76 00:04:37,460 --> 00:04:39,230 studios nationwide. 77 00:04:39,230 --> 00:04:44,520 But these machines were insanely expensive, with the 1956 price being 45,000 dollars, 78 00:04:44,520 --> 00:04:47,130 equivalent to almost four hundred thousand dollars today. 79 00:04:47,130 --> 00:04:50,240 Aside from costing more than a house, they were also huge, about the size of a large 80 00:04:50,240 --> 00:04:54,780 chest freezer not including their many electronic components mounted on racks. 81 00:04:54,780 --> 00:05:00,250 Not to mention, they were obviously very heavy, along with being decidedly not easy to use, 82 00:05:00,250 --> 00:05:02,420 requiring training to operate them. 83 00:05:02,420 --> 00:05:07,210 Fast forward to the mid 1970’s, and consumer video tape recorders are starting to appear. 84 00:05:07,210 --> 00:05:11,950 Betamax and VHS were the two most common formats, with VHS eventually winning the drawn out 85 00:05:11,950 --> 00:05:12,950 format war. 86 00:05:12,950 --> 00:05:17,210 Both of these formats use similar technology to the original quadruplex system, so let’s 87 00:05:17,210 --> 00:05:19,330 have a look at what’s on the inside. 88 00:05:19,330 --> 00:05:22,910 This is a run-of-the-mill VHS cassette recorder from the early eighties. 89 00:05:22,910 --> 00:05:26,920 All VCRs contain a video head system similar to the quadruplex system. 90 00:05:26,920 --> 00:05:28,310 That's it there. 91 00:05:28,310 --> 00:05:32,170 But before we get too involved in that, let's have a look at the cassette itself. 92 00:05:32,170 --> 00:05:36,260 Any cassette tape is really nothing more than Magnetic Tape stored inside of a plastic shell 93 00:05:36,260 --> 00:05:40,740 so it can be handled more easily and so the machine can interact with it automatically. 94 00:05:40,740 --> 00:05:44,630 The audio cassette used a relatively simple system of three access holes, located on the 95 00:05:44,630 --> 00:05:48,630 bottom edge of the cassette, that the erase head, play head and pinch roller could fit 96 00:05:48,630 --> 00:05:49,890 inside of. 97 00:05:49,890 --> 00:05:54,490 This works fine for the relatively uncomplicated process of moving audio tape past two stationary 98 00:05:54,490 --> 00:05:55,530 heads. 99 00:05:55,530 --> 00:05:59,630 But for a video format, the tape has to go in many places and most importantly it has 100 00:05:59,630 --> 00:06:02,350 to wrap around the video Head drum. 101 00:06:02,350 --> 00:06:07,530 Earlier machines had to be threaded manually, but that isn’t exactly consumer-friendly. 102 00:06:07,530 --> 00:06:11,370 To accomplish threading automatically, the machine actually removes some of the tape 103 00:06:11,370 --> 00:06:14,010 from the cassette and pulls it through the path of the heads. 104 00:06:14,010 --> 00:06:18,530 Cout-outs in the bottom of the cassette allow for two spindles to stick up behind the tape. 105 00:06:18,530 --> 00:06:23,030 As the cassette is lowered into machine, the hinged lid which keeps the tape away from 106 00:06:23,030 --> 00:06:27,330 grubby little hands is opened, and once play is selected the spindles move toward the rear 107 00:06:27,330 --> 00:06:30,820 of the machine which pulls the tape past all the necessary components. 108 00:06:30,820 --> 00:06:34,370 Let’s look at some of the components inside without a cassette in place. 109 00:06:34,370 --> 00:06:39,740 The path the tape makes is in the shape of an M. First it travels past this erase head. 110 00:06:39,740 --> 00:06:43,400 When recording, the erase head is energized which removes any signals currently on the 111 00:06:43,400 --> 00:06:44,710 tape. 112 00:06:44,710 --> 00:06:48,180 It’s next stop is the video head drum. 113 00:06:48,180 --> 00:06:52,580 After being wrapped around, it exits the drum and goes past two more stationary heads. 114 00:06:52,580 --> 00:06:55,620 These heads record the audio and a tracking signal. 115 00:06:55,620 --> 00:06:58,780 These two signals are recorded along the edges of the tape. 116 00:06:58,780 --> 00:07:02,770 Obviously the audio track contains sound, meanwhile the tracking signal contains reference 117 00:07:02,770 --> 00:07:05,100 pulses to match each frame of video. 