Re: Will F1 be on BBC HD?

Ian Rawlings wrote:

On 2009-02-27, Bigbird <bigbird.usenetNOSPAM@xxxxxxxxx> wrote:

You don't? No I guess you get one line scan per line.

You don't even get that normally other than on professionally adjusted
video monitors used in video editing. That's one reason why modern
CRTs use screen-height vertical stripes of RGB material rather than
the older type which used small vertical stripes, it mostly removes
the issues of lining up the picture vertically.

Try this. Upscale an 8 pixel by 8 pixel chessboard to 12 pixels by
12 pixels. What size squares do you have?

An SD signal does not match the resolution of pretty much any SD
display, so you have to scale the incoming video to fit the display
anyway. A DVB signal is anything from 544x576 to 720x576 for UK-spec
DVB, and a DVD is anything from 352x576 to 720x576. LCD/plasma
displays are pretty much always square-pixel displays, but video
pixels are not square, even for 4:3 displays so you need to scale
the images whatever display you have.

You miss immediately that it is things like this that cause a problem
taking an SD source straight to an HD TV. As you point out the ratio
for TV is 1:1.094. On a CRT this will look fine. On an HDTV you
immediately have to stretch or squish the picture.

You are back to the chess board problem. Having more pixels available
alone does not make the picture better if the source must be
interpolated to make it fit or to display the correct aspect ratio.

(My word the number of people watching most of their programs in the
wrong aspect ratio - they seem to get used to it but it really annoying
as a visitor, mind you it seems alomost unavoidable on a lot of TVs
since they introduced "Digital" both CRT and HD)

The more pixels you have as the
target resolution, the better the scaling result will be.

CRTs have discrete stripes vertically so break the picture up into a
given number of blocks, and the number used is widely varied and the
TV adjustments make sure the pixels in an incoming pixel-based signal
won't match them as overscan, flyback, blanking, porches and all the
other variables vary from TV to TV and even depend on how warm the
things are.

All this is before you start getting into visible pixels versus
non-visible pixels in the video specs, e.g. a 720x576 DVB signal will
have 702x576 pictures that are actively part of the signal, the
missing pixels are in the spec to cater for analogue displays.

And I won't even go into US-sourced video, where the resolutions are
even further away from the notional 768x576 display that people tend
to think we have (it's a square-pixel equivalent of 720x576
video-pixels -- they're not square remember).

As for analogue signal, it doesn't have a horizontal resolution, only
vertical, it's split into discrete lines but each line is sent as an
analogue wave with no discrete separation and is then mapped onto
either RGB stripes on a CRT or square-pixels on a pixel-based display
like plasma or LCD.

You definately need to get yourself down to specsaver.

You need to read up a little more on video standards and how TVs work.


All the reading you do will not change the result you see on screen. It
may tire your eyes though.

I haven't been looking recently but I have seen no end of HD TV's
(including one I bought and returned) displaying far worse SD
pictures than just about any CRT.

Yep, but comparing a *** and/or poorly adjusted HD display with a
reasonable SD display is not comparing HD with SD, it's comparing a
*** display with a good display. Most displays I've seen come out of
the box with terrible settings, sharpening turned up, contrast turned
up and so on, to give punchy pictures because that's what most people
seem to like. A good HD display is good, a *** HD display is ***.
The first step is to get a good display setup kit and sort the display
out and turn off most of the "enhancement" settings that are enabled
by default and turn down the contrast, then start playing. Ideally
the contrast (better known as "white level") and brightness (better
known as "black level") should be varied depending on the room
lighting but I tend not to bother as I'm not that fussy.


That doesn't even address most of the visual artifacts...and with all
that you still can't see why people think what they do?

I dumped a Loewe Cantus CRT and replaced it with a decent-spec Sony
LCD (I'd have gone for plasma but it's mostly for computer use) and
the Cantus can't match the Sony at all.

Watching Blade Runner for the millionth time but this time on HD-DVD
was like seeing it for the first time, ditto 2001.

That will mostly be a re-mastering of the source then. I have
Bladerunner on DVD and the source is pretty poor no matter what you
watch it on.

....but now you are wondering way off your original track that I
questioned and that is whether a SD source will always look better on
HD regardless. Fact is it won't/doesn't.

On HD you often
get different shots than you did on SD as wide scene shots with lots
of detail become possible and are returned to the cut after being
removed from DVD due to the pictures looking crap on SD. There's
quite a few of these in 2001 on HD-DVD, I kept seeing scenes for the
first time as they'd been in the cinematic release but not on the
various DVD releases (about 2 or 3 different ones) I'd seen before.
Cartoon-based material really shows it up dramatically, e.g. Corpse
Bride. Older films that have had bad conversions sometimes look
pretty much identical, you can just see the film grain clearer!

I think that broadcast HD is only 720p, but having watched some sports
matches at a local hifi shop on BBC HD Preview, it was much better
than their SD displays, 1080p is even better still but I don't think
that's going to be coming over the air.

So do you live in the suburbs or downtown Stupidsville? ;)

There are nutters everywhere! People like to try and paint themselves
as having some knowledge that puts themselves above everyone else and
disparage common knowledge, e.g. 9/11 was the american government's
doing, UFOs are aliens, HD is "all hype" and so on,

I don't think anyone here said that.

The posts you replied to simply related that they were fed up with
people complaining about the poor picture on their HD TVs.

Now you should be telling the "willy wavers" what a good picture they
have compared to CRT not trying to tell those that have not "upgraded"
and aren't complaining that the picture they are content with is ***.

but often it's
their own inability to comprehend the subject that's the issue and not
them being cleverer than the rest of the population like they think.

There are a lot of disappointing HD displays out there, but that's not
down to the picture resolution, it's just those individual displays
being ***, or badly adjusted, or fed crap sources.

....or unable to display a given SD source as well as the average CRT
out of the box.

There are a lot
of *** SD displays too for the same reasons.

Yup, but the consequences for the picture appear to be far less of a
problem.

I'm only going by what I see at my friends and families homes, many of
whom have plumped for good brandname huge LCD full HD TVs that I have
sat in front of and what smudged blurry images compared to the apparent
crystal clarity on the inherited no name CRT I am haging on to for now.

No doubt this is what is at the root of the OPs problem so perhaps some
advice to him on how to adjust his TV correctly may not go amiss.

--
Bigbird
.

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