HD post-switchover

Andrew wrote:
On Thu, 04 Oct 2007 22:56:49 +0100, Mike Henry
wrote:

So the extra 560 pixels in the X axis counts for nothing?

Only if it's used.

Either it is 720p or it isn't.


1080i was supposed to be 1920x1080, but they're actually using 1440x1080.


In this wonderful SD age of broadcasting we currently
have many channels, including major national ones not just cheap
shopping channels (E4/More4/C4+1/ITV2,3,4/Five US/Five Life)
broadcasting at VHS resolutions. Given that track record they'll all
do the same with HD, as well as winding down the bitrate until it's
just at the point when people stop complaining.

Which has nothing to do with what I was referring to. When limited
bandwidth is taken into account 720p makes a lot more sense than
1080p.


No-one suggested using 1080p.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

Stephen wrote:
"DAB sounds worse than FM" [email protected] wrote in message
...
DAB sounds worse than FM wrote:
There's an interesting Ofcom document about it he

http://www.ofcom.org.uk/radiocomms/d.../hdmasters.pdf


Pages 15-16 say about 40 Mbps of extra capacity can be used to allow
5 HD channels using 720p on a dedicated DVB-T2 mux, and to allow
this the bit rates of existing SD channels would have to be squeezed
to the tune of 8.7 Mbps in total.

Hmmmmm. So they want to use 720p, which is medium-definition, IMO,
not high-definition, and they need to squeeze the bit rates
significantly, which are already squeezed too much as it is.

It's a good job I'm planning to get satellite before 2012!! And I
sympathise with everybody not getting it! And they'd better not use
720p on satellite!!!!

Squeezing HD into the existing muxes is ridiculous, but it may be
politically necessary for Ofcom to suggest this, in the interests of
the spectrum auction. Ultimately, keeping BBC HD and ITV HD off
terrestrial will prove politically impossible, and Ofcom will change
their tune.


But Ofcom is suggesting that 5 HD channels could launch.


720p is favoured by the EU,


Screw the EBU!


but has no chance in competition with
1080i, because 1080 is a bigger number.


*And* a significantly higher resolution.


Even if the 720 picture was
of higher quality, 1080 will always sell better because it sounds
like a bigger, better, higher definition system.


Absolutely - it is higher definition.


The TV broadcasters
prefer 1080i, and will use it assuming they get all or most of
channels 31 to 40 and 63 to 68 for HD, which is what I would hope and
expect.


They won't be given any of it though. How much they end up winning at an
auction is debatable, but I think there'll be a pretty high demand for it.


Conversely, if I owned a mobile phone company I wouldn't want to gear
up production for a non-standard UK-only spectrum allocation which
the biggest, richest and longest established state and commercial
broadcasters wanted for themselves. The main broadcasters would be
waiting for my company to go under, and it would be in their
interests to do as little as possible to prevent it.


I don't think there's any agreed upon spectrum for wireless broadband
though, is there?

Also, DVB-H is meant to use Bands IV/V, so there's no problem with that
using it.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

On Fri, 05 Oct 2007 00:15:26 GMT, "DAB sounds worse than FM"
[email protected] wrote:

80% higher resolution or 35% higher, they're both a lot higher than 720p.

And even lowly (by your incomprehensible standards) 720p is a damn
sight better than SD 720x576, whish I notice you left out of your
lecture.
--
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In article , DAB sounds worse
than FM wrote:
The actual vertical resolution of 720p is very similar to 1080i, both
of these are vastly superior to 576i.

1920 x 1080 x 0.8 = 1,658,880 pixels *(1080i)

1280 x 720 = 921,600 pixels *(720p)

1,658,880 / 921,600 = 1.8

I thought it was customary to express the resolving power of imaging
systems in the form of linear resolution, e.g. dpi, lines/mm and so on,
because this corresponds roughly to how detailed the images look to the
eye. Using the "area resolution" or total number of pixels could be said
to give figures that are misleadingly high.

Rod.

Andrew wrote:
On Fri, 05 Oct 2007 00:15:26 GMT, "DAB sounds worse than FM"
[email protected] wrote:

80% higher resolution or 35% higher, they're both a lot higher than
720p.

And even lowly (by your incomprehensible standards)


I thought my standards would be very easy to understand, to be honest - they
should use the higher resolution HDformat and not the lower resolution
format.


720p is a damn
sight better than SD 720x576, whish I notice you left out of your
lecture.


720p does offer a significantly higher resolution than SD. But that doesn't
alter the fact that 720p (1280x720) *is* medium-definition compared to 1080i
(1920x1080).


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

Roderick Stewart wrote:
In article , DAB sounds worse
than FM wrote:
The actual vertical resolution of 720p is very similar to 1080i,
both of these are vastly superior to 576i.

