Confusion over high-definition TV

[Steve]

"But it's HDTV; it's higher resolution than real life! - Fry, Futurama

Buying an HD TV doesn't mean you can watch HDTV on it, reports the BBC.

There are 74 different devices that are being sold as HD but are not HD-ready, according to Alexander Oudendijk, senior vice president of marketing for satellite giant Astra.

They may be fantastic quality TVs, but many do not have adaptors in them - called DVI or HDMI (High-Definition Multimedia Interface) connectors - which let the set handle the higher resolution digital images.

[The story]

[Rave]

The average guy in the street hasn't really got a hope in hell, I'm a computer geek and a TV/ home cinema geek, and it took me ages to figure it all out.

I'm still not quite sure what happens when you feed a 720p signal into a screen with a resolution of 1366x768....does the scaling knacker the quality like it does when you feed a computer TFT a non-native signal?

[rajagra]

There is yet another problem. When Sky starts transmitting HDTV it will only work with a display containing an appropriate content-protection system! Having DVI or HDMI is not enough. Aaaargh!

[iranu]

The average guy in the street hasn't really got a hope in hell... it took me ages to figure it all out.

ditto.

I also don't believe that just because a telly has an HDMI/DVI input that it is truely HDTV compatible. e.g. a 848x480 will accept and process/down scale the signal to give you a (admittedly better) picture but it is NOT HD quality. You need a higher res panel.

Rave - I think this answers your question. So I do think there will be scaling from 720 to 768 by the telly involved. Search the link below for more info (on lines/scaling/progressive/interlaced signals) if you wish to hurt your brain.

The best place on the net for these issues is avforums-HDTV

I don't normally link to other forums (i.e. takes readers/revenue away from Hexus) but for peoples general information I thought this would be useful as it's dedicated to HDTV.

[scottyman]

different pixel aspect ratios are the killer in this arena. I've been playing with HD for a good couple of years now - but the content protection system was only ratified a little while ago (not by us)
I think the guy who wrote the article above is a yank who hasn't quite got his head around PAL (Phase Alternating Lines) which interlace (hence the I) the two different fields. PAL (in broadcast) uses two fields (upper and lower) to represent a frame - we broadcast 25fps, made up of 50 fields (50Hz signal - matches power). Sky will interlace while compressing the image prior to muxing the signal for the transponder. (missing out a few rather large segments here guys)
Analogue broadcasts don't bother with this, as there's no bandwidth restriction (well - there isn't for sky - just means they don't have to have all that many sat's and transponders in orbit) Either way - HD is going to be run highly compressed interlaced signals.
whereas you'd buy a 3mb datastream from sky for broadcast (good, midrange mpg2 quality) you'll now have to go to 7 - much higher data rate for much "larger" imags, compressed at a slightly lower rate.
Progressive basically uses adaptive rate control to "fill in teh blanks" wher it should de-interlace the fields, determine what should go between pairs of fields, fill int eh gaps then re-interlace them. smoother motion to match the capabilities of the screen.
most of the current HDMI and DVI compliant screens should support this no problem, but will have to be run through an AV amp which will allow it to be processed downstream. usually a better solution, and one that's been agreed to by most content providers to allow early adopters to get access to the media they're rightfully able to see.

[rajagra]

Also HD-DVD has been formally released at CES, it sounds great, and looks more likely to take off quickly than Blu-Ray (or Beta-Ray as some cruel wag called it.)
One fly in the ointment - someone asked the HD-DVD reperesentatives if it would follow the same regional encoding practice as DVD does, and they were genuinely baffled as if they didn't know DVD was used outside of the U.S.

[scottyman]

ROFL! love it.
had exactly the same situation at NAB a couple of years ago - these were broadcast technology companies who didn't have an excuse.
one classic (from one of my suppliers) ... me: "what's up with your PAL D1 support?" (i.e uncompressed pal - 50Mbit per second) them: "well, it works perfectly over here" ... me: "but have you tested with PAL equipment?" them: "well, PAL isn't much of a requirement - NTSC is used in more countries" .... right... so most of the countries in the world don't count? unless they're the US, and matey got confused and thought that each different state in the US represented a different country.
tuned out to be their color combing (turned on by default for NTSC) showing as disabled in their software - but wasn't.
you should've seen the guys from germany getting ready to slap him silly. It's very much a US versus rest of the world experience there. the yanks tend to think the BBC is a quaint little backwater tv network LOL

[Rave]

Yeah well there's another question- are we going to continue with the US and Japan using 60FPS formats and Europe/rest of world using 50FPS? If not, why has the opportunity not been taken to standardise since we're going to digital transmission?