Television Broadcast Standards

Never Twice the Same Color was an abysmal system, inferior to PAL or SECAM that Americans were stuck with for fifty years. Having said that, many Americans in rural or exurban areas or in small towns were better off with NTSC than with off the air digital, since off the air digital without a very good RF level is crummy in ways that bother viewers more than the ways in which marginal signal bothered with analog.

The Brits did it right in going from 405 line to a whole new system.

 

Not just rural areas. I live in Arlington, VA which is about as urban as you can get with single family homes. We lived with broadcast digital for about 6 months before we broke down and got FIOS. We picked up over a dozen analog broadcast stations with watchable reception, and a few more that weren't really watchable. We lost a third of them with digital. We picked up a bunch of worthless channels.

 

What do you mean by "We picked up a bunch of worthless channels."? You mean what you got with FIOS was worthless? I swear, I hardly care about anything on U-Verse. I just stick with it because my wife wants to watch the cooking channel, and that TV doesn't have an antenna. When I get around to changing the TV, we'll see what happens…heck, I could buy and rip her cooking shows…except basically she is perhaps the last person in America who just likes to tune in in real time.

 

No, the second and third channels stations broadcast in digital. Most were worthless. Four or five where weather radar, each showing the same radar image and playing different music. I guess the felt they needed to use the frequencies they got in the conversion whether or not they had any content to broadcast.

 

Abysmal compared to what ?

Looking at the history of (analog) television, the original B&W specification for NTSC was published in 1941, and the specification was revised to include color in 1953. That specification came after a brief adventure in the early 50s with a color broadcast technology that was incompatible with older televisions.

SECAM and PAL followed, but they weren't complete until 1967 or so...

I don't agree that the US should have dropped the existing standard after approximately fourteen years to chase a new standard - especially if the primary concern was to please people who had yet to invest in the new technology while abandoning those who had.

For what it's worth, there were analog test signals that were used to define acceptable amounts of analog distortion on an analog transmission system. If the signal stayed within these bounds, the technology worked - as intended.

Remember those two knobs you used to get to adjust color ? I can't remember what each was called, but their basic purpose wasn't clear until you looked at "color bar" test signal on a vectorscope. The color bars would show up as dots on the scope - and those dots were supposed to hit a specific target on the vectorscope. If you turned the one knob the "dots" would move to/from the center of the circular scope. If you turned the other knob, the dots would rotate in a circle. By playing with both knobs, you could get them to all sit in the little spots where they were supposed to. If the signal was degraded to the point where this wasn't possible - it said more about the signal path between Transmitter and Receiver, then it did about the worthiness of the technology.

I'm not really sure who coined the phrase "Never the same color" or what exactly it referred to. My thinking was it was more a comment about how there was no easy way to "eyeball" the vectorscope adjustment by hand. There was also a strange phenomena where certain types of patterns (e.g. a plaid suit jacket), could confuse the circuitry. I remember being told that Johnny Carson liked to wear clothes that weren't optimal.

Solid state circuits were eventually developed that eliminated the knobs and created a more uniform viewing experience. They also may have allowed Johnny more freedom in his wardrobe. LOL

Comparing an analog system with a digital system might seem fair at this point in time - but the reality is that digital television did not arrive instantly - and the fact that it was able to fit inside of the same 6 Mhz carrier used by analog television is a marvel in and of itself.

I remember seeing HD television in the late 80s that was an all analog system used in Japan. I believe one reason this system worked is because Japan is roughly the size of California. There were technical hurdles that prevented it from being used on a wider area... I forget the specifics but it had something to do with not enough satellites in the sky.

Saying NTSC sucked because PAL came along and was rolled out in a different territory much later is a "straw man" argument.

It's not really much different than saying PAL sucked because the Japanese did it right when they rolled out the first HD televisions.

Successful change is incremental.

 

This should be a new thread, maybe the gorts can split it....

Anyway, visiting PAL and SECAM markets (Europe) for the first time Americans were astounded by the superior color and detail on Euro standard TV, especially in the 60s and 70s. OTOH the frame rate was slower and sports more flickery.

I still have several color bar generators and a very nice combo oscilloscope/vectorscope taking up attic space.

 

Look at the PC. It's less than optimal because of a line of backward compatibility....that doesn't even work anymore. Entire new architectures like the then far superior Alpha CPU were rejected because "the old software won't run". Well, it won't anyway and we are still stuck with a lot of legacy inefficiencies in PCs, and by extension in the Intel based Macs too, since contrary to Apple fanboi opinion they are really PCs in disguise now.

Our business maintains an XT level PC system for flashing Motorola radios, which is getting to be a nightmare. It's impossible to reliably flash them on anything else. Mother M doesn't care.

The Brits did right to get rid of the 405 line system entirely (well, they ran a limited 405 separate network for awhile) and we would have done better to get rid of NTSC just like we should have ditched the Wintel architecture in computers, the VOR/DME aerial navigation system, and a few other things.

