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Freeview picture quality

(November 2008)

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IS
Inspector Sands
noggin posted:
Shouldn't be blockier in composite - if anything the composite subcarrier (and drop in chroma bandwith) should mask the blocking a bit. It will certainly be fuzzier though - even if you have a very good PAL decoder in your telly (and most don't)


Close up I can certainly see more 'blocks' and artifacts in composite than RGB, especially around DOGs and the like
NG
noggin Founding member
Inspector Sands posted:
noggin posted:
Shouldn't be blockier in composite - if anything the composite subcarrier (and drop in chroma bandwith) should mask the blocking a bit. It will certainly be fuzzier though - even if you have a very good PAL decoder in your telly (and most don't)


Close up I can certainly see more 'blocks' and artifacts in composite than RGB, especially around DOGs and the like


Ah - do you mean mosquito-noise (the HF noise around fine detail - like DOGs - caused by the loss of HF detail)? That will probably be made fizzier by subcarrier (which crawls as it has a multi-field sequence)

Blocking is slightly different and is caused by a near-total lack of HF detail, meaning there is only a DC component for each MPEG block, so the block structure becomes more apparent. This kind of artefact shouldn't be emphasised by PAL subcarrier, as it is an HF artefact introduced by a lack of HF source content, and should be softened slightly by composite carriage. (It is enhanced by fixed pixel displays - CRTs were softer and rounded off sharp HF detail - like block edges - a bit)
MI
Michael
The only channel I have problems with screen quality is Setanta 1. I have to soften my picture a lot to get rid of the blockiness.

Football on BBC, ITV and Five seems normal.
NG
noggin Founding member
Alexia posted:
The only channel I have problems with screen quality is Setanta 1. I have to soften my picture a lot to get rid of the blockiness.

Football on BBC, ITV and Five seems normal.


Hmm - football on both ITV1 DSat and ITV1 Freeview (in London) looks pretty awful to me. Five usually looks a lot better on DSat than Freeview (though it appears that the BBC is now providing Five with space on Astra 2D for them to appear on Freesat)

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