BBC 1 HD Picture Quality - Any views?
 

On Sat, 06 Nov 2010 09:16:52 +0000, Mark Carver
wrote:

Actually none of this should be required, it's rather sad that whether a
programme is in HD or SD needs to be flagged at all, it should be bloody
obvious when watching it !

Hurrah!!

--
Alan White
Mozilla Firefox and Forte Agent.
Twenty-eight miles NW of Glasgow, overlooking Lochs Long and Goil in Argyll, Scotland.
Webcam and weather:- http://windycroft.co.uk/weather

BBC 1 HD Picture Quality - Any views?
 

On Nov 6, 12:15*am, "j r powell" wrote:
I realise that PAL colour was lossy, but the replacement SD digital
transmissions have colour space limitations as well - it doesn't even come
close to true RGB, and imho "true PAL" beat it by a considerable margin as
well.

Sorry, I don't understand that. All modern PAL transmissions are
derived from Rec.601 component video (YCbCr) which has precisely the
same colour space characteristics as DTT transmissions. So when
watching DTT you're effectively seeing the colour signal that went
into the PAL encoder, except with a higher bandwidth (around 3 MHz
rather than about 1.5 MHz). Neglecting MPEG compression artefacts
(which aren't relevant to colour space) it's impossible for analogue
PAL chroma to "beat" DTT chroma.

As for the PAL combing artefacts, they are considerably minimised in
real-world scenes on quality "true PAL" sources, because these natural
scenes tend not to contain sharp colour transitions.

I didn't mention combing, I was talking about cross-colour. Cross-
colour artefacts are often terrible in "real world" scenes, especially
if you consider check jackets and fences 'real world'!

What
you *did* see were vibrant colours, perfect motion tracking with no added
blur or loss of subtle movements,

Digital transmissions (DTT or DSat) don't suffer from any less vibrant
colours (see above). Any motion issues or blur arise only from MPEG
coding issues, and are negligible when the material isn't stressing
the encoder (ignoring, of course, issues quite unrelated to digital
transmission like the Channel 4 problems discussed in a different
thread).

Whichever analogue transmitter you're watching, remember that any
non-progressive/pulldown content shown in 14:9 or 16:9 letterbox will have
been processed through an ARC which applies a lossy
deinterlace-rescale-reinterlace process

Now you seem to be saying that PAL can be inferior to DTT, which I
thought was the opposite to the argument you were trying to make?
Anyway, the loss from an ARC is minimal - what there is comes mostly
from the deinterlacing; the scaling and re-interlacing aren't
significantly lossy (additional to the fundamental reduction in
vertical bandwidth).

Anyway, congrats on successfuly changing the topic from "BBC HD bitrates are
too low" to "digital is better than analogue so shut-it" without answering
any of the points I raised in my last post.

It was *you* who raised the issue of analogue versus digital, not me!
Anything I failed to answer was because I didn't feel qualified to do
so. For example I don't know what research has been carried out on
whether the relationship between resolution and perceived quality is
linear. I don't know whether the bitrates used on SD and HD result in
similar degrees of degradation, or whether any decisions were made on
that basis.

You'd make a good puppet politician.

I am an engineer, and like all good engineers I try to steer clear of
politics and commercial issues. I would not want to be in the shoes
of somebody like Andy Quested who has to concern himself with both.

Richard.
http://www.rtrussell.co.uk/

BBC 1 HD Picture Quality - Any views?
 

Richard Russell wrote:

I am an engineer, and like all good engineers I try to steer clear of
politics and commercial issues. I would not want to be in the shoes
of somebody like Andy Quested who has to concern himself with both.

Don't waste your time on him, Richard. Most of us have kill-filed him
because of his frequent outbursts of offensive behaviour.

SteveT

BBC 1 HD Picture Quality - Any views?
 

On Nov 6, 11:11*am, Steve Thackery wrote:
Richard Russell wrote:
I am an engineer, and like all good engineers I try to steer clear of
politics and commercial issues. *I would not want to be in the shoes
of somebody like Andy Quested who has to concern himself with both.

