These days, if you want to install some sort
of security camera system, you can just run to your favorite big box store or wholesale
club, buy a kit with 4 cameras and a DVR, and within hours have a working CCTV system
capable of recording days or weeks or even months worth of HD, or sometimes 4K security
footage. Now we can even access them remotely over
the Internet, or put them in doorbells, or backup the footage to the cloud, or any number
of things which, depending on your point of view, you may find interesting orā¦ concerning. Butā¦ Not that long ago, we only had the world of
analog video. Sure, videocassette recorders were widely
available, but even with the most generous of tape lengths and the slowest of recording
times, youāre not going to be able to get more than 10 hours or so out of a tape. Thatās not great for security cameras, particularly
if you want to be able to record footage over a weekend when no one is at the office. But this video is running at 30 frames per
second and for surveillance footage, thatās probably more than we need. If there were a way that we could reduce the
frame rate, we could get more time out of one tape. If we recorded, maybe, only two frames per
second, weād still have a pretty good record of what happened, and we could get 15 times
as much footage. Well, that idea did come to fruition in the
form of the time-lapse VCR. Iāve known about these things for years,
but there have always been some nagging questions in my mind about how they work. For example, most VCRs just kindaā¦ suck at showing a still image. If you hit pause on this one, youāll inevitably
get some sort of snowy garbage at the top or the bottom. In later years, a digital frame buffer would
grab a snapshot of whatever you were playing so that there could be a nice clean still
frame, but a time lapse VCR thatās RECORDING footage, how does that work? Now I could do some research and try to find
out exactly how a time lapse VCR is doing all the magic stuff it does, but it sure would
be great to just have one that I could poke around with. Oh right! This is a Sony SVT-3050. You can tell that this is a legitimate piece
of A/V equipment because of its two-tone beige and brightly colored transport buttons. Oh yeah. Matte black? Heh, this is where itās at. Seriously, why was so much professional A/V
equipment from the this time period made in this particular color scheme? Itās like itās trying its best to be plain. From the front, this looks like any normal
VCR save for its relatively few buttons (most are hidden behind the door) and surprising
omission of the VHS logo even though this uses VHS cassettes. Are we bitter about something, Sony? Weāll get to that in a minute because there
is some mystery as to why the labelās missing, but what gets weirder is when you come āround
to the back. For starters, you wonāt find standard coaxial
jacks for a television tuner. Nor will you find standard RCA jacks for composite
video. Instead, youāll find BNC connections, which
were and are to this day very common in security camera applications. Youāll also find a bunch of screw terminals
for various things like timers and alarms. For example, the unit can send out an alarm
signal if the tape becomes jammed or it runs out of tape. And it can also accept an alarm input to start
recording. When I got my hands on this, the first thing
I did (as would anyone, I presume) was to open the case. I wanted to see just whatās inside this
thing! Oh. Thereās a circuit board in the way. No matter, weāll just pop that up, and look
at that! There are little pegs made specifically for
holding the board up and out of the way for servicing. Thatās neat. Under the board was a completely normal looking
VHS transport. Real talk, if you are into old VCRs like I
am, you actually should open them up before you test them to make sure nothing is stuck
which might cause it to eat a tape. This one indeed had something preventing the
take-up spool from turning, and after exercising it a bit the problem went away. But, had I not checked, it may have ruined
a tape. These are the sorts of life changing tips
you can find only here on Technology Connections! One of the more curious things in here is
the use of a modular power supply. You probably noticed the standard IEC C13/14
connector on the back, and itās clear that it wouldnāt be very difficult to swap out
this power supply for another. This not only makes repair easier, but it
also means that the same chassis could be used in many markets. OK, so with it operational, I popped a tape
in and starting messing with the playback. On any speed but the normal 2 hours, the tape
simply juddered forward one step at a time. Is that really it? I had imagined that maybe the head drum would
spin at a slower speed, or that the machine would behave in some other strange way, but
it appeared that this was simply stepping forward one frame at a time. Lots of VCRs can do thatā¦ so what makes
