BBC HD vs ITV1 HD

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

Jamie, I gave up caring who was right and who was wrong in this thread a
long time ago because of your aggressive, unpleasant manner. It really is
tremendously off-putting. However, based on observation of your past
performance and your tendency to tell experienced professionals in u.t.b.
how to suck eggs, I suspect that it's you that's wrong on this one. For
what it's worth, though, I'd rather read Java Jive being reasonable and
wrong than you being repulsive but right.

One thing you haven't picked up on in your highly-defective "observations"
of me, is that any negative descriptions of me, or of my behaviour - made
either with, or without employing metaphors - will not be taken seriously.

If you don't provide evidence to back up your accusations (and there
absolutely isn't any evidence for them) then you really are just wasting
your time.

In addition, your calling me "repulsive" at the end was just plain rude, as
well as being hypocritical.

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

The blustering nature of your response has pretty much supplied all the
evidence I might need for my accusations.

You've made another negative description of my behaviour without evidence.
You're still stuck with using the same tactics, aren't you.


"[A]ny negative descriptions of me, or of my behaviour...will not be taken
seriously" - Well, as I don't take you at all seriously either, that's us
nice and even. Sometimes, however, people who make negative comments about
another person or their behaviour actually have a point.

If they had a point, they'd be able to provide evidence to back them up.


The key to happiness is working out when they're right and wrong, and
learning from it.

Evidence, or lack thereof, is very helpful in this process.


Sailing through life utterly convinced that whatever you do or say is 100%
right is the way of an arrogant arsehole.

Making a judgement based on evidence (there's that word again) is a far more
reasonable way.


I've already explained that I find your manner off-putting. That's
repulsion. If you choose to take it as a personal insult rather than a
comment on your posting style and its tendency to repel, I can't help
that.

If you choose to be repulsed by my posting style, then that's your problem
and not mine. I find your posting style extremely repulsive, and I'm
certainly not going to change anything based on a bunch of groundless,
sweeping and unfocussed allegations from a complete stranger.


You're right on one thing, though. By responding to trolls, I am wasting
my time.

Another insult - this time calling me a "troll". You're really clocking them
up, but your evidence score still remains at zero.

In article , Louis Barfe's
IbMePdErRoIoAmL writes
jamie powell wrote:
Are you thick or something?

For what it's worth, though, I'd rather read Java Jive being reasonable
and wrong than you being repulsive but right.

.... but he is wrong, anyway.

JJ's posting, and supporting web page is entirely reasonable. It makes
_far_ more sense (from a manufacturing perspective) to do it the
simplest way that delivers acceptable results.

I'm not sure I understand why de-interlace is desirable though, as an
interlaced digital signal can't be that bad to handle: a 50Hz refresh,
but with alternate A and B fields repeated would do it, as JJ suggests.
Finessing it would be the repeated field displayed at reduced brightness
(to approximate to phosphor decay).

So you'd decode and recover two streams of fields and buffer them. All
you have to do is read out to the display at 2x the buffer input, (with
a simple scaling of the RGB values for the second read of each field, if
you want to be clever, to approximate to phosphor decay). That's far
easier than a proper de-interlace, which would require interpolation to
be calculated for the 'older' field, for a 50Hz refresh (which is what
you'd want).

When people talk about the standardized film frame rate of 24fps, it of
course has a flicker rate of 48Hz (when projected). It's not really a
refresh rate, as the same frame is shown twice, but it's not a gimmick
either. It was found to be necessary to reduce apparent flicker.

So you don't really want a refresh rate of 25Hz, even if you could
validly produce one from a 25fps interlaced original video signal!

It's also the case that progressive scanning at slowish speeds gives
nasty temporal artefacts too, analogous to the effects of focal plane
camera shutters in photography: the top-left-to-bottom-right build up of
the picture is obvious on cuts particularly, and motion apparently
shimmers. You notice this particularly from the far end of John Lewis'
sales floor, or t'other end of the Richer Sounds showroom, when umpteen
plasma displays switch (almost) simultaneously. It looks a bit like a
high speed windscreen wiper sometimes.

It's a shame no manufacturer will talk about their techniques though.



--
SimonM
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"SpamTrapSeeSig" wrote in message
...

... but he is wrong, anyway.

And every single flat panel TV manufacturer is wrong too, then.


JJ's posting, and supporting web page is entirely reasonable. It makes
_far_ more sense (from a manufacturing perspective) to do it the simplest
way that delivers acceptable results.

I'm not sure I understand why de-interlace is desirable though, as an
interlaced digital signal can't be that bad to handle: a 50Hz refresh, but
with alternate A and B fields repeated would do it, as JJ suggests.
Finessing it would be the repeated field displayed at reduced brightness
(to approximate to phosphor decay).

So you'd decode and recover two streams of fields and buffer them. All you
have to do is read out to the display at 2x the buffer input, (with a
simple scaling of the RGB values for the second read of each field, if you
want to be clever, to approximate to phosphor decay). That's far easier
than a proper de-interlace, which would require interpolation to be
calculated for the 'older' field, for a 50Hz refresh (which is what you'd
want).

It wouldn't work. As Richard Tobin said, [quote] To do what a CRT does, it
would have to continuously fade the lines after it displayed them (even, to
a small extent, mixing them into the new lines for that field). That is
hardly "just buffering". In fact, it's a deinterlacing technique. [end
quote]

Even if you designed a TV which continously and gradually faded the lines to
simulate the behaviour of CRT phosphor lag (this would require many more
than 50 screen updates per second btw), the response time of current LCD
displays would be too slow to keep up.

