The HackTV project has recently added experimental functionality to generate the test cards of the PM5644/85, so now you can try out PALplus yourself without having the generator I've used in this video. Check its github page for updates on this.

Here in the Netherlands PALplus was almost exclusively used for testcards. When i did see a transmission in PALplus (mostly films) i found the the moving blue objects in the black bars highly distracting on a regular PAL TV. Lowering the brightness to try to mitigate the problem was not an option as this would lead to black crush. I think this was the major factor in the poor adoption of PAL plus. All the people who invested in PAL plus tv's must have been very disappointed with their purchase! Anyway thanks for the great video on this very interesting part of tv history Matt!

It's interesting to note that the case of the PALplus decoder is identical to that of a satellite receiver (Luxor MAC IV) manufactured by Nokia in Sweden in the mid 90's. There are two unused card slots in the front that were to be used for Eurocrypt smart cards.

I still have a Sony kv-fd1 16:9 TV with PalPlus. Very interesting video.

Another great video - there’s still so much to learn about legacy engineering standards. Thanks!

Excellent coverage of the subject. The history is extremely important. You get the Labguy seal of approval!

Well in Germany that transmitter problem probably wasn't to relevant, as the early 1990s saw a huge shift towards satellite in Germany. I think the first video I saw of PALplus was a demo tape... probably even down-scaled from HD as it looked spectacular. It was interspersed with a variety of test patterns. There was in fact regular programming well until the analog switch off, but encoders were no longer replaced. So if an encoder was broken that source would from then on only transmit letterboxed PAL (or of course 16:9 over DVB). What I've noticed in the late days of PALplus was that the quadrature filter for letterboxing wasn't very good. You could often see diagonal lines getting regularly spaced kinks in them. Sometimes stations would also put their PALplus encoder before the "bug inserter" resulting in broken signals. What was missing for PALplus in Germany were the receivers. Virtually no TV-set had one built-in, external decoders were insanely rare. I wouldn't be surprised if there were more D2-MAC receivers than PALplus just because for a while it seemed like the future would be HD-MAC and a D2-MAC receiver would be compatible. PALplus was always designed as an intermediate step. However from what I can gather, at least some modern TV chipsets employ a lot of the techniques coming out of PALplus. I have a (homemade) test signal generator with a 4,3MHz luma-burst and at least my 2010 Grundig TV was able to perfectly separate luma from chroma there. It's PAL decoding was done by a Mediastar (now Mediatek) chip"set", so that was nothing special. BTW if you ever want to do something about Teletext. I do have a little animation I made for showing at talks. It starts by showing a real decoded video signal. Then it shrinks the video and brows up the teletext lines, then showing each scan-line being translated into it's textual data.

I am really glad that there is this channel that deals with technology that has no practical application. Thank you so much!

Great video (Though I'm pretty certain PALPlus fully blanked the source lines 23 and 623 - the half lines - and used them for references + Line 23 also has a half line of WSS) so PAL Plus really delivered 574 lines, not 576, which means the letterbox is 430 not 432 lines from memory). Also the guy in the blue jumper and checked shirt at 7'39" in the old BBC Outside Broadcast scanner / van is my dad! Decoder SCART is almost certainly to feed out and back to an external descrambling box for Pay-TV. If PALPlus was used on satellite (or they though it would be) then it may have been aimed at pay-TV operators (or it may have needed to be integrated into that kind of set-up). I've read two reasons for VCR SCARTs - one was to be able to record the anamorphic decoded output to VHS (retaining a higher quality recording than the letterbox), the other was to allow you to record and replay PALPlus programmes and decode them from VHS (though the helper signal would have been near-useless after VHS chroma recording?). The TV output is presumably also RGB analogue - because of the joy of SCART so you get the benefit of ColourPlus? If you re-encoded to composite you'd have lost that? All the demos of PALplus I saw were pretty dreadful.

@mattstvbarn

5 ай бұрын

I wasn't able to get RGB out of it.

@stephenneal7373

5 ай бұрын

@vbarn How odd. I can't imagine the purpose of a PALplus decoder with all the ColourPlus stuff if it didn't decode to RGB. If as a manufacturer you're re-encoding to PAL for TV viewing you're killing the picture quality.

@mattstvbarn

5 ай бұрын

@@stephenneal7373 I've heard this model didn't do colourplus.

@Zcooger

5 ай бұрын

AFAIK Premiere Germany used to provide PAL+ shows scrambled with Nagravision Syster so it means these technologies were compatible. The decoder for Premiere could use single SCART cable between the TV or SAT receiver, same as Canal+ in France and Poland used.

An excellent video. Thanks for taking on this incredibly complicated technology. And hats off to those who engineered all this. I wonder if Techmoan will also do something on PalPlus? There must be a rubber belt in there somewhere....

I remember Channel 4 showing an edition of Fifteen To One (a quiz) whilst I was in the TV section of John Lewis department store. The picture on the one TV capable of decoding PalPlus was distractingly noisy, giving me the impression that you needed exceptionally clean reception to benefit.