this special? Well, keen eyes may notice that the quality
of that still frame is perfect. Thereās no snow, thereās no jitter, and
there isnāt even any sign that thatās a digital frame buffer. To be sure that this wasnāt playing tricks on
me, I touched the spinning head drum while watching the screen of the TV, and sure enough
the picture was distorted along with my touch. So, this picture is coming live from that
tape. That alone isnāt so surprising, as many
high-end VCRs with four heads can do that. But what is a little more interesting is that
it not only has to do that when playing a tape, but it also has to do it when recording. After much searching, I found a great source
describing how time-lapse VCRs work, and one of the more remarkable things about them is
how precisely they can move the tape itself. See, in normal recording and playback, the
tape is continuously moving at a rate of about 1.3 inches per second, or 3.3 centimeters
per second. This means that with each sweep of the recording
or playback heads, which happens 60 times a second on an NTSC machine, the tape has
actually moved roughly half a millimeter. That means that the end point of the sweep
is about half a millimeter to the right of the beginning, imparting a slight angle to
the track. Thatās why a two-head VCR canāt display
a nice still frame. Without getting too deep into explaining analog
video, each head is responsible for one half of the frame, or one field. With a two head VCR, if the tape stops, then
the heads are suddenly misaligned a little bit. One head will start showing the correct thing,
but it will drift into the adjacent track. The same thing happens when the next head
sweeps. In essence itās always reading the wrong
thing for at least some part of the frame, and the result is a noisy, incomplete picture But a 4 head VCR actually has two heads passing
by with each sweep. Itās capable of reading either the odd or
even fields at any time, and can switch between them on the fly. This allows it to perfectly display either
the odd or even field without noise bars. Thereās a great link in the description
if youād like to learn a little more about the specifics here. Anyway, thatās all fine and good, but whatās
most interesting here is how the machine records onto the tape. It needs to get that correct angle otherwise
the signals will be completely out of spec from VHS, and it wonāt be able to play them
in fast motion for the purpose of searching for the moment that your restaurant was robbed. Or whatever. And that is what makes this more advanced
than your average 4 head VCR. When recording, the heads are completely inactive
except for when they write that single field onto the tape. Most of the time theyāre simply spinning
for the fun of it. And hereās the kicker. The writing action is perfectly synchronized
so that it happens just as the tape is being advanced to the next position. This means that the machine actually is recording
in a completely normal fashion. But, it is able to start and stop the tape
with such precision that although itās recording up to 86 times slower than normal, the signals
on the tape are unaffected. Take a look at this slow motion footage. Iāve placed a marker on the tape so that
we can see it advance. The tape is completely stationary, but the
moment that head is aligned with it, it moves. And as soon as the next head is in position,
it stops. This extremely precise control of the tapeās
movement, along with the idling of the recording heads until the moment that next frame is
to be recorded, enables the machine to make intermittent, single-field recordings onto
the tape. Pretty neat. Now hereās where things get a little weird. Keen viewers will have noticed that there
is an audio input on here. If youāre familiar with how audio is stored
on a non-HiFi VHS tape, youāll know that itās recorded linearly on the edge of the
tape, just like a normal audio cassette. How would audio work if the tape is moving
in steps? Well, the machine can only record audio in
the normal 2 hour mode, and the 12 and 24 hour time lapse modes. It canāt record audio in the slower speeds. But, this means that when recording in the
12 and 24 hour modes, the tape isnāt advancing in steps. Instead, itās continuously moving very slowly. The images are still stored in a reduced frame
rate, but the continuous motion of the tape enables sound, albeit very very terrible sounding
sound. So, the same thing happens. The heads only write in individual bursts
for each frame, but we get an odd consequence now. See, if I want to play the tape back with
sound, it canāt play the tape back very well. Itās certainly not awful, but there are
noise bars and other anomalies. If we want perfect quality, we need to switch
the sound off, and then it returns to the stepping mode that it was using before. And this may give us a clue as to why the
machine is missing a VHS badge. Technically, the format specifications arenāt
