Five worse quality than it was?

"Chris K" wrote in message
o.uk...

"Peter Duncanson" wrote in message
...
On Thu, 1 Oct 2009 15:57:59 +0000 (UTC), "Dave Saville"
wrote:

On Thu, 1 Oct 2009 15:05:28 UTC, "Bill Wright"
wrote:


"Mark Carver" wrote in message
...
Zimmy wrote:
Is it just me or does channel five look more compressed than it did
before the retune?

Yes, and unconfirmed reports that it is running at 544x576 (which is in
breach of their Ofcom licence)
It's 704 x 576 here in Micklebring.


Er, how do you tell?

In my case, by recording on a Humax PVR9200T, transferring it to a PC
and looking at the details with VideoReDo.

I recorded a few minutes of "Murder in Greenwich" this afternoon. (From
the Divis transmitter.) It was 544x576.

Judging by the picture quality on the screen just now two hours later
I'd guess that it is still at that resolution.

--
Peter Duncanson
(in uk.tech.digital-tv)

544x576 2MBit (Ridge Hill) at the moment 17:40 1/10/09


Currently 544x576 from Winter Hill also.

"Dave Saville" wrote in message
...
On Thu, 1 Oct 2009 15:05:28 UTC, "Bill Wright"
wrote:


"Mark Carver" wrote in message
...
Zimmy wrote:
Is it just me or does channel five look more compressed than it did
before the retune?

Yes, and unconfirmed reports that it is running at 544x576 (which is in
breach of their Ofcom licence)
It's 704 x 576 here in Micklebring.


Er, how do you tell?

The info comes up for every channel on my analyser. I think all the others
in that mux were 544x576.

Bill

Its more than likely a cock up, judging from the 'technical prowess' of most
of the folk now in charge of quality these days.

Brian

--
Brian Gaff -
Note:- In order to reduce spam, any email without 'Brian Gaff'
in the display name may be lost.
Blind user, so no pictures please!
"Mark Carver" wrote in message
...
Zimmy wrote:
Is it just me or does channel five look more compressed than it did
before the retune?

Yes, and unconfirmed reports that it is running at 544x576 (which is in
breach of their Ofcom licence)

Page 3:-

http://www.ofcom.org.uk/tv/ifi/tech/...e/dttt_uk2.pdf

"Mark Carver" wrote in message
...
Roger R wrote:
"Mark Carver" wrote in message
...
Zimmy wrote:
Is it just me or does channel five look more compressed than it did
before the retune?
Yes, and unconfirmed reports that it is running at 544x576 (which is in
breach of their Ofcom licence)

Page 3:-

http://www.ofcom.org.uk/tv/ifi/tech/...e/dttt_uk2.pdf


I have compiled the following table of the channels available to me on a
SilverCrest Comag DVB-T SL65 receiver from the Rowridge transmitter
signals.

Channel order as given by receiver.

[snip]

Some surprises in there.
If the Ofcom spec is still valid then quite a few are out of order.

No, in fact only one station is breaking Ofcom's rules, and that's C5.

The Ofcom 'Qualifying Services' that have to be at a minimum resolution on
DTT of 704x576 are only ITV1, C4, and Five. The rest can (and do) use
whatever they want. I'm not sure whether the Beeb have to conform, but all
four of their main services are at 720x576 anyway


Thanks for the clarification.

Over on Digital Spy someone calling themselves Ray Cathode in this thread:
http://www.digitalspy.co.uk/forums/s....php?t=1136391
he says, (to paraphrase and perhaps to misinterpret it)
In the senario where the bit rate is constrained, the lower pixel resolution
picture may be superior to the higher pixel resolution picture. Its all in
the quality of the algorithms of the encoder. Presumably the higher pixel
picture requires more compression to be accomodated within the contrained
bit rate.

I'm not sure how that squares with the op's comment that Five now looks
worse with the lower pixel resolution.

Roger R

Roger R wrote:

Thanks for the clarification.

Over on Digital Spy someone calling themselves Ray Cathode in this thread:
http://www.digitalspy.co.uk/forums/s....php?t=1136391
he says, (to paraphrase and perhaps to misinterpret it)
In the senario where the bit rate is constrained, the lower pixel resolution
picture may be superior to the higher pixel resolution picture. Its all in
the quality of the algorithms of the encoder. Presumably the higher pixel
picture requires more compression to be accomodated within the contrained
bit rate.

I'm not sure how that squares with the op's comment that Five now looks
worse with the lower pixel resolution.