Don't waste your time on him, Richard. *Most of us have kill-filed him
because of his frequent outbursts of offensive behaviour.

Who? Andy Quested??? ;-)

Richard.
http://www.rtrussell.co.uk/

BBC 1 HD Picture Quality - Any views?
 

On Fri, 5 Nov 2010 08:26:03 -0700 (PDT), Richard Russell
wrote:

On Nov 5, 2:47*pm, Geoff Berrow wrote:
When colour TV started (and yes, I remember) studio stuff and new
material was always in colour.

Your memory is faulty.

No question about that grin I never said I remembered it
accurately. Would have been damned difficult anyway as we only had a
black and white TV, ;-)

When colour first started on BBC2 (1967)
plenty of programmes were still made in black and white because not
all the studios had been converted to colour. Here are some dates:

TC6 converted to colour in 1967
TC8 converted to colour in 1968
TC1 converted to colour in 1968
TC3 converted to colour in 1969
TC4 converted to colour in 1970
TC5 converted to colour in 1973

I don't think it's unreasonable to
expect studio stuff and new material to be in HD.

I think it's totally unreasonable. Who is going to pay for the
studios to be converted and re-equipped?

Well you mention the time factor. The BBC HD channel has been going
now since May 2006. I think that's plenty of time to re-equip the
main studios that are in constant use.

Who is going to pay for HD
CGI on programmes like Merlin (time as well as money)?

Have you got a cite for that? Is there really that much of a cost
difference in rendering in HD as opposed to SD? And as someone else
has said, the costs could be recouped in increased marketability.

If it took
something like 6 years to convert the BBC studios from B&W to colour,
it seems perfectly reasonable for it to take a similar time to convert
them to HD.

Well I can't comment on whether the change from b/w to colour is
comparable to the change from SD to HD. Yes, I would agree that the
change would take a long time to complete, I don't have an argument
for that. But I would still have expected the main London studios to
have been converted after 4 years and certainly before they roll out a
BBC1 HD channel.
--
Geoff Berrow (Put thecat out to email)
It's only Usenet, no one dies.
My opinions, not the committee's, mine.
Simple RFDs www.4theweb.co.uk/rfdmaker

BBC 1 HD Picture Quality - Any views?
 

On Nov 6, 11:35*am, Geoff Berrow wrote:
Have you got a cite for that? Is there really that much of a cost
difference in rendering in HD as opposed to SD? *And as someone else
has said, the costs could be recouped in increased marketability.

There's a comment on Digital Spy he

http://www.digitalspy.co.uk/forums/s...php?p=27517578

"The company that does the CGI will charge a broadcaster more for HD
then they would for SD because it requires a far higher skill set and
hardware platform to produce not to mention a much longer time scale.
It basically comes down to billable man hours and the competition
between graphics studios all of which can do TV standard SD against
far fewer who can do TV even theatrical HD".

Danielle Nagler's comments on Merlin are he

http://www.bbc.co.uk/blogs/bbcintern...orks_best.html

"... unfortunately, Merlin will not be on BBC HD. Sometimes, for a
whole variety of reasons, the production team decides that it doesn't
want to use the format. Those of us on BBC HD felt that Merlin was a
show that we should aim to deliver in high definition, but in the end
it was shot in Super 16."

Richard.
http://www.rtrussell.co.uk/

BBC 1 HD Picture Quality - Any views?
 

In article ,
Geoff Berrow wrote:


Well you mention the time factor. The BBC HD channel has been going
now since May 2006. I think that's plenty of time to re-equip the
main studios that are in constant use.

Plenty of time - perhaps - but it's more a question of money, I suspect.

--
From KT24

Using a RISC OS computer running v5.16

BBC 1 HD Picture Quality - Any views?
 

Richard Russell wrote:

Who? Andy Quested??? ;-)

j r powell.

SteveT

BBC 1 HD Picture Quality - Any views?
 

Oh, poop - I didn't notice the smiley!!

SteveT

BBC 1 HD Picture Quality - Any views?
 

"Richard Russell" wrote in message
...

Sorry, I don't understand that. All modern PAL transmissions are
derived from Rec.601 component video (YCbCr) which has precisely the
same colour space characteristics as DTT transmissions.

