Hdtv??

[workshoppete]

Being as sky are bringing HDTV to our screens this Christmas via Sky sports....How about a HDTV topic.
Just a thought ....

 

[rolfw]

Been thinking about it, but a dedicated section may be a little quiet at the moment, very few people (apart from those in the industry and a few hobbyists) are talking about it. What I'll do is add it to the Tech Head forum, under the AV Discussion section.

I'd like to be proved wrong, but I believe that they have an uphill struggle on their hands to preach this gospel. ;)

 

[rolfw]

Thanks for the suggestion, have now adjusted the section heading to include HDTV and lets hope that it does catch on, certainly been impressed with what I've seen so far.

 

[workshoppete]

Well Good old Sky are going to throw Megabucks at it so it should arouse a bit of interest in the coming months. Having seen a few of the demo's at trade shows ,it is impressive on a big plasma screen. But as you say ...it remains to be seen if it will catch on .
Time will tell.

 

[rolfw]

If you have any specs on receivers etc, please feel free to post them in the section, ultimately it would be nice to do a FAQ on it.

 

[gameboy]

Is it not the case that pictures are not yet digital due to the fact that most TV can't handle it?

Do all the digital boxes not convert the signal to analogue before sending to the TV.

Some of the latest PC, LCD and Plasmas had digital inputs.

That would be better than present but not as good a HDTV?

Seem to remember a modification for the standard S*Y box to output digital and it cost a couple of grand.

I stand to be corrected - as the man said in the orthopedic shoes!

 

[PaulR]

Seem to remember a modification for the standard S*Y box to output digital and it cost a couple of grand.

This isn't true HD but simply getting the best out of the standard signal that $ly/BBC etc broadcast.

There was a company offering the very expensive route but there is a much cheaper way if you have a first generation $lyPlus box.

See http://www.irj-tech.com/ for further details of how to DIY.

PaulR

 

[spiney]

In fact, all digital receivers DO have digital outputs, usually that's the SCART socket.

But, it's also true most tv displays can't show the standard European (575 lines) full picture resolution, and therefore I agree HDTV seems a bit redundant (maybe a way for broadcasters to make more money). Although, at present, much material is actually recorded in 1050line format.

 

[PaulR]

Spiney

I have to disagree with you about the scart socket. This purely an analogue socket, for both video and audio. Even setting the option for RGB output still outputs in analaogue - althought superior to composite.

I thought the HD format was 1080 not 1050, or was that a slip of the keyboard? !

PaulR

 

[Llew]

Perhaps spiney means RGB is digital in the sense that the signals switch the CRT guns on and off during the scan to make up the colour picture ;)

Otherwise, as you say, all signals available from the scart are analogue, supplied by the MPEG decoder's D/A converter.

Llew

 

[workshoppete]

Maybe the reason for the big push is because when the likes of sky sport is blown up to a picture plasma/LCD size of 32 inches or more ,the picture becomes muddy and ragged,(and that's standing well back from the display!), emphasising the lack of fidelity compared to analogue. The HD format takes care of that (at a cost).
Maybe it will catch on in pubs,clubs and enthusiastic households but dont see Mr Average rushing in for a while yet.

 

[spiney]

nope, SCART is the digital output! At some point, the stream of 1s and 0s must be converted into a time varying voltage, to operate some type of display device, whatever that might be. Just as with digital audio, for operating an amplifier and loudspeaker. Otherwise, how on earth could you display the picture? What proceedure would turn the 1s and 0s into brightness and colour?

(Since this voltage is in incremental steps, and not infinitely variable, it is in fact a true digital output!).

Analogue output would normally refer to baseband composite PAL, or modulated UHF.

As for 1050/1080, what's 30 lines between friends?

 

[Llew]

nope, SCART is the digital output! At some point, the stream of 1s and 0s must be converted into a time varying voltage, to operate some type of display device, whatever that might be. Just as with digital audio, for operating an amplifier and loudspeaker. Otherwise, how on earth could you display the picture? What proceedure would turn the 1s and 0s into brightness and colour?

(Since this voltage is in incremental steps, and not infinitely variable, it is in fact a true digital output!).

