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Anonymous
Not applicable
3,644 Views
Message 1 of 9

Picture Quality - SD is poor - HD is excellent

I have had the latest BT Youview Box (Two blue lights on front) for about 2 weeks. Watching the SD channels through the Youview tuner the quality is not very good probably best described as poor definition. If I watch the same channels through the TV tuner the quality is good. The quality of the HD channels through the Youview box is however excellent.

 

My understanding is that standard definition on freeview is 576p but the youview box does not have this setting. You have to select 720P, 1080i or 1080p. Could it be the fact that the box is upscalling the channels to 720p or 1080i that is causing the problem and hence HD being Ok.

 

I am viewing everthing on the same TV (Panasonic) which is about 6 years old.

 

Any help appreciated.

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8 REPLIES 8
ubysam
Contributor
3,640 Views
Message 2 of 9

Re: Picture Quality - SD is poor - HD is excellent

Hi there,

 

Your theory might be a good one, What model of panasonic is it?

 

 

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Anonymous
Not applicable
3,635 Views
Message 3 of 9

Re: Picture Quality - SD is poor - HD is excellent

The Panasonic is a TX-32LXD700

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ab79
Aspiring Expert
3,593 Views
Message 4 of 9

Re: Picture Quality - SD is poor - HD is excellent

I've had the same problem with a few hd freeview boxes now and I tend to agree that the ups caking o
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ab79
Aspiring Expert
3,590 Views
Message 5 of 9

Re: Picture Quality - SD is poor - HD is excellent

.. continue with up scaling ( not up caking!!). I think detail ( including picture fuzz etc is being exposed due to the higher resolution).
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Anonymous
Not applicable
3,545 Views
Message 6 of 9

Re: Picture Quality - SD is poor - HD is excellent

Am I correct in saying that the native resolution for Freeview on SD channels is 576p?

 

If this is the case why are the manufacturers of the box not providing a setting for this resolution and instead having the box upscale causing poorer picture quality.

 

Is it perhaps that more modern TV's than I have cope much better with a signal from the box that has been upscaled and therefore my only solution is to get a new TV?

 

There seem to be quite a few people with the same problem - has anyone come up with a good solution?

 

BT Technical offered to send out an engineer "with special tools" but I cant't see what an engineer can do to improve the situation. It's the box causing the problem and I can't see them taking it apart and adjusting something manually inside. I therefore rejected the offer of an engineer at least for the time being.

 

I wonder if I have any right to cancel the BT TV contract with refund of installation £35 on the basis of poor picture quality on SD channels.

 

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ubysam
Contributor
3,535 Views
Message 7 of 9

Re: Picture Quality - SD is poor - HD is excellent

Sounds to me like your tv is doing a good/better job (subjective) of upscaling the built in tuner to 720p than the youview box,

 

your tv's screen reolution is 1366 x768 - in which case the best setting for the youview box to avoid unnecessary conversion will be 720p.

 

also worth noting that a lot of tv's although not usually panasonic will apply different picture settings (coulour/contrast/brightness etc) to different inputs so worth cheking this before you have a rant at BT

 

hth

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umpire
Distinguished Guru
3,528 Views
Message 8 of 9

Re: Picture Quality - SD is poor - HD is excellent

Even if you set the box to send 720 the TV will still have to do some additional scaling if it's using all 768 physical lines on the screen.

 

There is also the matter of overscanning that can mean even more scaling and lack of definition. 

See  http://www.engadget.com/2010/05/27/hd-101-overscan-and-why-all-tvs-do-it/

My Panasonic TV allows me to store two different on/off settings for overscanning, one for SD and one for HD. I just turn it off for both so I get as much detail as possible and the 1080 signal from my BT Vision+ box is mapped exactly to my screen's 1080 physical lines. 

 

If the BT Youview+ box allowed you to set the HDMI output to 576 then the HD channels would have to be downscaled and would look no better than SD. I assume that for this reason they only allow 720 or 1080 over HDMI.

Interestingly my BT Vision+ box does allow 576 over HDMI (even though it doesn't really make much sense). This is possibly because it doesn't have HD DVB-T2 tuners.

 

You can send 576 over SCART though this will then be an analogue signal so may be processed/displayed slightly differently by the TV. SCART doesn't support the higher 720 or 1080 formats so is no good for HD. 

 

 

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umpire
Distinguished Guru
3,517 Views
Message 9 of 9

Re: Picture Quality - SD is poor - HD is excellent

The HDTVtest web site benchmarks for the TX-32LXD700 state.

"Overscanning on HDMI, Component   2.5 percent"

I don't know if you can turn that off somewhere in the menus?

 

It doesn't state if the same overscan value applies to a signal coming from the built-in DTT Freeview tuner. You can normally spot if there's any difference if you view a news channel which has fixed graphics near the edge of the screen. 

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