Another thing Palplus had going against it was broadcasters wanting to use a compromise 14:9 letterbox on analog with true 16:9 reserved for digital. Edit: just after I wrote that you said it in the video lol

Nice video on pal standards 😊

How did the PalPlus signal work with color under VCRs? Remember that the color playback hetrodyne process produces a free running subcarrier against the signal H&V sync. And then the azimuth recording process also needed a field by field subcarrier phase swap as the head azimuth crosstalk cancellation was no good at the down converted chroma frequency. I also noted lack of any analog anti-aliasing or re-construction filters on those ADC and DAC chip. (unless they were SMD under the board). That right there is a serious image quality problem. I mean how much do a few small inductors and capacitors cost?

@mattstvbarn

5 ай бұрын

I don't know at present, but it sounds like an interesting thing to test

@altebander2767

5 ай бұрын

Well I don't think the re-construction filters were that important. After all the worst that could happen was that the video looks a bit "pixelated". All the signal frequencies are well below half the clock rate. In fact typically you sample composite video at 4 times the chroma subcarrier which gives you ample headroom.

@altebander2767

5 ай бұрын

I know there were some "VHS" recorders advertised to support PALplus. I think I actually have a PALplus recording standard consumer color under recording (Video 2000), but Video 2000 uses some trickery by averaging the chroma of lines for noise reduction. It might be that, for example U-Matic would just record it with reduced fidelity.

@stephenneal7373

5 ай бұрын

@@mattstvbarn Does the VCR SCART output a full-height anamorphic decoded picture (so you could archive the PALplus decoder output)?

@mattstvbarn

5 ай бұрын

@@stephenneal7373 from memory it does, yes

Very interesting video, i remember PALplus was quite popular in the Netherlands on public television channels. I remember seeing that test screen.

Wow what a complication, whilst I did see full letterboxing, and partial letterboxing on the analogue signals (Australia) I don't know if they ever tried this one. However I did hear of another PAL addition (and though that's what this video was), however I think it was called Super PAL, and offered better chroma resolution, however digital seems to have beaten them all to market.

A decoder, a device for decoding signals encoded by analog conditional access systems.

Fascinating video as always. Is there a way to get an anamorphic signal to letterbox on a 4:3 TV? It seems any active adapters seem to forget 4:3 / 16:9 was a thing and not let you set it

@altebander2767

5 ай бұрын

Well at least with SCART inputs you can use the 12 Volt signal that switches to the AV input and just put 5 Volts on it. Some newer 4:3 CRT-TVs will switch to 16:9 then.

@stephenneal7373

5 ай бұрын

My 1990s 4:3 Sony TVs had a menu or remote option to put them into letterbox, and respected the SCART Pin 8 4:3/16:9 status voltages. Some late era ones may also have respected Line 23 WSS.

Always wondered how random Channel 4 movies displayed with significantly higher resolution back in the day. Shame the BBC never adopted it.

I'd like to build a replica of a Philips PM5644 pattern generator that displays the date and time but I don't know how - but I'd like to try it on a Rasberry Pi and see if I can do it.

@mattstvbarn

5 ай бұрын

Better to crack on with it then no? I'm not going to do it for you.

Don't see any reason why people would criticise discussing innovative technologies of the past. If they don't like it, don't watch it! I found this video very interesting, thanks for taking the time and effort to make it.

@mattstvbarn

5 ай бұрын

There is nothing wrong with it of course, but doing so limits the size of the audience of the channel somewhat!

I find your reasoning at 2'00" - 2'34" a bit obscure. What you are trying to say is that at the time 16:9 content was to be delivered using full existing signal resolution (as opposed to letterboxing) for 16:9 TV-sets, anamorphic was not an option as current 4:3 TV's had no letterbox feature . Hence PALplus was created which is backwards compatible with all 4:3 TV's (showing letterbox format) and still use the full signal for 16:9 TV's. On a side note: letterbox format on 4:3 TV's had already be in use for widescreen movies, before pan & scan became the fashion. After the arrival of 16:9 TV-sets and before, besides and within PALplus letterbox came back. 16:9 TV's lacking PALplus or getting a plain letterbox signal simply upscaled the picture pushing the black bars of of the screen.

Encoding PAL (or any modulated colour video) with consumer grade circuits is generally a pretty poor idea. The outcome isn't the best. However just about every PAL TV supports RGB over SCART so that would have been a sensible option? Really don't see how that would have been necessarily worse than digital from DSP to display, given the output is a fundamentally analogue RGB CRT anyway.

@mattstvbarn

5 ай бұрын

The PALPlus decoder doesn't do RGB out.

I wonder what happens if you record a PALplus signal on VHS. Can it still be decoded afterwards? Were PALplus prerecorded VHS tapes available?

@Zcooger

5 ай бұрын

Mostly not as color-under recording scheme would degrade the helper signal a lot. However there are LD releases including Sony trinitron PAL+ demo disc which are found and captured using domesday decode method.

@JJVernig

3 ай бұрын

I had the same thought, and have probably some dutch and Belgian PalPlus on S-VHS. Maybe that has survived, but I don't have a decoder...