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Strange phenomenon on Panasonic 32LXD700
Lizzybif
13-12-2007
I have had this TV for a couple of weeks and I love it!

However, I have noticed something quite strange a few times and this is people's faces 'morphing' when they nod or shake their head! It's as if part of their face stays put whilst the rest moves!No it isn't Joan Rivers or other cosmetically enhanced persons!

It doesn't happen all the time so I am hoping it is something to do with the broadcast rather than a problem with the TV?

Has anyone else noticed this?
fboy
14-12-2007
Glad you like the TV, no never experienced this at all.
Lizzybif
14-12-2007
Originally Posted by fboy:
“Glad you like the TV, no never experienced this at all.”

Does it sound like a problem with the TV or a problem with the programme do you think?
I would have thought if it was the TV it would happen all the time?
chrisjr
14-12-2007
Originally Posted by Lizzybif:
“I have had this TV for a couple of weeks and I love it!

However, I have noticed something quite strange a few times and this is people's faces 'morphing' when they nod or shake their head! It's as if part of their face stays put whilst the rest moves!No it isn't Joan Rivers or other cosmetically enhanced persons!

It doesn't happen all the time so I am hoping it is something to do with the broadcast rather than a problem with the TV?

Has anyone else noticed this?”

Bet you are watching a digital channel when it does this. And most likely not BBC1 or BBC2 either.

I've noticed this effect on several freeview channels, useually the ones that use the highest compression rates (ITV4 for instance). Would lay odds it is an artifact of the MPEG compression system used for digital TV.

The harder the broadcasters drive the encoders to squeeze ever more channels out of the limited resources of DTT the more likely these things will be.

If you talk geek there is an explanation of how MPEG encoding works by the BBC.

http://www.bbc.co.uk/rd/pubs/papers/...paper_14.shtml

What is likey to be the cause here is the way the MPEG encoder at the broadcast end and the decoder in your TV handle motion. There is within MPEG a predictive element, wher the decoder effectively "guesses" what the next picture frame will be based on the preceeding frames. If it gets this wrong then you can get the kind of weird effects you have noticed.

The other thing that is interesting in that BBC paper is that it states an acceptable picture can be obtained from MPEG-2 encoding at 6MB/s. Based on the capacity of a DTT multiplex and the number of channels actually being broadcast I'd say that rate would get rid of about two thirds of the channels on freeview if it were ever used!
Lizzybif
14-12-2007
Thanks Chris! Afraid I don't talk geek!

Yes it is on digital I see it and you are quite correct in that it is on the 'poorer' channels mostly although it was on ITV1 last night which is usually pretty good.
Mind you I think programmes themselves seem to differ in quality?
So effectively, it is not a problem with the Tv then but the broadcasts?

What TV do you have?
chrisjr
14-12-2007
The TV I have is a LG but that is irrelevant because it is analogue. I only use it as a display for the TVonics PVR .

The artifacts you get from digital TV are a combination of the encoder used at the transmission end and the decoder at your end. So you cannot entirely rule out the TV. But the broadcasters using really low bitrates for their channels doesn't help at all.

The BBC do at least make some effort. ITV1 is probably the best of their channels, ITV4 probably the worst! Especially noticable if a programme starts out on ITV1 and transfers to ITV4, the drop in picture quality is very obvious!
Lizzybif
14-12-2007
Thanks again Chris.

I'm not sure what to do as I can't see Panasonic changing my TV on the strength of this?

It is so annoying to spend a lot of money on a TV to get this kind of 'fault'.
Wonder whether broadcasts will improve once analogue is switched off?
chrisjr
14-12-2007
It isn't really a TV fault as such. it is simply making the best of the signal it is being fed with. I don't think i have seen any STB or TV that doesn't exhibit these artifacts.

It is a fact of life given the low bitrates the broadcasters have chosen to use. And I seriously doubt analogue switch off will make one jot of difference. The capacity of DTT won't dramatically alter over what it is now, especially on the ITV mux for example. So you will still have the same number of channels squeezed into the same space as now.

The only real solution would be for someone to compel ITV to close ITV4 (and maybe 3 as well) so the remaining ITV channels can have a decent share of the available capacity on the ITV mux. Probably have more chance of winning the lottery by NOT buying a ticket than that happening Or give ITV another mux to play with and tell them to move ITV3/4 over to that and up the bitrate on what's left. Again i feel a lottery win coming on.
Lizzybif
14-12-2007
If only Freeview would get rid of a lot of the rubbish channels!

Is this kind of problem on Sky as well?

Hope the lottery win you feel coming on is me!!!!!
chrisjr
14-12-2007
If channels on Sky use the same silly bitrates as on Freeview then yes. They both use MPEG commpression systems. For instance if ITV fed Freeview and Sky the exact same encoder output on ITV4 then the Sky version would look just as horrid as the Freeview version.

Difference is that satellite has way more capacity than DTT so you can fit many more channels in at sensible bitrates.
Lizzybif
14-12-2007
Think I will just stick with Sky as the main programmes I watch are really good on this TV so no sense shelling out about £20 per month to Sky when I might get problems with it as well.

Just a shame that broadcasters can get away with this!

Ah well nothing is perfect. Not even me!

Thanks a lot for the advice Chris!
DK71
15-12-2007
Could someone who has this telly confirm it does
picture in picture and the picture in picture can be
resized & moved from corner to corner?

I was thinking of buying myself this telly for xmas.

http://www.digitalspy.co.uk/forums/s...d.php?t=705313
Lizzybif
15-12-2007
Originally Posted by Lizzybif:
“Think I will just stick with Sky as the main programmes I watch are really good on this TV so no sense shelling out about £20 per month to Sky when I might get problems with it as well.

Just a shame that broadcasters can get away with this!

Ah well nothing is perfect. Not even me!

Thanks a lot for the advice Chris!”


Oops! Meant stick with Freeview.
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