118 00:07:05,100 --> 00:07:09,030 The recorder uses the pulses to maintain the correct tape speed when playing a tape back. 119 00:07:09,030 --> 00:07:13,170 It also allows for the machine to compensate for slight differences between tapes recorded 120 00:07:13,170 --> 00:07:16,510 on different machines, enabling video tracking. 121 00:07:16,510 --> 00:07:20,510 Later machines used the tracking pulses as a sort of timecode, counting each pulse to 122 00:07:20,510 --> 00:07:22,700 determine how much time had elapsed. 123 00:07:22,700 --> 00:07:25,810 The last main component is the capstan and pinch roller. 124 00:07:25,810 --> 00:07:29,230 These components work together to squeeze the tape between themselves. 125 00:07:29,230 --> 00:07:33,020 The capstan spins at a very precise speed, and that’s how the tape is actually pulled 126 00:07:33,020 --> 00:07:34,380 through the mechanism. 127 00:07:34,380 --> 00:07:38,740 Cogged spindles engage with the spools that hold the tape, but they only actually pull 128 00:07:38,740 --> 00:07:41,740 the tape with force when fast forwarding or rewinding. 129 00:07:41,740 --> 00:07:45,440 Otherwise they simply serve to spool the tape and keep it taut, with the capstan doing the 130 00:07:45,440 --> 00:07:46,440 real work. 131 00:07:46,440 --> 00:07:50,160 So let’s go back to the most exciting part, the video head drum. 132 00:07:50,160 --> 00:07:52,290 Here lies the heart of the machine. 133 00:07:52,290 --> 00:07:55,720 If you remember the days of VCR’s, you probably remember this sound. 134 00:07:55,720 --> 00:07:58,919 That’s the sound of the head drum starting to spin. 135 00:07:58,919 --> 00:08:02,930 For machines in the US, it spins at about 1,800 rpm. 136 00:08:02,930 --> 00:08:07,169 One complete revolution makes one frame of video, and since the framerate of US television 137 00:08:07,169 --> 00:08:13,930 is 29.97 frames per second, it spins nearly 30 times in a second. 138 00:08:13,930 --> 00:08:15,730 But where are the heads themselves? 139 00:08:15,730 --> 00:08:17,900 The heads are really tiny and hard to see. 140 00:08:17,900 --> 00:08:22,020 They are tucked away in the slit that separates the two halves of the drum. 141 00:08:22,020 --> 00:08:24,660 All VHS recorders have at least 2 heads. 142 00:08:24,660 --> 00:08:29,919 Because NTSC video is interlaced, each head records half of the video frame at one time. 143 00:08:29,919 --> 00:08:34,330 Upmarket VCRs would have 4 or even six heads, with the extra heads helping to improve image 144 00:08:34,330 --> 00:08:38,479 quality by recording a more precise signal tailored to the specific tape speed. 145 00:08:38,479 --> 00:08:41,599 You might have noticed that the head drum doesn’t sit level with the rest of the machine. 146 00:08:41,599 --> 00:08:45,620 In fact it looks sorta like it was just tossed in there and let to stay where it landed. 147 00:08:45,620 --> 00:08:47,980 But in fact the wonky angle is deliberate. 148 00:08:47,980 --> 00:08:51,680 If you look closely, you’ll see that the head travels diagonally down the surface of 149 00:08:51,680 --> 00:08:52,779 the tape. 150 00:08:52,779 --> 00:08:57,490 One pass of the head, and thus one half frame or field of the video signal, is recorded 151 00:08:57,490 --> 00:08:59,560 on this long distance of tape. 152 00:08:59,560 --> 00:09:01,520 This is called helical scanning. 153 00:09:01,520 --> 00:09:05,090 By running the heads along the tape in this fashion, the tape didn’t have to be nearly 154 00:09:05,090 --> 00:09:09,120 as wide as the 2 inch tape tape found in the quadruplex system, and it also meant that 155 00:09:09,120 --> 00:09:12,279 one pass of the head contained an entire field of video. 156 00:09:12,279 --> 00:09:16,460 See, because the quadruplex system broke up the fields into multiple sweeps, requiring 157 00:09:16,460 --> 00:09:20,860 16 head passes per full frame of video, it wouldn’t produce any sort of intelligible 158 00:09:20,860 --> 00:09:23,470 picture unless playing at the appropriate speed. 