Is the MPEG-2 quality higher on Freeview ?
amstereofan
pixalation is very noticable. Is it better on Freeview (no signal here)
John J Good
"amstereofan" <listen_to...@www.amstereoradio.tk> wrote in message
news:3f31...@news.greennet.net...
> ITV1 on Sky is terrible. Any action scenes like with The Bill and the
> pixalation is very noticable. Is it better on Freeview (no signal here)
>
>
JJG
Stephen Neal
Yep - ITV1 is compressed to a lower data rate on DSat than DTT/Freeview. As
a result MPEG artefacting is more visible on the DSat feeds IMHO.
Steve
amstereofan
"Walt Davidson" <wal...@tiscali.co.uk> wrote in message
news:vc43jvk8973rjkula...@4ax.com...
> talk about on Sky. I think your equipment must be defective.
>
No any box will show it not just a $ky one. It just shows how good analogue
is or was we'll be saying in a few years :-(
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amstereofan
"Stephen Neal" <stephe...@NOSPAM.as-directed.com> wrote in message
news:bgs5jh$cue$1$8300...@news.demon.co.uk...
So is it near 100% compared with analogue terrestrial ?
Charles Ellson
<bgs5jh$cue$1$8300...@news.demon.co.uk>
stephe...@NOSPAM.as-directed.com "Stephen Neal" wrote:
Try tuning to Grampian instead of ITV1 (which one?), there doesn't seem
to be any pixellation there.
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John J Good
> On Thu, 7 Aug 2003 04:43:26 +0000 (UTC), cha...@ellson.demon.co.uk
> (Charles Ellson) wrote:
>
> >Try tuning to Grampian instead of ITV1 (which one?), there doesn't seem
> >to be any pixellation there.
>
> curious disparity between some people's experiences and mine. Perhaps
> it's a function of which ITV Region you happen to watch. Mine is ITV1
> Central, and I get no noticeable pixelation on the picture via Sky.
>
> Also, AIUI, some of the smaller terrestrial analogue relay stations
> take their feed from the Astra satellite transmission, so if there was
> anything wrong with it, the problem would be replicated on the
> analogue relay.
>
> --
> Walt Davidson Email: g3nyy @freeuk.com
It would be interesting to know if all the ITV regions use the same
compression levels on Sky, or if they vary from region to region. I suspect
everyone experiences a little pixelization (even if you don't notice it
much), as this is a in-built result of MPEG video when its compressed to the
levels used by many current broadcasters. I must say that on average, I
find the pictures are excellent most of the time. The one exeption is when
football is shown. The grass of a football pitch seems to be very demanding
on the current levels of compression used by ITV, and this does result in
noticeable pixelization when football is screened. Sky Sports however, show
a lot of football, but use higher bitrates and the football pictures are
excellent all the time.
If anyone knows the bitrates used by all the regions of ITV1, please post.
One thing is for certain, and that is that ITV1 and ITV2 are better quality
on freeview than they are on the Sky platform.
Regards JJG
BillR
> "Walt Davidson" <wal...@tiscali.co.uk> wrote in message
> news:vc43jvk8973rjkula...@4ax.com...
>> On Wed, 6 Aug 2003 20:22:53 +0100, "amstereofan"
>> <listen_to...@www.amstereoradio.tk> wrote:
>>
>>> ITV1 on Sky is terrible. Any action scenes like with The Bill and
>>> the pixalation is very noticable. Is it better on Freeview (no
>>> signal here)
>>
>> In all seriousness, I don't get any of this "pixelation" that people
>> talk about on Sky. I think your equipment must be defective.
>>
>
> No any box will show it not just a $ky one. It just shows how good
> analogue is or was we'll be saying in a few years :-(
transmissions.
The jagglies on sloping lines on digital are particularly annoying.
Watch any good quality live transmission and compare the digital & analogue
versions on a 32" good quality TV.
The analogue is far better.
Chris Vowles
<deepthought@NO_spammers-here.cyberdude.com> wrote:
>The analogue is far better.
Yes a good Analogue PAL picture will always be better than MPEG2
Digital Compressed picture because the nature of compression is to
lose some information to save space, although of course the higher the
bit rate the better MPEG2 becomes.
Like you I find the digital artifacts around lines and subtitles/logos
particularly distracting.