Yes, you raise a good point. This delves us into the murky world of MPEG
compression algorithms, and all sorts of variables to consider.

"jamie powell" wrote in message
...

"Chris K" wrote in message
o.uk...

"Peter Duncanson" wrote in message
...
On Thu, 1 Oct 2009 15:57:59 +0000 (UTC), "Dave Saville"
wrote:

On Thu, 1 Oct 2009 15:05:28 UTC, "Bill Wright"
wrote:


"Mark Carver" wrote in message
...
Zimmy wrote:
Is it just me or does channel five look more compressed than it did
before the retune?

Yes, and unconfirmed reports that it is running at 544x576 (which is
in
breach of their Ofcom licence)
It's 704 x 576 here in Micklebring.


Er, how do you tell?

In my case, by recording on a Humax PVR9200T, transferring it to a PC
and looking at the details with VideoReDo.

I recorded a few minutes of "Murder in Greenwich" this afternoon. (From
the Divis transmitter.) It was 544x576.

Judging by the picture quality on the screen just now two hours later
I'd guess that it is still at that resolution.

--
Peter Duncanson
(in uk.tech.digital-tv)

544x576 2MBit (Ridge Hill) at the moment 17:40 1/10/09


Currently 544x576 from Winter Hill also.


I get it from Black Hill so probably the lower res there too.
Looks awful on my 36" CRT. Why are they bringing in HD when they can't even
get it together on SD?

Z

Mike Henry wrote:

Yes, you raise a good point. This delves us into the murky world of MPEG
compression algorithms, and all sorts of variables to consider.

Indeed, it is a good point, but nevertheless - Five are still in a very
clear breach of their licence aren't they?

Yes, they are, though reports in Digital Spy (from reliable types) suggest
that on Crystal Palace they are running at 704. How wonderfully London centric
if true !


--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

Mark Carver wrote:
Mike Henry wrote:

Yes, you raise a good point. This delves us into the murky world of
MPEG compression algorithms, and all sorts of variables to consider.

Indeed, it is a good point, but nevertheless - Five are still in a very
clear breach of their licence aren't they?

Yes, they are, though reports in Digital Spy (from reliable types)
suggest that on Crystal Palace they are running at 704. How wonderfully
London centric if true !

From a less than reliable source:-

http://www.ukfree.tv/fullstory.php?storyid=1107051625

It would seem the lo-res C5 is only temporary, and it will be restored to
704x576 in a couple of weeks.

I wonder if it's a distribution problem, because the Mux 2 coders are in
different parts of the country, to the SDN/Mux A ones ?

Of course what's so stupid about Ofcom's minimum resolution directive, it that
there are no equivalent rules about minimum bit rates ! Perhaps the poor
dears in Ofcom Towers have got JPEG and MPEG mixed up ?

--
Mark
Please replace invalid and invalid with gmx and net to reply.

www.paras.org.uk

"Mark Carver" wrote in message
...
Mark Carver wrote:
Mike Henry wrote:

Yes, you raise a good point. This delves us into the murky world of
MPEG compression algorithms, and all sorts of variables to consider.

Indeed, it is a good point, but nevertheless - Five are still in a very
clear breach of their licence aren't they?

Yes, they are, though reports in Digital Spy (from reliable types)
suggest that on Crystal Palace they are running at 704. How wonderfully
London centric if true !

From a less than reliable source:-

http://www.ukfree.tv/fullstory.php?storyid=1107051625

It would seem the lo-res C5 is only temporary, and it will be restored to
704x576 in a couple of weeks.

I wonder if it's a distribution problem, because the Mux 2 coders are in
different parts of the country, to the SDN/Mux A ones ?

Of course what's so stupid about Ofcom's minimum resolution directive, it
that there are no equivalent rules about minimum bit rates ! Perhaps the
poor dears in Ofcom Towers have got JPEG and MPEG mixed up ?

How come my analyser declared that C5 was 704x 576 from Emley on the day
when this discussion started?

Bill

On Sat, 03 Oct 2009 14:20:29 +0100, Mark Carver wrote:


I wonder if it's a distribution problem, because the Mux 2 coders are in
different parts of the country, to the SDN/Mux A ones ?

`five' is distributed to the transmitters via the feed on Eutelsat W2 at 16
East on transponder D9 11,682 GHz Vertical, is it not?

http://www.lyngsat.com/ew2.html

Does anybody know the resolution of those transmissions?

And why is the resolution normal at Emley Moor and not at Winter Hill,
Belmont, etc?

What is different about the facilities at Emley Moor?