1920 x 1080 x 0.8 = 1,658,880 pixels (1080i)

1280 x 720 = 921,600 pixels (720p)

1,658,880 / 921,600 = 1.8

I thought it was customary to express the resolving power of imaging
systems in the form of linear resolution, e.g. dpi, lines/mm and so
on, because this corresponds roughly to how detailed the images look
to the eye. Using the "area resolution" or total number of pixels
could be said to give figures that are misleadingly high.


Figures such as dpi are specific to each different model of TV, so you can't
use that figure to refer to an HDTV format. Therefore area resolution has to
be used instead.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

On Fri, 05 Oct 2007 07:19:45 GMT, "DAB sounds worse than FM"
[email protected] wrote:

720p does offer a significantly higher resolution than SD. But that doesn't
alter the fact that 720p (1280x720) *is* medium-definition compared to 1080i
(1920x1080).

Yes, but given the bandwidth constraints, would you prefer a good
quality 720p or an average quality 1080i/p. Actually don't answer
that, I know you can't wait to launch into being "Freeview HD looks
worse than SD" and whinge about it endlessly.
--
Andrew, contact via http://interpleb.googlepages.com
Help make Usenet a better place: English is read downwards,
please don't top post. Trim replies to quote only relevant text.
Check groups.google.com before asking an obvious question.

In article , DAB sounds worse than FM
wrote:
I thought it was customary to express the resolving power of imaging
systems in the form of linear resolution, e.g. dpi, lines/mm and so
on, because this corresponds roughly to how detailed the images look
to the eye. Using the "area resolution" or total number of pixels
could be said to give figures that are misleadingly high.

Figures such as dpi are specific to each different model of TV, so you can't*
use that figure to refer to an HDTV format. Therefore area resolution has to*
be used instead.

I don't see why it *has* to be used. "Area resolution" gives the total amount
of information per frame, and is a useful indication of the bandwidth or
storage capacity needed to handle the signal, but "linear resolution" is better
related to how the picture will look.

An electronic image has no physical size, so of course you don't use units like
dpi that refer to physical dimensions. You have to use the height or width of
the picture itself as a reference and give pixels/width, or pixels/height.

Not surprisingly, advertisers like to quote the performance of electronic
cameras in "megapixels", a term I don't recall ever seeing until the advent of
electronic still photography, but all the figures I've ever seen for the
optical resolution of imaging devices and the subjective performance of
television systems have been expressed as linear resolution.

Rod.

Andrew wrote:
On Fri, 05 Oct 2007 07:19:45 GMT, "DAB sounds worse than FM"
[email protected] wrote:

720p does offer a significantly higher resolution than SD. But that
doesn't alter the fact that 720p (1280x720) *is* medium-definition
compared to 1080i (1920x1080).

Yes, but given the bandwidth constraints, would you prefer a good
quality 720p or an average quality 1080i/p.


1080p on Freeview? Which planet are you on?

And which would I prefer on Freeview out of 720p or 1080i? I'd prefer 1080i
*and* sufficient bit rate levels.


Actually don't answer
that, I know you can't wait to launch into being "Freeview HD looks
worse than SD" and whinge about it endlessly.


What a pathetic, pathetic suggestion. That's not worthy of a response.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info

Roderick Stewart wrote:
In article , DAB sounds worse
than FM wrote:
I thought it was customary to express the resolving power of imaging
systems in the form of linear resolution, e.g. dpi, lines/mm and so
on, because this corresponds roughly to how detailed the images look
to the eye. Using the "area resolution" or total number of pixels
could be said to give figures that are misleadingly high.

Figures such as dpi are specific to each different model of TV, so
you can't use that figure to refer to an HDTV format. Therefore area
resolution has to be used instead.

I don't see why it *has* to be used.


Because you need to refer to some parameter, and dpi is dependent on the TV
set, so you can't refer to that, because everybody's TV will be different.


"Area resolution" gives the
total amount of information per frame, and is a useful indication of
the bandwidth or storage capacity needed to handle the signal, but
"linear resolution" is better related to how the picture will look.


Area resolution refers to the picture "sharpness" according to a book I've
got on digital TV and HD by Charles Poynton.


An electronic image has no physical size, so of course you don't use
units like dpi that refer to physical dimensions. You have to use the
height or width of the picture itself as a reference and give
pixels/width, or pixels/height.

Not surprisingly, advertisers like to quote the performance of
electronic cameras in "megapixels", a term I don't recall ever seeing
until the advent of electronic still photography, but all the figures
I've ever seen for the optical resolution of imaging devices and the
subjective performance of television systems have been expressed as
linear resolution.


I think it's very useful to categorise digital cameras in terms of the
number of megapixels.


--
Steve - www.digitalradiotech.co.uk - Digital Radio News & Info