In the 1970s, GE devised a method to automatically correct luminance and chroma imbalances occurring in the broadcast chain between studio, transmitter, and consumer receiver:
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For whatever reason, by the mid-1990s, the system fell out of favor, and consumers were once again left to their own resources as to where their TV picture adjustments should be set.
Considering how modern digital TVs appear as shipped from manufacturers, and considering just how high a level of inaccuracy the viewing public are presently unwittingly willing to endure, could such an "automatic calibration" system, similar to VIR above, be implemented today?
What chance have they got for sorting that out when they can't even get lip sync right in the UK. Surely the digital set-top pictures should hold the picture back until audio and video are in sync?
A few years ago, a relative of mine bought a Samsung LCD TV along with a DTH satellite system. The TV's picture controls don't work when used with the DTH set. The default settings of the set-top box had contrast and colour waaaay too high and did not remember user settings. I couldn't find any provision for manually saving the settings either. Whenever power is turned off and on and even when changing a channel, one had to adjust the picture settings all over again. I remember thinking "How can such clever people (the manufacturers) be so stupid in other things?"
That VIR system was more of a gimmick to me, basically added an indicator lamp that gave false-security to the owner that "something" was working. My point is, it only made sure the transmission from studio to the home was in order, but it didn't know anything about the condition of the set.
If the picture tube was aging and had like a blue tint to it, the VIR did nothing to help that. If the set wasn't calibrated well, needed convergence, gray scale tracking, same thing, VIR did nothing.
Remember when that was developed, everything was analog, from the camera recording in the studio to tape, copying the tape, pumping the signal up and down from satellite, the franchise tv stations who may of received tape copies in the mail, to their own equipment, studio and transmitter. Anything in that chain could alter chroma, phase problems with that, black levels which changed the brightness to contrast ratios. The VIR was there (not being altered with all that) to act as a reference.
The problem was, most people never noticed a difference with VIR stations and non-VIR and like I said, it didn't compensate for out of spec tv's. Things were not that bad really with most stations having engineers that mostly did quality control, monitoring the "AIR" signal, live.
With the way things are now, everything is digital, bits-is-bits and except for dropouts when the error rate is exceeded, I don't think a digital signal from the studio can be altered all that much, no matter how it's transported from A to B.
I think what you need to do is explain why you think it's needed? I mean there are crappy lcd/led tv's and good to excellent ones but like they say, you can't make a silk purse out of a sows ear.
Bruce Esquibel wrote: "I think what you need to do is explain why you think it's needed? I mean there are crappy lcd/led tv's and good to excellent ones but like they say,..."
I believe it's needed(but like VIR can be disabled) because the vast majority of set owners, since
2000 anyway, don't even know their flat panels
*have* menus, let alone know how to set picture adjustments or anything else in them for that matter.
I'm a huge advocate *for* accuracy in picture & sound, but also an opponent of "personal preference". Personal preference to me is like visiting the Great Pyramid or EIffel Tower and wishing they could be colored green, or pink. They are the colors they are, and those colors/surface textures should be rendered accordingly on a well set-up display.
I first calibrated an old CRT with Avia 10 years ago, and after seeing the results, I never looked at TV the same way. Now when I see display in default mode(usually Vivid or Dynamic), or user preference(Sports mode), i just can't look at it for more than a few minutes before realizing something needs to be done! The guy reading the network news does not wear eye shadow! (sharpness cranked too high). LOL
How would this work? Unless the tv have a camera to see the lighting condition, the only thing it can do is to adjust the contrast, hue, etc to a preset level, which could just as be done at the factory.
But then again, many sets are probably adjusted to look good in the shop, not in the living room.
That's true, but the VIR TVs were all solid state, and were amazingly consi stent from sample to sample as opposed to 60s TVs which took at least a hal f hour of dealer prep to get right. Back then, they came out of the box fa irly well calibrated and even so, a good portion of them were sold by servi cing dealers who would tweak them.
As far as the VIR circuitry, it was gimmicky in nature but was not a gimmic k from a technical standpoint. They did indeed work and considering the IC technology of time, were actually amazing. I can't recall though if the cu stomer could add or subtract some chroma to get the VIR adjusted levels mor e to their liking, but I do recall some customers back then had bizarre ide as of what good color looked like.
I do recall them not being trouble free though, and GE provided a simple wa y to bypass the VIR module if it crapped.
Not really a gimmick. It did work but only adjusted the chroma level and ph ase. (color and tint) It could have done more, like keep the gain and pedes tal (contrast and brightness) right, now that sets had DC restoration. They decided not to do that and I think I understand why. Nowhere in the world did people adjust their TVs like here. Some had the color too high. Alot of them, and I mean quite alot of them had the faces too red with the tint (o r hue) control. Those people would say I set the faces too green.
Over in Europe, with a slightly more modern system there was no hue or tint control. The phase errors in NTSC were caused by vulnerability to frequenc y response errors and a few other things to which PAL for example was immun e.
The VIR or VITS (slightly different but very similar) was not intended to s et the color on people's TV sets. It was intended for the stations to use. In NYC there was a control room for the major network, let's say NBC. They originated the shows on the network, like the national news and other natio nwide programming. The loop went all the way around the country and it was of course degraded by the time it got back. And delayed of course.