So when
watching DTT you're effectively seeing the colour signal that went
into the PAL encoder, except with a higher bandwidth (around 3 MHz
rather than about 1.5 MHz). Neglecting MPEG compression artefacts
(which aren't relevant to colour space) it's impossible for analogue
PAL chroma to "beat" DTT chroma.

The point I am making however, is that unlike "true RGB", SD digital TV
before it's even been MPEG comprssed still applies a reduction in chroma
bandwidth relative to the luma - Rec.601 uses 4:2:2 chroma subsampling, so
compared to the monochrome component, the colour components only have half
the number of horizontal samples.
Remember this issue was only raised when you siezed upon PAL's lossy colour
compression as an excuse to say "analogue transmissions aren't
uncompressed".
Like it or not, the fact is that analogue luma (within its allocated
bandwidth) was completely uncompressed, whereas current digital
transmissions do not even come close to achieving this.
The human eye is more sensitive to brightness (and motion) detail than it is
to colour detail, which is why PAL produced satisfactory results, and also
why broadcasters feel 4:2:2 colour subsampling is acceptable in the present
day (not that anyone seems to care about quality anymore of course).

It's also misleading to say "DTT colour has a higher bandwidth of 3MHz",
because after it's been through a low bitrate MPEG mush most of the extra
information will have been lost anyway.


I didn't mention combing, I was talking about cross-colour. Cross-
colour artefacts are often terrible in "real world" scenes, especially
if you consider check jackets and fences 'real world'!

And on digital, check jackets et al are ravaged by something akin to
interlace twitter, seemingly occuring as the pattern edges jump between set
sample points, causing them to exhibit a flickering effect on CRT displays
which is far more noticible than PAL combing or cross-colour.


Digital transmissions (DTT or DSat) don't suffer from any less vibrant
colours (see above). Any motion issues or blur arise only from MPEG
coding issues, and are negligible when the material isn't stressing
the encoder

You can repeat your mantra of "MPEG issues are negligible" as many times as
you like, but the fact that I and many others disagree with you ought to
tell you something :P


Whichever analogue transmitter you're watching, remember that any
non-progressive/pulldown content shown in 14:9 or 16:9 letterbox will
have
been processed through an ARC which applies a lossy
deinterlace-rescale-reinterlace process

Now you seem to be saying that PAL can be inferior to DTT, which I
thought was the opposite to the argument you were trying to make?

Nice try. You'll notice I said "true PAL" in my last post - PAL from camera
to screen in other words. I also mentioned the fact that modern-day PAL
transmissions are derived from lossy digital sources, so they should not be
used as a point of reference and therefore have no relevance to this
discussion.


Anyway, the loss from an ARC is minimal - what there is comes mostly
from the deinterlacing; the scaling and re-interlacing aren't
significantly lossy (additional to the fundamental reduction in
vertical bandwidth).

The ARCs are lossy imo. I remember seeing ARC'd 14:9 content on BBC in
1997/8 before Winter Hill's analogue feeds were messed up completely; the
picture was noticibly more blurry on ARC'd content, and the motion tracking
was unnatural, compared to native 4:3.



Anyway, congrats on successfuly changing the topic from "BBC HD bitrates
are
too low" to "digital is better than analogue so shut-it" without
answering
any of the points I raised in my last post.

It was *you* who raised the issue of analogue versus digital, not me!
Anything I failed to answer was because I didn't feel qualified to do
so. For example I don't know what research has been carried out on
whether the relationship between resolution and perceived quality is
linear. I don't know whether the bitrates used on SD and HD result in
similar degrees of degradation, or whether any decisions were made on
that basis.

Okay, as long as we know.

I notice you smiled at Steve Thickery when he insulted me by the way, so
perhaps you's prefer to continue this discussion with him. You'll find he's
a big-headed anorak-type who, despite all his big talk, can barely even wire
an electrical plug. Like so many of his ilk however, he's good at being rude
and sneery, and uses this skill to gain whatever undeserved respect he can
from shallow people who don't know any better.

jamie.
--