159 00:09:23,470 --> 00:09:26,820 This meant fast forwarding or rewinding was done blind, and freeze-framing 160 00:09:26,820 --> 00:09:28,090 wasn’t possible. 161 00:09:28,090 --> 00:09:31,790 Using one sweep for one complete field eliminated those problems. 162 00:09:31,790 --> 00:09:35,330 If you could see the information on the tape, it would look like this. 163 00:09:35,330 --> 00:09:39,890 Two linear tracks are present at the edges, and a bunch of long, diagonal lines fill the 164 00:09:39,890 --> 00:09:40,890 middle. 165 00:09:40,890 --> 00:09:45,020 Each of these lines is one half of one frame of video, called a field. 166 00:09:45,020 --> 00:09:49,310 Each field fills in the whole screen, but only every other line of the image. 167 00:09:49,310 --> 00:09:52,710 Every sweep of the heads along the helical path of the tape made half of the image, with 168 00:09:52,710 --> 00:09:55,290 the other head sweeping by to create the other half. 169 00:09:55,290 --> 00:09:58,950 The VCR would automatically switch what it showed on the television back and forth between 170 00:09:58,950 --> 00:10:02,220 the heads, creating an apparently seamless image. 171 00:10:02,220 --> 00:10:04,790 Now here’s an interesting question. 172 00:10:04,790 --> 00:10:07,450 How is the machine able to actually read the tape? 173 00:10:07,450 --> 00:10:11,580 If the heads are spinning around, they can’t have wires attached to them like these stationary 174 00:10:11,580 --> 00:10:13,770 heads do or they’d tangle. 175 00:10:13,770 --> 00:10:17,920 Early video tape recorders used what’s called a slip ring pickup, essentially a set of thin 176 00:10:17,920 --> 00:10:21,520 wires that brushed against a spinning ring which was electrically connected to the heads 177 00:10:21,520 --> 00:10:22,520 with wires. 178 00:10:22,520 --> 00:10:26,610 These proved problematic, however, as corrosion and wear would introduce noise to the signal. 179 00:10:26,610 --> 00:10:32,350 By the time VHS was invented, rotary transformers were used to provide a wireless coupling between 180 00:10:32,350 --> 00:10:34,470 the top and bottom halves of the head drum. 181 00:10:34,470 --> 00:10:38,150 The actual slices of tape that made up the signal are very thin. 182 00:10:38,150 --> 00:10:43,779 The tape traveled at only 1.313 inches per second, and with 60 slices of video fields 183 00:10:43,779 --> 00:10:48,580 squeezed in the space, you’re looking at a slice width of about .022 inches or just 184 00:10:48,580 --> 00:10:50,910 slightly more than half a millimeter. 185 00:10:50,910 --> 00:10:54,710 To help avoid interference between the tiny tracks on the tape, the heads were assembled 186 00:10:54,710 --> 00:10:59,100 with different azimuths, that is different angles between the tape and the head. 187 00:10:59,100 --> 00:11:02,381 Rather than hitting it straight on, one head would hit the tape at plus seven degrees, 188 00:11:02,381 --> 00:11:04,800 and the other at minus seven. 189 00:11:04,800 --> 00:11:09,000 This created destructive interference between the tracks, thus ensuring each head picked 190 00:11:09,000 --> 00:11:11,029 up only what it was supposed to. 191 00:11:11,029 --> 00:11:16,640 This became even more important as the Long Play, LP, and then Super Long Play, or SLP 192 00:11:16,640 --> 00:11:18,120 recording speeds were introduced. 193 00:11:18,120 --> 00:11:22,840 LP halved the normal tape speed and thus halved with width of the track, with SLP only being 194 00:11:22,840 --> 00:11:24,990 a third the standard speed. 195 00:11:24,990 --> 00:11:28,350 This doubled and tripled the amount of time you could record on the tape, but it reduced 196 00:11:28,350 --> 00:11:33,390 the quality of the image noticeably, particularly when recording at the SLP speed as now the 197 00:11:33,390 --> 00:11:37,500 width of the tracks created by the heads was less than 2 10ths of a millimeter. 198 00:11:37,500 --> 00:11:41,680 The tape-to-head speed of consumer formats wasn’t quite fast enough to reproduce broadcast 199 00:11:41,680 --> 00:11:42,700 quality images. 