being broken if it is recording in steps like this. It is recording a normal SP signal on the
tape, itās just doing it intermittently, one field at a time. But this weird extra super duper slow speed
doesnāt conform to that standard. Is this THE reason? I canāt say for certain. The S-VHS variant of this machine, the Sony
SVT-3050P, does have an S-VHS badge on the front, and it, too can record audio in 12
and 24 hour modes. Soā¦ the missing logo may remain a mystery. But weāre not done yet. Did you notice that āFaroudja laboratoriesā
mark on the back? Yeah, that got me curious. Who are they and what do they want with my
VCR? Well, Faroudja Labs was quite famous for analog
video processing technologies, in particular devices called line doublers. These could take a low resolution image, and
double the number of horizontal lines of resolution, to give it an apparent resolution bump. This device would really benefit from a line
doubler, because it records just one field at a time. Each still frame is only half the resolution
of a normal television signal, and for something like security cameras where you might want
to be able to identify who is stealing your stuff, thatās not good. Now Iāll admit, you canāt get more detail
out of an image than was already there, so the extent to which a line doubler may help
with tasks like identifiability is up for debate, but itās clear that this technology
is helping. Part of why these still frames seem remarkably
clear may simply be due to Faroudjaās video processing prowess. Now I canāt say for certain that there is
a line doubler in here, but knowing what Faroudja had done in the past, it seems very likely. At the very least, something of theirs is
making this a very sharp picture for what the raw signal is. So, that pretty much wraps up how a time-lapse
VCR works. Itās a lot less magical than I thought it
might be. More or less itās just a standard VCR. There were some special considerations to
using it, however. With a normal video tape, the tape is only
touching the spinning head drum for a few seconds at a time. But with this machine, on the slower recording
speeds, it might be touching that drum for a few minutes at a time, and this could quickly
wear out the tape. For this reason, manufacturers would recommend
that you discard your tapes after a certain number of uses. Some would say to only use a tape twice if
it was recorded with the slowest speed. When these were in common use, youād need
to balance the desired detail of the recording with your business hours and when the tapes
could be changed, and how long of an archive you need to keep (for legal purposes, usually
at least a month of recordings). So, youād need to have something like 10
tapes on hand, use them in a rotation, and discard them after theyād been used perhaps
a dozen times. For a 72 hour recording, this would let you
use 10 tapes for perhaps a year before needing to replace them. And of course, a 24/7 duty cycle for a VCR
isnāt the kindest thing. It was recommended that you replace the video
heads on this at least every 10,000 hours (which works out to pretty much every year). You can still find the drum, the 2N4N-Q, for
sale from people who specialize in security equipment. And it looks like this machine has had its
heads changed at least once. Poking through the menu shows that itās
been powered on for 25,716 hours, but the video heads only have 314 hours on them. Now, it could be that this machine was set
up to only record in an alarm condition. This may be the original head, and it was
simply idle the vast majority of the time. There doesnāt seem to be a way to determine
if that counter has been reset, so I suppose Iāll never know for sure. But before I go, I havenāt answered one
particular question about these things. What happens when you have multiple cameras? Well, thatās a fairly deep rabbit hole so
Iāll be brief. One option was to use whatās called a quad. This splits the incoming signal of four cameras
into a single display showing all four at one time. The major disadvantage here was the very poor
resolution of the recorded video, as each camera only got one quarter of the screen. Another option was a switcher. This would simply cycle through each of your
cameras one at a time, showing Cam 1, then Cam 2, then Cam 3 and so on. Youād get a full resolution image, but you
couldnāt see what was happening on any of the other cameras when one was being shown. It also makes reviewing recorded footage a
littleā¦ nauseating. The coolest solution, albeit the most expensive
one, was a multiplexer. These would combine the signals from all of
the cameras, and send them over a single wire by rapidly switching between them, and using
the vertical blanking interval to signal which camera is which. When you want to see just one, the multiplexer
would use a frame buffer to show only that one camera at a reduced frame rate. The beautiful thing was that this also worked
with a time-lapse VCR like this one. But, youād have to synchronize the multiplexer