Also bear in mind that, unlike CRTs, every pixel on an LCD screen updates
near-simultaneously.
On a CRT, a single electron beam "draws" the image, one line at a time, from
top to bottom. To accurately simulate this behaviour on an LCD is
non-trivial- it's a great deal more difficult than you seem to think, and it
would be vital if no conventional deinterlacing technique was going to be
employed.



When people talk about the standardized film frame rate of 24fps, it of
course has a flicker rate of 48Hz (when projected). It's not really a
refresh rate, as the same frame is shown twice, but it's not a gimmick
either. It was found to be necessary to reduce apparent flicker.

So you don't really want a refresh rate of 25Hz, even if you could validly
produce one from a 25fps interlaced original video signal!

It's also the case that progressive scanning at slowish speeds gives nasty
temporal artefacts too, analogous to the effects of focal plane camera
shutters in photography: the top-left-to-bottom-right build up of the
picture is obvious on cuts particularly, and motion apparently shimmers.
You notice this particularly from the far end of John Lewis' sales floor,
or t'other end of the Richer Sounds showroom, when umpteen plasma displays
switch (almost) simultaneously. It looks a bit like a high speed
windscreen wiper sometimes.

It's a shame no manufacturer will talk about their techniques though.

Yeah it'd stop you filling the information vacuum with stuff like the total
and utter bull**** like you've written above.

"Louis Barfe's IbMePdErRoIoAmL" wrote in
message ...
jamie powell wrote:

Another insult - this time calling me a "troll". You're really clocking
them up, but your evidence score still remains at zero.

You supply all the evidence anyone might need every time you touch the
keyboard. As for being a troll, you're trying to goad me into an argument
I have no interest in. I'll respond point by point to every minute detail
of what you say, you'll say that I haven't supplied any evidence when I
clearly have, I'll reiterate the points with more examples, and so on.
Nothing will have been gained. I will have just wasted an awful lot of
valuable time having a pointless argument with someone who might not even
exist. That's trolling, and it won't work with me.

I've read this in its entirety, and you just sound pathetic to be honest
mate.
I can't even be bothered responding directly to any of it.

In message , jamie powell
writes:
[]
Film sources are 25fps, which means that no deinterlacing is necessary - the
TV will detect a lack of movement between the pairs of interlaced fields and
switch to a simple "pulldown" mode.


I'm assuming that the incoming signal is at the full vertical
resolution, one odd field then one even one, per film frame. If not,
don't read on.

I'm curious: _how_ will the TV detect "a lack of movement" between the
pairs of interlaced fields - _if_ they are truly scans of the odd and
even "lines" of the original film frame?
--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)[email protected]+Sh0!:`)DNAf
** http://www.soft255.demon.co.uk/G6JPG-PC/JPGminPC.htm for ludicrously
outdated thoughts on PCs. **

I hate people who quote Shakespeare at you but are proud that they can't add
up.
Stupid People. - Carol Vorderman (Radio Times, 1-7 March 2003)

In message , Java Jive
writes:
It seems pretty clear to me that my description of buffering doesn't
mention anywhere line doubling which is an essential part of your
description of bob-deinterlacing.

With buffering, the signal is collected in memory until a complete
unit (see below) is received, and then switched through to the display
as a unit, whereas with the 'classic' CRT, the signal is simply sent
straight through to the CRT as it is received in real time.

By a 'unit', I mean a single field of even or odd lines for interlaced
sources such as a broadcast stream, or a frame for a progressive
source such as a DVD.
[]
When you say "switched through to the display as a unit", in what sort
of timeframe are you saying this display updating happens - a fraction
of a line, or what? (Not grinding any axe he just seeking
clarification.)
--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)[email protected]+Sh0!:`)DNAf
** http://www.soft255.demon.co.uk/G6JPG-PC/JPGminPC.htm for ludicrously
outdated thoughts on PCs. **

I hate people who quote Shakespeare at you but are proud that they can't add up.
Stupid People. - Carol Vorderman (Radio Times, 1-7 March 2003)

In message , Java Jive
writes:
I think we're talking at cross purposes here. Rereading your post, I

We sure are.

For we numptys trying to follow this discussion, I think we need to know
how LC (and plasma) displays are updated - is it:

1. each individual pixel is updated at approximately the rate that it is
received, thus simulating a CRT (except without phosphor fade),

or

2. The whole screen of pixels is refreshed in some incredibly short
time, once a field or frame?
[]
--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)[email protected]+Sh0!:`)DNAf
** http://www.soft255.demon.co.uk/G6JPG-PC/JPGminPC.htm for ludicrously
outdated thoughts on PCs. **

I hate people who quote Shakespeare at you but are proud that they can't add up.
Stupid People. - Carol Vorderman (Radio Times, 1-7 March 2003)

In message
. co.uk.invalid, Alan
Pemberton writes
Mike Henry wrote:

No. With interlaced 50fps video it's not half of "the" image. It's a
half-resolution image, followed by a DIFFERENT half-resolution image where
there camera captured a different 50th of a second of time.

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.

As you admit. It's 50 fields per second. We get lovely smooth motion
thanks to capturing 50 different pictures per second and transmitting them
in half the bandwidth.

Trading vertical resolution against temporal resolution does seem to
work, yes. And to be honest there's no other satisfactory way to shoot
fast motion like sport at 25fps (50i as opposed to 25p). Subjectively
though, 25p (even when shuttered to 1/50 sec to reduce motion blur)
looks really unconvincing when contrasted with 50i.

Indeed. There's not really any other way to do that. 50 non-interlaced
frames per second would look quite different.

50p does look somewhat different, yes.
--
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 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?

If it's not done that way, it breaks the rule of the easiest solution
being adopted for manufacture, and there has to be some complex reason
why.
--
SimonM
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