TV Picture Quality

[searchlight]

I have a 32" LCD telly coupled to a Sky HD box. Most broadcast output is of excellent picture quality whether HD or standard definition. However on some of the channels, eg. those which specialise in 70s and 80s American series the picture can be blocky and grainy. Is this down to the quality of the original recording or do I need to make adjustments?

[thundercrack]

sky send the signal to your dish at different strengths, so if you are talking about the more unheard of channels they will be weaker than the film channels and bbc etc. It depends on how much a broadcaster is prepared to pay sky to transmit its station.
most unlikely that there is anything wrong with your equipment.

[ACtheTROLL]

Basically you can't make a silk purse out of .....
think about our telly .... **************'s Half Hour or Steptoe and Son were transmitted in 405 lines
Then 625 lines took over .... but was recorded on tape
now digital recording is standard ... and quality is excellent accross the board.

The USA uses a different system called NTSC which used to be recorded using less detail ...
(because even in the old days they had many more channels than we ever did. The bandwidth available was less ... and so the detail is less).

america still isn't known for it's broadcast quality - but because digital recording is pretty universal these days ... the export quality is (almost) as good as ours.





LOL don't know which planet thundercrack is from by his explanation you should be able to cook using the signal from the BBC!!!

[pug100]

Hi,
The blockiness that you are seeing is called pixellation and is a product of the DIGITAL transmission system and is not due to the original soucre material. The graininess however IS probably due the lower quality of the original recordings.

When broadcasters buy space on Sky's satellite they have to pay according to how much bandwidth they require. This bandwidth is measured in Mega Bits per second and the easiest way to imagine this is with water flowing through a pipe. If you have a big diameter pipe you can put lots of water down it, but if you only have a small pipe only a small amount of water can flow.

A channel such as BBC1 will pay loads and use around 10mbps whereas a smaller broadcaster would pay for say 6mbps. When you go to the HD channels then the numbers get bigger these will use 20 to 50 mbps as they need to contain a lot more data.