BBC HD vs ITV1 HD

On Sat, 02 May 2009 18:02:20 +0100, Jerry
wrote:

Wouldn't it be nice for the BBC to ask the UK public if they would
actually mind if *their* test charts were stolen if it meant that the
UK public (who after all paid for it in the first place [1]) have the
ability to set their TV's up correctly and at any time?...

To ensure best value for the licence fee payer, the BBC has a duty to
do whatever it wants to.

--

On Sat, 02 May 2009 13:24:11 +0100, Richard Lamont
wrote:

With the improved spatial resolution of HD, maybe the poor temporal
resolution of 24p/25p becomes more noticeable. That's my impression from
watching films on Blu-ray.

Sony seem to be making a big deal of their 200hz Bravia displays at
the moment - but in some ways it's a shame that they'll almost always
have to spend their time trying to temporally deinterlace material
shot at much lower frame rates.
--

In article , SpamTrapSeeSig
writes
In article
.co.uk.invalid, Alan
Pemberton writes
Actually the camera captures a different *1/25* of each second during
each field. That's what makes the movement look so smooth, becasue the
fields overlap in time.

Ooh er, doc!

Doesn't that rather depend on the application of a "shutter", or
otherwise? I guess they used to, but nowadays? It's unusual for me to
work at shutter speeds below s/100. The camera doesn't have a physical
shutter, I know, but will achieve crisper slowmo at higher shutter speeds.

I'm sure that 'shutters' came into general use with CCD sensors in the
mid-1980s, but they're pervasive now. So, for any shutter speed over
s/50, isn't it reasonable to assume each field is without overlap?

They effectively came in much earlier than that, with the original EMI
camera tubes in 1934, although nothing like the extremely short shutters
of recent times, which is what most people object to.

Whilst the common explanation of interlace assumes that the lines were
read off the photocathode in an odd and even field sequence, and that is
certainly true, what is generally not understood is that all of the
charge was read off the photocathode in each field. So no charge
integrated during one field was available to be read out on the next.
The image was effectively shuttered at field rate, not frame rate, by
the tube. The spatial interlace simply oversampled the electron beam
spot size and lateral drift on the photocathode.

Indeed, early CCDs used a similar approach to interlacing, with the
charge under two gates combined in different phases in sequential
fields, thus achieving full vertical resolution with interlace although
only having adequate gates for half as many progressive lines.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

On May 2, 9:58*pm, Java Jive wrote:
I don't see how buffering as I've described it can in any way be
described as a form of deinterlacing. *It doesn't change the video
content or its change rate, deinterlacing changes both the video
content and its change rate.

No, you're quite right. I misunderstood your definition at first,
thinking you meant that it waited until both fields had been
received.

L

In article , jamie powell
writes

"Louis Barfe's IbMePdErRoIoAmL" wrote in
message ...

Each field represents a different part of that moment in time, though.
Although there is no actual movement within the frame, there is a
difference between the two fields that must be resolved.

The "no actual movement within the frame" is what the TV uses to activate
its pulldown detection.

So how does the TV discriminate between real motion in a small part of
the frame (couple of players on the pitch move between fields) and
spatial differences where the image of some objects in one field are
spatially different from the other field?

What if there is no motion in the image - does the TV get confused after
a while and decide it isn't interlaced after all? ;-)

How does it handle the difference between spatial differences in the
fields, motion differences and noise on old video recordings?

I don't think LCD panels are that smart.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

In message , Kennedy McEwen
writes

Whilst the common explanation of interlace assumes that the lines were
read off the photocathode in an odd and even field sequence, and that
is certainly true, what is generally not understood is that all of the
charge was read off the photocathode in each field.

Surely if what you say is true, there would have been no point in camera
manufacturers developing ACT circuitry, as the targets would have had no
residual charge at the end of each field?
--
If one person has delusions, we call them psychotic. If, however, 1.5 billion
people have delusions we must apparently call them a religious group, and
respect their delusionary state.