with the VCR (using the switch out terminal), and youād also have to deal with an effective
frame rate thatās even worse than what the VCR is natively recording. See, if the VCR is recording 4 cameras, and
itās recording at a rate of 4 frames per second, those four frames are split between
the four cameras, meaning that each camera only gets a recording once per second. So, while you did get to record four cameras
on one tape with the full resolution, you would get a seriously reduced update frequency. That was a significant trade-off, but it was
cheaper than having a dedicated VCR for each camera. If I ever get my hands on a multiplexer, Iāll
revisit this video because Iād love to see how it all works. Iād be curious to know what exactly it stores
in the blanking interval, and it may be fun to set up a CCTV system using vintage equipment
like this. But for now, I hope you enjoyed this video
on the time-lapse VCR. Itās a lot simpler than I thought it might
be, although it ended up being far more mysterious than at first it seemed. As Iām sure you know by now, I end my videos
with a thank you to my amazing patrons, but this time I have more than one reason to thank
them, and someone else to thank, too. This video topic was a viewer suggestion! A friendly gecko named Torrance reached out
to me and wanted to know a little bit about these time-lapse VCRs. Iāve always been curious myself, and thanks
to the people who support the channel on Patreon, I was able to go and buy one and poke around
with it. And in addition to their generous financial
support, this time around the Patreon crew came to my rescue by helping me figure something
out about this machine. I was under a very mistaken assumption about
how this thing was making such a great still-frame, and thankfully you sent me some great resources
(including one linked below) that made me realize I was really overthinking this! So, if youād like to send in a video topic
suggestion, please do! You can leave them here in the comments, you
can reach me on Twitter @TechConnectify, or you can check out the Technology Connections
subreddit linked below. Down there youāll also find a link to my
Patreon page. With direct viewer support, this channel has
really taken off and there are very exciting changes coming pretty soon. If youād like to make a pledge of your own
and get perks like early video access, occasional behind the scenes footage, and general updates
before anyone else, please check out my Patreon page. Thanks for your consideration, and Iāll
see you next time! ā« violently smooth jazz ā« ...because of its two-tone beige and brightly
colored transport (unintelligible babbling) Hu huh! Huh huh! [And other weird noises] ...to make sure nothing is stuck and might
cause it to eat a paā¦ (laughs) Eat a pastry! Did you notice that Faroudja Laboratories
mark on that back? Well that got meā¦ Is it laboratories or technologies? Itās both! OKā¦ With a normal videotape, the tape (pauses) Yeah, dang it that was right. Mmhmm! Say the lines as written, please. Itās a lot simpler than I thought it might
be, although it ended upā¦. (sigh) [very high pitched squeaky sounds]
I think there are some cool topics you might be interested in covering in film photography, or at least mention as interesting technological tidbits.
APS (Advanced Photo System) film, in particular, is a rather advanced film format. One of the oddest features of the format is that you never see the film itself, even after it is developed. It comes in a cartridge, like in 35mm film, but the film is always stored in that cartridge. The camera automatically extracts the new film from the cartridge when you insert it and puts it back inside after you expose it. However, when you develop the film, the developed film is returned to you still in the cartridge instead of being cut up in to strips like normal 35mm film.
You might have seen a video by Techmoan where he looked at a device that even took advantage of the developed film being stored in the cartridges.
The most interesting thing about APS film is that it stores image metadata about the images you take on the film itself. It could record information such as aspect ratio, date, time, exposure data (shutter speed/aperture), and even a caption! The metadata was later read by the developing/printing equipment to automatically determine print size, improve photo quality, and print text on the front and back of the photo print.
APS cameras could store metadata on the film in two entirely separate ways; either magnetically on a ferro strip that was on the film, or optically using a light source around the edges of the film.
Because film was stored in the original cartridges, it also necessitated that a unique serial number was assigned to every cartridge of film produced, which was also printed on the back of any given print from that roll. The serial number allowed you to figure out what roll of film contained what pictures and order reprints.