The digital stream has already been converted before it appears at the scart - if you check the RGB outputs with a scope with the timebase running at line frequency you will see the amplitude of the R, G and B signals varying over the line period, e.g. the time it takes to scan the screen.

These will be fed to the RGB drive amplifiers to operate the CRT guns. Nothing to do with 1's and 0's at the scart output.

Llew

 

[spiney]

thanks, but I understand all the technology extremely well!

Point is, exactly what would count as a "digital output". You can certainly have a digital videostream, a la EBU standards, but you can't directly display it.

"It might be a plug to you, but it's a socket to me!"

(Rowan and Martin's laugh-in, NBC tv, circa 1968).

 

[PaulR]

A digital output is either there or it isn't. Either a certain voltage or not. Either a 1 or a 0.

When a digital signal is converted to an analogue signal it is an approximation of the original analogue signal and is composed of voltages at specific, very small, differences. No matter that it is a jagged voltage signal, it's still analogue.

Digital outputs, on the new generation of HD receivers and on the older receivers which have a digital audio output are simply a series of 1s and 0s at very high speed which are converted, by the display and audio amplifier respectively, into analogue video and sound respectively.

Now I know this is a simplification of a real world digital transmission with quadrature, and higher, modulation but the point still stands valid.

PaulR

 

[spiney]

(sigh) ........

To store any mpeg2 tv programme in original digital format (without conversion), you have to "lift" it out of the transport stream, then reformat for storage, which is what dedicated Freeview PVRs do (eg, Pace, Fusion, etc, PC cards use the native operating system). But, doing this requires decoding first. That's why the MPEG stream isn't generally made available, because "raw" it's useless!

The SCART usually gives the cleanest available signal, hence is effectively the "digital" output.

 

[Llew]

The SCART usually gives the cleanest available signal, hence is effectively the "digital" output.

I have to agree with you that putting digital in quotes allows a different interpretation of the signal source, even though it is still technically incorrect.

A shame you didn't do so in your first post. Would have saved any misunderstanding.

Llew

 

[Analoguesat]

:-topic

Only 3 HDTV licencees on the Ofcom list so far:

Artsworld HD
Discovery HD Theatre
Sky Sports HD.

 

[longreach]

With regards to HiDef TV you will need a Digital input on your monitor (HDMI jack or an HDCP-enabled DVI jack).



The first batch of HiDef receivers S*Y will ship may have component jacks this to accommodate existing monitors. After this the second batch they will be HDMI only, HDCP-DVI to HDMI converters are available. There will be normal outputs available but these will be downconverted so no HiDef.



Two standards will be used 720p and 1080i, the first one for sports and movies etc the latter for documentary and news etc. The broadcaster will determine these modes as they are in control of the receiver.



I have just had a demonstration of High Definition on Panasonic Plasma TH42PV500CAB the source is a Japanese Hi-vision receiver fed HiDef pictures from a hard drive using component inputs on the plasma. The images were simply stunning there were no colours bleed no stepping on diagonal lines the reinforcement in imagery was breathtaking. The demo consisted of two champagne glasses with champagne bubbles rising to the top I could see every bubble that made every bubble up as they rose to the top the quality was simply stunning it’s a though I just opened my eye’s for the first time wow!



Then we returned to Animal plant on S*y digital the picture simply pure shite worse than Long play VHS, if I was paying for that I would be demanding my money back, I’m now having trouble watching terrestrial pictures and I have a improved definition television made by Sony.



They should scrap Fr**vi*w and change it over to HiDef .



High Definition will come via the USA on HD-DVD import, programmes are all ready made in HiDef, Once this takes effect broadcasters will have no choice to launch HiDef along with Dolby Digitals and DTS in the UK as viewer number will diminish, revenues will be down, this could be the end of Tv as we know it.

:-topic

Only 3 HDTV licencees on the Ofcom list so far:

Artsworld HD
Discovery HD Theatre
Sky Sports HD.

 

[spiney]

the post just above also appeared in the other HDTV thread, and as i said there, it is extremely confused. Somebody has obviously seen a prototype HDTV plasma screen demo, fair enough, but otherwise got hoodwinked by the salesman.

Regarding SCART, did you really think I don't know what comes out of it? You can't simply have the MPEG data stream "output", it's useless, and the SCART output is effectively the nearest thing to a "digital" output.