In message , Kennedy McEwen
writes
In article , jamie powell
writes

"Louis Barfe's IbMePdErRoIoAmL" wrote in
message ...

Each field represents a different part of that moment in time, though.
Although there is no actual movement within the frame, there is a
difference between the two fields that must be resolved.

The "no actual movement within the frame" is what the TV uses to activate
its pulldown detection.

So how does the TV discriminate between real motion in a small part of
the frame (couple of players on the pitch move between fields) and
spatial differences where the image of some objects in one field are
spatially different from the other field?

What if there is no motion in the image - does the TV get confused
after a while and decide it isn't interlaced after all? ;-)

How does it handle the difference between spatial differences in the
fields, motion differences and noise on old video recordings?

I don't think LCD panels are that smart.

They're incredibly stupid - even this one

http://www.sony.co.uk/biz/view/ShowP...d=35F166739819
E82B861D0175514CB62D?product=BVM-L230&pageType=Overview&category=BVM&site
=biz_en_GB

at more than 1o0k per unit - I don't imagine that sub 1k telly will be
any more intelligent

--
What sort of idiot buys into homeopathy - well the sick and the vulnerable,
those driven to despair by sleeplessness and pain, the 15% of people with lower
IQs, the gullible and naive, passive people who are easily bullied and cajoled.
young and inexperienced people. The mentally ill, and the easily manipulated.

In article , Tony Quinn
writes
In message , Kennedy McEwen
writes

Whilst the common explanation of interlace assumes that the lines were
read off the photocathode in an odd and even field sequence, and that
is certainly true, what is generally not understood is that all of the
charge was read off the photocathode in each field.

Surely if what you say is true, there would have been no point in
camera manufacturers developing ACT circuitry, as the targets would
have had no residual charge at the end of each field?

Maybe I didn't make myself clear. There was still residual charge on
the cathode at the end of the field, of course, but the beam diameter
and charge diffusion was larger than the interlace shift.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

In article , Tony Quinn
writes
In message , Kennedy McEwen
writes

I don't think LCD panels are that smart.

They're incredibly stupid - even this one

http://www.sony.co.uk/biz/view/ShowP...d=35F166739819
E82B861D0175514CB62D?product=BVM-L230&pageType=Overview&category=BVM&site
=biz_en_GB

at more than 1o0k per unit - I don't imagine that sub 1k telly will be
any more intelligent

But at least that one "Faithfully reproduces interlaced signals,
emulating CRT monitors."

Now, if only they all did that, this thread would not exist! Where
would we be then? ;-)
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's ****ed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)

"Kennedy McEwen" wrote in message
...

So how does the TV discriminate between real motion in a small part of the
frame (couple of players on the pitch move between fields) and spatial
differences where the image of some objects in one field are spatially
different from the other field?

The logic would be along the lines of "if *any* so-called mice teeth are
detected between the two fields, treat the source as 50fps interlaced and
apply deinterlacing algorithms".


What if there is no motion in the image - does the TV get confused after a
while and decide it isn't interlaced after all? ;-)

No motion would likely be treated the same as a 2:2 pulldown - no problems
there.


How does it handle the difference between spatial differences in the
fields, motion differences and noise on old video recordings?

Please clarify what you mean by "spatial differences" in this context?
Motion differences = obvious mice teeth, so easy to detect.
Noise on old video recordings, at a guess, would have to be above a
pre-defined level before it managed to confuse the TV.


I don't think LCD panels are that smart.

It's less complicated than you think - it's just the same basic logic being
applied over and over again to one frame after another.

There are some other issues too though, which I haven't mentioned here yet -
for example, in the case of 50fps interlaced content, where the TV's 3-field
deinterlace mode is in operation (with each newly-created progressive frame
being made up of information from a combination of three adjacent fields),
the software has to be able to detect and respond to sudden camera changes -
otherwise you'd potentially end up with a new frame containing a mixture of
two different shots.