One other weird quirk of the format was that the same film could store 3 different aspect ratios of photo. High Definition (16:9), classic (3:2), and Panoramic (3:1).
Lastly, one other tidbit you might find interesting is the DX numbering system used for both APS and regular 35mm camera film.
You may have noticed a silver and black checkerboard pattern on the film canister of 35mm film. This is the DX system, a standardized identification system for automatically telling your camera about the film you just put in, either optically or electrically by physical contact, as silver squares conduct while black squares insulate.
The checkerboard contains two rows of six pixels and uses standard DX encoding. The left-most pixels on both rows will always be silver, as they serve as the common ground connections. The first row of pixels indicated the ISO speed of the film, which allowed for indication of ISO speeds from 25 to 5000. The second row of pixels indicated two different things. The first three pixels indicated the length of the film, from 12 exposures to 72 exposures, and the last two pixels indicated the exposure tolerance of the film, such as +/- 1/2 stop, +/- 1 stop, etc.
Not every camera took advantage of the checkerboard pattern and some that did only looked at the 1st row of pixels, to determine the film ISO.
Right above the checkerboard pattern was a regular barcode, also a part of the DX system. This regular looking barcode contains 6 digits. The first digit was a unique manufacturers code, the last digit indicated the film length, and the middle 4 digits is a hash number that identifies the specific film emulsion. This barcode was scanned by many film-processing machines to learn about the cartridge being inserted for developing. It would inform the machine about the length of the film and I am told that it could also inform the operator if they had inserted an incompatible emulsion type for that machine (such as if they were attempting to develop traditional B/W film in a machine containing C41 chemistry).
The last part of the DX system is the film edge barcode, which is a barcode optically printed on to the edge of the film during manufacturing. These barcodes provided a synchronizing clock signal as well as information on film type, manufacturer, and particular frame number.
There's been a lot of interesting thought and technology put in to simple camera film, so I thought you might find those interesting!
I installed and maintained the old school CCTV VCR systems with multiplexors for well over 10 years. That same model VCR too, but I like the LC300 more due to the smaller size. That VCR brings back a lot of memories. You got all the details right, but let me add a few more.
With 24/7 operation, I found the VCR heads to last about 2 years. The VCR has a beeper that would let you know when the head quality got too low. It cost about $400 to replace the head. They are not cheap. About half the cost of the VCR. I can't recall any other issues with the Sony even under 24/7 operation in horrible environments.
Most of the time I put all the CCTV equipment in the attic or some other place hidden in the restaurant. Then when someone broke into the store in the middle of the night, they would not take the tape.
I replaced tapes every 60 days. No rotation. Most of the time I would set them to 48 hour loops as that gave it enough time for me to get on site and pull the tape if something happened.
This gave about 8 fps recording if I recall right. The VCRs have an alarm input that can be wired into the building alarm system. Alarm goes off and the VCR switches to 8 hour mode.
If longer recording time is needed, two or more VCRs could be synced by the rear "series" connections. A few seconds before the tape ended on one VCR, a second would start recording. The first one would hit end of tape, rewind and be ready. When the second one was near done, it would signal the first one to start recording. In affect, it would flip flop recoding between two VCRs. I believe you could have more, but I never used more then two.
The flip cover on the front of the VCR is not to hide the buttons for a clean appearance. But to keep the store manager from messing with the settings, but still let them use the transport buttons.
You are correct on how it "syncs" to the multiplexer. That syncing really worked quite well and made the system useful for many years. Far better the using a quad and affectedly reducing the video quality to 25%.
One other trick of the multiplexer is motion detection. At 8fps with a 16 camera multiplexer, a single camera would only get an image recorded every other second. However with motion detection, if a camera sees motion, it would switch to it, every other frame. In affect, the cameras at the front counter showing lots of movement would have a high fps, and the camera facing the back door that see little motion, would have a very low fps.
The multiplexors stored the frame information in a proprietary way. One model would not read the frame information from a different models tapes in general. So to review the tapes back at the office, you would have to have the same model multiplexor at the office.