200 00:11:42,700 --> 00:11:48,470 VHS had a bandwidth of only 3 megahertz, compared to broadcast bandwidth of 5. 201 00:11:48,470 --> 00:11:52,220 This meant that the quality of the signal coming from the tape wasn’t quite as good 202 00:11:52,220 --> 00:11:53,250 as live tv. 203 00:11:53,250 --> 00:11:54,270 Are you ready? 204 00:11:54,270 --> 00:11:57,570 This is VHS quality. 205 00:11:57,570 --> 00:12:01,680 No joke, this has been recorded onto a VHS tape, fed through a capture device, and then 206 00:12:01,680 --> 00:12:03,040 back into this video. 207 00:12:03,040 --> 00:12:05,380 If you’re not watching full-screen, you should be. 208 00:12:05,380 --> 00:12:06,380 It’s awful. 209 00:12:06,380 --> 00:12:11,210 But keep in mind that back in the day we weren’t using massive TVs with 4k displays, let alone 210 00:12:11,210 --> 00:12:12,600 even 720 p. 211 00:12:12,600 --> 00:12:15,680 On an old tube-set, this quality was perfectly adequate. 212 00:12:15,680 --> 00:12:19,120 Let’s talk about those different recording speeds, shall we? 213 00:12:19,120 --> 00:12:22,480 This is what you could expect from a recording made at the standard play speed. 214 00:12:22,480 --> 00:12:26,730 This is the best picture you’re going to get, and it goes downhill from here. 215 00:12:26,730 --> 00:12:31,420 Now I’ll switch to LP. LP’s not terrible, but sound quality 216 00:12:31,420 --> 00:12:32,990 got noticeably worse. 217 00:12:32,990 --> 00:12:35,690 Now here’s SLP. 218 00:13:20,490 --> 00:13:26,220 However, the later development of VHS-HiFi, which stored FM stereo audio within the video 219 00:13:26,220 --> 00:13:30,180 signal of the tape using a second set of heads on the video drum, meant that sound quality 220 00:13:30,180 --> 00:13:33,839 was constant even with an EP tape, and it’s really good, too. 221 00:13:33,839 --> 00:13:39,200 VHS HiFi has a full 20 to 20 kilohertz frequency response, excellent signal-to-noise ratio 222 00:13:39,200 --> 00:13:43,560 in addition to dynamic range, and excellent stereo channel separation as well. 223 00:13:43,560 --> 00:13:47,660 It was very close to CD quality, with many people (myself included) not being able to 224 00:13:47,660 --> 00:13:48,890 tell the difference. 225 00:13:48,890 --> 00:13:53,920 Thus the best way to play 8 hours of music nonstop in 1985 was to record your favorites 226 00:13:53,920 --> 00:13:59,140 on a T-160 tape running at SLP speed on a hi-fi equipped VCR. 227 00:13:59,140 --> 00:14:03,790 The only caveat to VHS-HiFi was that because the audio was recorded along the helical scanned 228 00:14:03,790 --> 00:14:08,670 portions of the tape, the source of the sound had to switch back and forth with the heads. 229 00:14:08,670 --> 00:14:12,790 Our ears are actually far more sensitive to gaps in information than our eyes, so if the 230 00:14:12,790 --> 00:14:16,980 tape was damaged or the heads didn’t line up quite right, you would hear a low 60hz 231 00:14:16,980 --> 00:14:17,980 buzz. 232 00:14:17,980 --> 00:14:21,020 Ordinarily, though, this was a fairly rare occurrence. 233 00:14:21,020 --> 00:14:25,400 As a side note, for reasons I don’t really understand, the LP speed disappeared from 234 00:14:25,400 --> 00:14:26,930 many VCRs. 235 00:14:26,930 --> 00:14:31,790 Though all but the very earliest VHS recorders can play back a tape made at the LP speed, 236 00:14:31,790 --> 00:14:35,339 few made after the 1980’s could record at LP. 237 00:14:35,339 --> 00:14:39,519 I remember as a kid in the nineties being bummed when our new VCR couldn’t record 238 00:14:39,519 --> 00:14:43,410 LP, as I found it a nice compromise between recording time and picture quality. 239 00:14:43,410 --> 00:14:46,730 Oh well, I guess only nineties kids remember... 