Digital TV: the picture really is horrible!
 

On Aug 29, 1:55 pm, "Graham Harvest" wrote:

Do broadcasters still put a line of colour bars in the vertical interval?
I'm sure they all used to do this last time I checked (early 90's) and often
had a 2T pulse too.

No colour bars, you're thinking of the first few active picture lines
on Test Card F ?
However there is ISTR a linearity staircase, and 2T pulse and bar. UK
standard signal, carried on lines 19/332 and 20/333 I think ?

Only on analogue, not via DVB where they would have no relevance of
course.

Digital TV: the picture really is horrible!
 

In article .com,
scribeth
thus
On 28 Aug, 22:16, Paul Ratcliffe
wrote:
On Tue, 28 Aug 2007 03:19:53 -0700,

wrote:
However, Dance X... isn't the picture quality shocking? It seems
~5Mbps MPEG-2 just can't cope with flashing lights, fast movement,
detail and smooth gradients on screen at the same time etc.

You are surprised?

That the technology can't cope at that bitrate? No. That someone tries
to broadcast that content at that bitrate? Well, yes. Even now, I find
it unbelievable. I'm watching on a nice CRT - goodness knows how bad
it looks on most modern flat panels.

It would be interesting to compare the raw uncompressed version with
what reaches the home. In fact, I wish someone would force some BBC
execs to sit down and watch this comparison to realise what a problem
they have.

It looks great on a 2" screen though. What's yer problem?
Why don't you get the hi-def version if you want qwality?

I'm sure that's where we're heading. The main problem with that is
that lots of content won't be on the HD channel, leaving the
increasingly bitstarved SD channel as the only source.

If the BBC said "we'll simulcast all our channels in HD on DSat and
leave DTT for portable TVs" that would be fine. Unfortunately, it has
as much chance of happening as "we'll simulcast all our radio stations
in high bitrates on DSat, leaving DAB for portable radios".



In fact that would probably be the best way to go, high definition radio
and TV on satellite for fixed home consumption, and the more compromised
product for mobile and portable use...
--
Tony Sayer

Digital TV: the picture really is horrible!
 

tony sayer wrote:

In fact that would probably be the best way to go, high definition radio
and TV on satellite for fixed home consumption, and the more compromised
product for mobile and portable use...

Sssshhhhhhh!!!!.... The ex-media students running the beeb commonly use
google for research about technology that confuses them.

Ye don't wanna give them these ideas....

--
Adrian C

Digital TV: the picture really is horrible!
 

On Aug 29, 4:29 pm, Adrian C wrote:

Sssshhhhhhh!!!!.... The ex-media students running the beeb commonly use
google for research about technology that confuses them.

Ye don't wanna give them these ideas....

As long as no one posts any ideas in 'text speak' we should be OK !

Digital TV: the picture really is horrible!
 

Digital TV: the picture really is horrible!
 

On 29 Aug, 23:41, (Peter Hayes) wrote:
wrote:
I've been too busy to watch TV recently, so maybe I'd forgotten how
bad it could look, but...

I had chance to catch the last episode of Mountain on Sunday night,
and saw some of Dance X (?) the night before.

I enjoyed Mountain. Not too much distracting "filmic effect" (only on
a few shots), and only the MPEG encoding of moving fine details let it
down. Great programme.

However, Dance X... isn't the picture quality shocking? It seems
~5Mbps MPEG-2 just can't cope with flashing lights, fast movement,
detail and smooth gradients on screen at the same time etc.

In the PAL days, even in "component" studios, people monitored a
composite PAL version to see what it would look like at home. That
way, they could avoid including fine detail that was simply going to
be lost in cross-colour artefacts.

Or the strobing sports jacket.

Yet now, in these "MPEG-2" days, no attempt is made to avoid content
that stands no chance of surviving MPEG-2 encoding.

Since it looks fine on an analogue PAL screen why should a director feel
constrained because of the defects of one segment of the transmission
chain? I can just see his reaction to being told he can't now shoot the
way he did ten years ago "because the digital transmission chain can't
cope".

The answer isn't to impose silly restrictions on directors but to
improve the digital transmission chain. Improvements won't be made by
curtailing throughput, but by insisting that what was possible yesterday
must be made possible tomorrow. The alternative eventually becomes VHS
quality all round, eg ITV3/4.

I agree entirely, but I think the chances of digital SD picture
quality improving are about zero. If anything, I predict a continued
downward trend. Analogue SD has five years left at most, and is a
minority viewing platform on main sets.

So, producers et al will continue to create pictures which no one
outside the studio can ever appreciate?

Mind you, it should help push HD, if it stays at sensibly high
bitrates.

Cheers,
David.

Digital TV: the picture really is horrible!
 

Digital TV: the picture really is horrible!
 

One part of the digital chain that needs improvement is the quality of
most receivers. Freeview quality can be excellent, especially
downconverted HD, but Judging by what I see in the likes of Curry's the
receivers the public are buying are complete rubbish.


I should give what you wrote there some more thought;!...

So, producers et al will continue to create pictures which no one
outside the studio can ever appreciate?

But when they see their product destroyed in transmission they might
start asking embarassing questions. That's one way to force progress,
unless you are willing to surrender all policy making to bean counters.

Mind you, it should help push HD, if it stays at sensibly high
bitrates.

And comes down substantially in price.

Peter

--
Tony Sayer

Digital TV: the picture really is horrible!
 

On Aug 30, 11:58 am, (Peter Hayes) wrote:

One part of the digital chain that needs improvement is the quality of
most receivers. Freeview quality can be excellent, especially
downconverted HD, but Judging by what I see in the likes of Curry's the
receivers the public are buying are complete rubbish.

I'm not sure. Yes, 20 quid DTT boxes lock up, get hot, have crappy
GUIs etc, but I've not seen any dramatic differences in the basic
picture quality, between those and 100+ quid boxes ? With MPEG the
clever bits are done by the encoder, not the decoder, so in short
quality improvements can only really be achieved (and they have been
over the last 10/15 years) by improving the encoders. The only element
where the picture quality can suffer in a DTT box is after the D-A
converter, and of course the interface to the display device.

Digital TV: the picture really is horrible!
 

tony sayer wrote:

One part of the digital chain that needs improvement is the quality of
most receivers. Freeview quality can be excellent, especially
downconverted HD, but Judging by what I see in the likes of Curry's the
receivers the public are buying are complete rubbish.


I should give what you wrote there some more thought;!...

Freeview quality can be excellent, see the Reporting Scotland thread,
but if some content, "flashing lights, fast movement, detail and smooth
gradients on screen at the same time etc.", to quote the OP, fails, then
there's room for improvement.

That doesn't excuse manufacturers selling receivers that are, frankly,
junk.

Peter