 

Heh, this came up in a conversation I had today. ATX motherboard designs are simply not optimal but all attempts to replace them with better versions (which allow for better heat dissipation, for example) failed because ATX is too entrenched. PCI and PCI-E slots are essentially upside down, for example, with fans underneath instead of on top.

 

The 405 line system was introduced in 1936, when the BBC Television Service started broadcasting on VHF Band I from Alexander Palace in London. It later spread to other BBC transmitter sites also on Band I, and was also used by the ITV network, albeit on Band III, using a different transmitter network.

625 line TV appeared in 1964, with the introduction of BBC2, this time using UHF Bands IV and V, using yet another set of transmitters. Colour came to BBC2 officially in 1967 with the Men's Wimbledon Final, although there were many unofficial test broadcasts before then. The other two channels joined the 625/VHF transmission network in late 1969, simultaneously broadcasting on the old network.

It took some time to roll out UHF TV to the whole country - for example my grandmother's village only received their transmitter in 1974. It wasn't until 1985 that the old 405 line system was eventually turned off.

 

I think Digital Terrestrial Transmission started in 1998 (taken over by a consortium consisting of the BBC, ITV, and Channel 4 in 2002 after ITV utterly failed initially) and analogue TV was turned off in 2012. This means that the 405-line system lasted a few more years than PAL did (49 vs 45 years).

I doubt the present system will last as long. The present plan seems to be to stop using DVB-T and MPEG2 for SDTV, in favour of DVB-T2 and AVC (presently used by HDTV) by 2018. If that does indeed happen, DVB-T will only have lasted 20 years!

 

The BBC performed their first colour tests in late 1954, using NTSC piggybacked onto the existing 405 line VHF system, broadcast when the transmitters were officially 'off-air'. These tests continued in various guises over the next few years, including some broadcast to colour receivers installed in Parliament, as government backing would be needed for such a service.

In 1962 the government's Pilkington Comittee decided that the UK's colour service should be broadcast on UHF using 625 lines, to standardise with the rest of Europe, but the precise system wasn't specified. The BBC soon afterwards carried out tests on UHF, using a variant of NTSC. They also ran some tests with SECAM, before finally deciding on the German developed PAL system.

 

Pal and Secam were/are not perfect, even less when displayed on old CRT sets, too much flicker in my opinion compared to NTSC.

 

The BBC still runs technical tests using unused parts of the spectrum. During the summer, the empty COM 8 multiplex (which is intended to hold 6 HD channels if anyone ever wants the bandwidth) was used to broadcast UHD tests, including from the official UHD World Cup feeds. I think they were HEVC but can't quite remember. Obviously any set top boxes wouldn't have been able to show these test streams but certain software can, so a few people recorded some parts of the stream to their PCs via DVB-T2 tuners.

They even talk about it in their technical blog. It's quite nice they try to keep people abreast of technical tests and the like.

 

The flicker was because they traded off line count for frames per second to keep the bandwidth in line and because most countries kept their frames per second corresponding with their power frequency, i.e. you had 25 rather than 30 frames in 50 as opposed to 60 Hz markets. It should be noted that there were several variants of both NTSC and PAL in different countries so the TV sets in Country A did not work in Country B, at least without modification. As time went on and electronics became more compact multistandard sets came out. SECAM was a French system used only there because they would not have a German or an English one and very certainly not an American one!

 

This is a misconception repeated for many years, especially by people who've never had the chance to really examine PAL closely. I worked on both NTSC and PAL transfers for 30 years, with the ability to see them side by side on $25,000 monitors, and trust me: they looked the same. Transmissions looked different, but closed-circuit connections and home video essentially looked the same.

You can make the argument that PAL (which stood for "Pretty Awful Looking") was 20% sharper, but bear in mind all the film transfers were running 4% fast, going from 24fps to 25fps, ruining the timing and creating pitch issues in the audio. PAL is not the blissfully-perfect system you think it would be.

I think a lot of people want what they don't have and haven't experienced. PAL was never that good to me; the 25fps "PAL flicker" was very annoying.

In truth, all of this stuff is blood over the dam now. HD supersedes everything and made both PAL and NTSC obsolete.

 

I'm not saying the home video playback was better, but the off air TV in Europe definitely looked sharper and more detailed, and in the days before TV sets had microprocessor controlled self adjustments the color seemed better than what you usually saw in the US, going back to what I saw when I was over there first around 1968, then '74 or '75 and later in the late eighties. The frame rate was lower so you saw more flickering, some people's persistence of vision is lower than others and some were annoyed by that. The film chain issue was because of the collision between standard cine rates and standards in video. If they were shooting 16mm for news over there in 50 Hz 25 frame markets did they not use 25 fps on the film cameras? I seem to remember 24 and 25 settings on selsync boxes.

To be precise, PAL vs NTSC as such is a different argument than the one over line counts and frame rates. If you had a certain analog bandwidth, you traded off frame rate for line count. Britain originally had 405 line monochrome, France originally had something ridiculously higher-maybe 800+-and both went to 625 line, 25 fps as I recall. As I was saying you had, as I remember, PAL at 25 and at 30 frames in various markets.