Why not just watch it at location? Because depending on the "incident" if you where looking for something that could have happened over a 10 hour period, you had to watch the tape for 10 hours. An example of that is if a black handbag walked out the door and you need to know who took it. So you have to watch the door video and look at everyone who leaves to see if they have a black handbag. Doing that in a hot office on a 10" CRT is not fun.
Once I found the video evidence, I duplicated it on to a normal VCR from the video out on the multiplexor. But there has been times I had to take the VCR, TV and multiplexor down to the police station for them to review too.
Oh, and the multiplexor would "encode" a time and date stamp in the video. So the time and date would not be burned into the video blocking useful screen area.
And one more thing, in most US states, you could not record and keep audio for more then 24 hours (I think, not sure if that still applies). And I think you needed a sticker on the door saying you where recoding audio. I tried to record audio a few times, but in a busy restaurant, a hidden smoke alarm looking mic, is near pointless in anything but a quiet office. It just picks up way too much background noise.
I love how far this channel has come. It was always good, but your charm just keeps on... charmening!
Can I make a viewer request to talk about early high resolution video production?
My interest in this started with reading about how the 1964 TAMI show, a video to movie release, was produced with RCA TK-60 cameras modified to record the French 819 line format at 25fps and use a telecine method that reduced the visibility of lines on the film.
Watching a recording, the resolution is extremely impressive with the visible artifacts of the Image Orthicon tube.
This got me reading that latter productions (I believe including Richard Pryor's 1979 live performance) where produced with higher than NTSC cameras and taping equipment before being converted to film for public performance.
This seems to be the extent of what I can find on the subject but would love to learn more.
It also looks like there were some CCIR standards for CCTV that were higher than ntsc line counts.
Will you do a video about Video8/Hi8? It's a really interesting format. I have this really cool portable Hi8 VCR from 1998 (Sony EVO-250). I also have 3 Hi8 camcorders. A Hitachi from 1992, and 2 Sony's from 1999 and 2001. They wanted to make Video8 a home format instead of just a camcorder format, and they made Video8 VCRs the size of VHS VCRs. Sadly I can't seem to get a good image from the heads of the portable VCR, they are possibly dirty. But I can send it to you for a small fee if you return it to me, if you ever decide to to a video on Video8 in the future. I know you mentioned Video8 at the end of your Betamovie video, but you should do a better look at the format.
Here's the output from the Hitachi camcorder: https://i.imgur.com/En3NKlZ.png
Here's the output from the Sony CCD-TR818 (2001): https://i.imgur.com/1oKQv1k.png
Here's a picture of the VCR: https://i.imgur.com/5ORHfAw.jpg
And hooked up to my TV (however, it's not really working): https://i.imgur.com/lV6y3Lz.jpg
I have a topic suggestion for a future video:
Keeping with the theme of VHS, Alesis made a range of 8 track digital audio recorders that recorded on SVHS. There were several revisions with different resolutions and such. Iāve generally heard them referred to as āAlesis ADATsā, however each series had a specific model number and Alesis kept using the ADAT name in future hard-drive based recorders.
Itād be interesting to see exactly how the heads record the data onto the tape (are the heads special in some way, does the tape run at a faster speed, etc.). Many of these recorders had loop functions, pitch control, and a lot of audio editing features built in.
One model I have was actually made by Fostex weirdly enough. (Fostex CX-8)
Iād be willing to lend you one or, if that wonāt work, you can usually find them on your favorite auction website for fairly cheap ($50 - $100).
Below are some resources that were on the first page of google:
Wikipedia https://en.m.wikipedia.org/wiki/ADAT
Manual for one of the later models http://pdf.textfiles.com/manuals/STARINMANUALS/Alesis/Manuals/ADAT%20LX20.pdf
I can answer any basic questions you might have (different models, setting one up, the different inputs/outputs), but Iām not proficient in the technology/engineering side of it (yet).
Thanks for reading! Keep up the great videos!
I know I'm late but what would happen if you play the time lapse tape in a regular VCR?