240 00:14:46,730 --> 00:14:50,840 The longer recording time available on VHS was the main reason that Beta didn’t win 241 00:14:50,840 --> 00:14:51,970 the format war. 242 00:14:51,970 --> 00:14:56,640 Sony’s decision to use a smaller cassette with less actual tape inside meant that the 243 00:14:56,640 --> 00:15:01,520 longest tapes typically held was four and a half hours, compared to the eight + possible 244 00:15:01,520 --> 00:15:02,640 with VHS. 245 00:15:02,640 --> 00:15:07,190 VHS was continually improved during its life, with the most noticeable improvement being 246 00:15:07,190 --> 00:15:09,940 the S-VHS standard released in 1987. 247 00:15:09,940 --> 00:15:16,640 S-VHS, short for super VHS could record a 5.4 megahertz signal with improved tape formulation 248 00:15:16,640 --> 00:15:21,680 and recording techniques, actually providing a better picture than broadcast television. 249 00:15:21,680 --> 00:15:26,380 This was only half-true, though, because while the luminance bandwidth was very good, S-VHS 250 00:15:26,380 --> 00:15:30,090 did not improve the color rendering of standard VHS. 251 00:15:30,090 --> 00:15:34,850 See on VHS and beta as well, the bandwidth required to make the image was dedicated mostly 252 00:15:34,850 --> 00:15:36,930 to luminance, or a black-and-white signal. 253 00:15:36,930 --> 00:15:42,649 VHS used a “color-under” encoding method whereby color data, recorded after the luminance 254 00:15:42,649 --> 00:15:46,460 signal, was essentially drawn on top of a black and white image. 255 00:15:46,460 --> 00:15:50,490 This was done to prioritize image sharpness with the limited bandwidth available. 256 00:15:50,490 --> 00:15:55,100 The resolution of this coloring was by contrast quite poor, on the order of just 12% that 257 00:15:55,100 --> 00:15:56,860 of the black and white detail. 258 00:15:56,860 --> 00:16:01,380 So while the picture of S-VHS was sharper than broadcast tv, the color rendering left 259 00:16:01,380 --> 00:16:02,870 a lot to be desired. 260 00:16:02,870 --> 00:16:06,899 Partly because of this, and along with the significantly higher price tag of S-VHS machines 261 00:16:06,899 --> 00:16:10,330 and media, S-VHS never really went anywhere. 262 00:16:10,330 --> 00:16:12,040 Standard VHS was good enough. 263 00:16:12,040 --> 00:16:17,000 You might be surprised to learn that toward the end of VHS’s life, D-VHS was introduced, 264 00:16:17,000 --> 00:16:18,610 with the D standing for Digital. 265 00:16:18,610 --> 00:16:24,130 It is certainly possible to record digital data onto magnetic tape, and the D-VHS equivalent 266 00:16:24,130 --> 00:16:29,550 of a standard T-120 tape could hold 25 gigabytes, the same as a single layer bluray disc. 267 00:16:29,550 --> 00:16:33,930 In fact, the D-VHS standard included support for 1080i video. 268 00:16:33,930 --> 00:16:37,920 You should definitely check out these video clips from one of my favorite YouTubers Techmoan, 269 00:16:37,920 --> 00:16:41,670 where he shows a demo tape with HD scenes of New York from 1994. 270 00:16:41,670 --> 00:16:46,570 It actually kind of jarring to see street footage of that age in that clarity. 271 00:16:46,570 --> 00:16:51,390 As I close this video out, I hope that you can admire the ingenuity in these old machines. 272 00:16:51,390 --> 00:16:56,030 These intricate mechanisms and the out-of-the-box thinking that led to their creation are just 273 00:16:56,030 --> 00:16:57,030 more fun. 274 00:16:57,030 --> 00:17:02,029 The video head drum solved an unsolvable problem in an ingenious fashion, and the intricacies 275 00:17:02,029 --> 00:17:06,179 involved in the machine just to get the tape to wrap around it are far more interesting 276 00:17:06,179 --> 00:17:09,809 to me than a laser diode and optical pickup reading data off a spinning disc. 277 00:17:09,809 --> 00:17:14,639 We’ll be exploring VHS and Beta as well in more detail, and I’ll also be discussing 278 00:17:14,639 --> 00:17:17,339 the format war between them in later episodes. 279 00:17:17,339 --> 00:17:20,679 Thanks so much for watching, I hope you enjoyed the video! 280 00:17:20,679 --> 00:17:25,329 If you did, be sure to give it a thumbs-up and subscribe to technology connections! 281 00:17:25,329 --> 00:17:32,200 I’m doing my best to keep video like this coming your way. 282 00:17:32,200 --> 00:17:51,509 I’ll see you next time!