Analog video is otiose in the US, but as I recall, many international TV broadcast markets are still analog.

 

Doing some research on Google, it seems that the only NTSC standards still in use are 525/30 and all the PAL seems to be 625/25. I could have sworn the original standards for PAL included at least two different frame rates and line counts. I haven't paid attention to video in decades, to be honest.

From Wiki:


Evolution
For historical reasons, some countries use a different video system on UHF than they do on the VHF bands. In a few countries, most notably the United Kingdom, television broadcasting on VHF has been entirely shut down. Note that the British 405-line system A, unlike all the other systems, suppressed the upper sideband rather than the lower—befitting its status as the oldest operating television system to survive into the color era (although was never officially broadcast with color encoding). System A was tested with all three color systems, and production equipment was designed and ready to be built; System A might have survived, as NTSC-A, had the British government not decided to harmonize with the rest of Europe on a 625-line video standard, implemented in Britain as PAL-I on UHF only.

The French 819 line system E was a post-war effort to advance France's standing in television technology. Its 819-lines were almost high definition even by today's standards. Like the British system A, it was VHF only and remained black & white until its shutdown in 1984 in France and 1985 in Monaco. It was tested with SECAM in the early stages, but later the decision was made to adopt color in 625-lines. Thus France adopted system L on UHF only and abandoned system E.

In many parts of the world, analog television broadcasting has been shut down completely, or restricted only to low-power relay transmitters; see Digital television transition for a timeline of the analog shutdown.

http://en.wikipedia.org/wiki/Broadcast_television_systems

http://countrycode.org/tv-standards

At the risk of beating a really dead horse, NTSC was not the first color standard actually broadcast in the US. There was a different one that was very controversially suppressed by banning the manufacture of color televisions because supposedly the Korean War material effort might be impeded. Critics stated that David Sarnoff exercised improper influence over lawmakers in an effort to sabotage the system, promoted by rival CBS, in favor of the later one which RCA had key patents on.

 

I believe you're mistaken, and you're going from memory, which is very fickle. I've actually seen PAL and NTSC side-by-side from the same source, and they are not as different as you might believe. And the PAL was very, very affected by flicker and being at the wrong speed.

Yes, this was the famous "CBS color wheel" system, which had a lot of issues -- one being that the cabinet that enclosed the picture tube had to be as big as the wheel, which was bigger than the picture tube. RCA convinced the FCC that they had made the wrong decision because the CBS system wouldn't work with B&W sets, whereas the RCA system was "compatible color."

Here's a video I transfered many years ago showing RCA introducing their very first color TV sets in December of 1953:



I think there were a lot of politics, "good ol' boys club," and bribes involved in a lot of FCC rulings and other kinds of government decisions back in the day. In this case, I think the RCA system really did have a lot of advantages over the CBS system. But Bill Paley and Frank Stanton were really stung by losing the color standard, and were angry enough that CBS broadcast very few color shows over the 10-11 years that followed. Only in 1965 did they slowly start televising major shows in color, and by 1966 all the networks went full color in primetime.

BTW, one big problem with people trying to remember what NTSC and PAL looked like in the 1970s and 1980s is that very few consumers were aware of the need to calibrate the TV sets according to the right standard. If you used the sets right out of the box, they're bound to look horrible -- but that counts for PAL, too. We actually calibrated our 525 monitors more for EBU standards than NTSC standards, because they were more stringent and better thought-out.

One great thing about PAL which nobody has mentioned so far is that American NTSC was saddled with a "setup" black level of about 7.5 ire units, meaning that the maximum dynamic range you could have in the picture was 7.5 to 100; PAL could do 0 units to 100, so they had another 7% of dynamic range. That actually helped a little bit, but that same idea was carried over to HD, so we still have 0 as black level today. I really believe that dynamic range and black level detail are among the hardest things to do in video -- much harder than resolution alone.

 

I thought that even today TV sets (ie, not monitors) used compressed TV levels of 16-235 as opposed to 0-255. Or are you talking about something else?

 

I think the PAL system's color encoding was less sensitive to the phase shift errors in OTA transmissions that gave NTSC a bad rap. So it's likely that you wouldn't see the difference on direct feeds.

 

In 8-bit color, it's 0 to 255; in 10-bit color, it's 0 to 1023, for data only. Once it's crunched into normal Rec709/EBU1886 for broadcast, then that turns into 16-235 and 64 to 940, respectively. Any darker than that on the low end of the scale, the blacks get crushed; any higher than that on the high end of the scale, the whites blow out.

http://blogs.adobe.com/VideoRoad/2010/06/understanding_color_processing.html

That's exactly right. In the 1980s, the linear speed of VHS was actually slower in PAL, so the VHS tapes wound up looking worse than their NTSC counterparts. But the tapes ran longer (50Hz motors vs. 60Hz).

 

Ah, that's where the conversion takes place - thanks.