I have tried to simulate the effects of MPEG2 compression here
http://www.vowles-home.demon.co.uk/Sat/Digital-effects.htm
Chris
u1061771156
Steve,
Do you have figures comparing them?
Mike.
u1061771156
>> >ITV1 on Sky is terrible. Any action scenes like with The Bill and the
>> >pixalation is very noticable. Is it better on Freeview (no signal here)
>>
>> In all seriousness, I don't get any of this "pixelation" that people
>> talk about on Sky. I think your equipment must be defective.
>
>No any box will show it not just a $ky one. It just shows how good analogue
>is or was we'll be saying in a few years :-(
I have wondered whether newer boxes might be better. Whilst MPEG2 defines
the nominal decoding algorithm, one could imagine it being 'tweaked' to
identify cases where bandwidth is limited and produce a less obvious
degredation (e.g. blurring the edges of the DCT blocks when the higher
frequency components have all been dropped and they mismatch with the
adjacent blocks.)
Has anyone heard of anything like this being implemented?
Mike.
Stephen Neal
"u1061771156" <u1061...@csi.com> wrote:
ITV1, ITV2 and ITV News Channel have just under half of a 64QAM mux - which
means they have approx 12Mbs for the three channels. This implies an
average of approx 4Mbs - though ITV2/ITVNC may be statmuxed together with
ITV1 separately coded at a fixed rate?
AIUI ITV1 on Dsat is statmuxed but given that most ITV1s are showing pretty
much the same content most of the time (delays are added to improve on
this?) this may not be brilliantly effective - and the average rate I have
seen reported sits at about 3Mbs.
Steve
Andrew528520
>pixalation is very noticable. Is it better on Freeview (no signal here)
>
LOL funny you should say that freeview seems to be far superior to sky when it
comes to picture quality. pictures are much much clearer and sharper even
useing a plasma tv screen the differance is noticable. I wonder if this has
anything to do with sky useing technology that is over ten years old. If BBC
starts broadcasting paychannels i think sky will have to rethink either there
charges or upgrade the technology they use to match the quality of freeview.
Dale Richards
> Sky Sports however, show a
> lot of football, but use higher bitrates and the football pictures
> are excellent all the time.
I find that the overall picture quality is *far* better on the Sky Sports
and Sky Movies channels than on any other channels. My guess is that they
use much higher bitrates. I don't know any of the figures but as far as I
can tell, the effective quality on the Sky Movies channels is comparable
with DVD.
Charles Ellson
<l9v3jvke5i076spj0...@4ax.com>
wal...@tiscali.co.uk "Walt Davidson" wrote:
> On Thu, 7 Aug 2003 04:43:26 +0000 (UTC), cha...@ellson.demon.co.uk
> (Charles Ellson) wrote:
>
> >Try tuning to Grampian instead of ITV1 (which one?), there doesn't seem
> >to be any pixellation there.
>
> Actually, Charles, you may have hit on the explanation for this
> curious disparity between some people's experiences and mine. Perhaps
> it's a function of which ITV Region you happen to watch. Mine is ITV1
> Central, and I get no noticeable pixelation on the picture via Sky.
>
> Also, AIUI, some of the smaller terrestrial analogue relay stations
> take their feed from the Astra satellite transmission, so if there was
> anything wrong with it, the problem would be replicated on the
> analogue relay.
>
Something else that comes to mind is that Grampian's transponder has
the least number of channels on it (Grampian, STV, Channel, ITV2, UTV
and a couple of "others"). Is the compression method constant or does it
adjust "on the fly" if too many Mbits come along? With fewer channels, I
assume that there is relatively more reduntancy possible.
Ant
>If some sort of PID branching could be arranged, during networked
>programmes there could be a single high bitrate stream, with local
>material branching off and being statmuxed.
>Of course, this is just theory, and each time I've mentioned it
>previously I've been shot down.
It is certainly possible in theory (I believe the DVB system allows
for this kind of chicanery, although whether the Sky boxes support it
is another matter) but apparently the opts in and out need to be
signalled far in advance of when they are needed, and the end result
is far from smooth.
With ITV having ad breaks every 15 minutes or so it would just be too
much doodoo for a dollar.
Chris p
keep the money rather than using a higher bitrate :-(