But the VITS or VIR was hat told them alot more about the signal quality. I t had one line of NTSC color bars, one line of staristep and one line of mu ltiburst. (later, closed captioing was right under it) They could have used the stairstep for ghost cancellation I think but never did. The technology was not cheap enough for consumers. Phillips DID develop a ghost cancellin g system and I think the stations did start =sending its specified signal during vertical retrace, but I never saw it in operation and have doubts a s to whether even one single unit was sold. But Phillips built TVs had a vi deo in/out loop for it just like a tape monitor on an audio amp. (for a few years only)
On a scope with dual time base you could separate those lines out from the vertical retrace interval and see the actual waveforms. When TVs had a vert ical hold control you could roll it down and have a look. Another cool thin g that was in there was a signal for the commercials to start.
That was a white rectangle at the upper left of the frame, so far up in the corner that no TV of the time would show it due to overscan and/or not a q uite rectangular screen. It was only on network programming, obviously that tells the local stations to cue their local commercials which would be int erspersed with the national commercials. I am pretty sure those (imperfect) commercial "zappers" used that signal.
Damn do I have alot of useless information ! All of this is completely obso lete.
A bunch of them actually had light sensors and would adjust to lighting con ditions.
Hmm, not sure if I ever saw onee with that AND the VIR system. the only two brands I can think of ith VIR were GE before they got bought by Thompson a nd Sylvainia, GTE Sylvania, not Phillips. Both of them did have the light s ensor in some models but stillnot WITH VIR as far as I can remember.
Yeah but you are talking about two different things.
What you want (or is more along the lines) is something like the modern day surround sound receivers where they come with a microphone and some kind of software in the receiver.
After you install the receiver and hook the speakers up, you plug the mic in and place it where you usually will be sitting. Then when the receiver is in the setup mode, it plays different white noise, sweep tones, shifting around speaker to speaker. Then when it has all the info from the mic, it can set the EQ and volume levels per channel by itself.
Probably not all that accurate (although the one in my Yamaha did say one speaker was out-of-phase, and it was internally) but better than having nothing.
To make the tv generate patterns or color sweeps is probably trivial and cheap, but what would you use for a camera to feed back to itself? You can't exactly include a $1000 hd camera with a $400 tv but the idea would be the same, point the camera at the screen from where you normally sit, let the tv run the tests, the camera feeds back to the tv and let it adjust itself to room settings.
It may not even has to be a camera in the conventional sense, just some kind of optical sensor that can detect white/black and color intensity or something. As long it know what to expect from the tv (and when), it probably would come closer than playing around with the menus manually.
Just saying it would have to be more along this line than anything like VIR being added in.
The original premise of VIR is that the TV would be aligned with a luma/chroma/phase/peak signal sent 60x sec from the station on a specific scan line.
VIR was not something done in the home, with test patterns and a camera or sensor mounted to the screen. That is called calibration.
The key phrase here is: "aligned with the station". Of course, there could be the option, in this glorious digital age, of user override of certain adjustments, such as the Backlight on LCD/OLED TVs, to compensate for specific in-room viewing conditions, day vs night, etc.
But at the very least, the color, hue, and sharpness would be locked in automatically.
And it would still be up to the user to locate and disable non- standard eye-candy such as "auto skin tone". "noise reduction", or "motion sensitive lighting". Basically, all just effects that add nothing(useful anyway!) to the image.
Efter mange tanker skrev snipped-for-privacy@gmail.com:
This would not be neccessary on european PAL (Phase Alternate Line),where alternate lines are in opposite phase, cancelling any phase shift in the chroma signal, only in the US NTSC (Never Twice Same Colour) system.
This is digital, it is unchanged from mixing console to tv, the only variable is how the pixels on the screen responds to the signal, so VIR would not help here. The only thing which needs adjusting is this response and allowance for lighting conditions in the wieving room.
Sorry if the premise of this thread was not clear. The primary target of a digital version of VIR is the consumer end. My whole focus is exposing as many home viewers as possible to an accurate picture.
The "factory default" settings, such as they are, do absolutely nothing for home/office lobby/hotel foyer TV viewing. Digitally transmitted VIR would "reach inside the consumer set, and automatically adjust the contrast, brightness, color, hue etc, regardless of where the consumer or factory adjusted them to, to match and pass through the station's output directly to the screen.
Local override of backlight and black level could still be allowed to compensate for any viewing conditions from pitch dark to high noon.
VIR would still not apply to auxiliary inputs(VHS, DVD, Blu Ray, HDMI, etc.).
Den 28-04-2015, skrev snipped-for-privacy@gmail.com:
The analog VIR was to override transmission errors and ensure that the hue the station sent was the same as what the receiver got, regardless of distance, atmospheric conditions etc.
You still had to calibrate your tv-set, but theoretically just once, not every time the disturbances changed.
In the digital age, when the mixer sends 75% green, 20% red, 15% blue, the tv gets the same.
Even if your "Digital VIR" tries to set every receiver to 65% brightness, 50% contrast, 68% colour saturation, you have no way of being sure the pictures are looking the same on Sony, Samsung or Chevrolet TV-sets, new or old, plasma, LCD, LED etc.
Unless you have an equally calibrated sensor/camera at the VIR's disposal.
When the GE VIR equipped TV picked up the VIR signal, it would set it's chr oma level and phase to what the broadcaster set it for, not any preset valu e. The theory is that it didn't matter what happened to level and phase du ring transmission, retransmission and final reception at the TV. The VIR s ignal told the TV what level and phase to set the chroma to.
It was defeatable with a switch. I remember one station where the color we nt all green on every VIR TV I saw for a whole summer.
Again, when digital, the level and the phase of the chroma at the TV (if that even makes sense in the digtal world) is always the same as the broadcaster sends.
You can't set all receivers to the same colour, saturation and hue values, because TV's varies, both between models and manufactures, but also ageing.
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